xref: /linux/net/sunrpc/xdr.c (revision 2eb2b935)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * linux/net/sunrpc/xdr.c
4  *
5  * Generic XDR support.
6  *
7  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8  */
9 
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/types.h>
13 #include <linux/string.h>
14 #include <linux/kernel.h>
15 #include <linux/pagemap.h>
16 #include <linux/errno.h>
17 #include <linux/sunrpc/xdr.h>
18 #include <linux/sunrpc/msg_prot.h>
19 #include <linux/bvec.h>
20 #include <trace/events/sunrpc.h>
21 
22 static void _copy_to_pages(struct page **, size_t, const char *, size_t);
23 
24 
25 /*
26  * XDR functions for basic NFS types
27  */
28 __be32 *
xdr_encode_netobj(__be32 * p,const struct xdr_netobj * obj)29 xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
30 {
31 	unsigned int	quadlen = XDR_QUADLEN(obj->len);
32 
33 	p[quadlen] = 0;		/* zero trailing bytes */
34 	*p++ = cpu_to_be32(obj->len);
35 	memcpy(p, obj->data, obj->len);
36 	return p + XDR_QUADLEN(obj->len);
37 }
38 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
39 
40 __be32 *
xdr_decode_netobj(__be32 * p,struct xdr_netobj * obj)41 xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
42 {
43 	unsigned int	len;
44 
45 	if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
46 		return NULL;
47 	obj->len  = len;
48 	obj->data = (u8 *) p;
49 	return p + XDR_QUADLEN(len);
50 }
51 EXPORT_SYMBOL_GPL(xdr_decode_netobj);
52 
53 /**
54  * xdr_encode_opaque_fixed - Encode fixed length opaque data
55  * @p: pointer to current position in XDR buffer.
56  * @ptr: pointer to data to encode (or NULL)
57  * @nbytes: size of data.
58  *
59  * Copy the array of data of length nbytes at ptr to the XDR buffer
60  * at position p, then align to the next 32-bit boundary by padding
61  * with zero bytes (see RFC1832).
62  * Note: if ptr is NULL, only the padding is performed.
63  *
64  * Returns the updated current XDR buffer position
65  *
66  */
xdr_encode_opaque_fixed(__be32 * p,const void * ptr,unsigned int nbytes)67 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
68 {
69 	if (likely(nbytes != 0)) {
70 		unsigned int quadlen = XDR_QUADLEN(nbytes);
71 		unsigned int padding = (quadlen << 2) - nbytes;
72 
73 		if (ptr != NULL)
74 			memcpy(p, ptr, nbytes);
75 		if (padding != 0)
76 			memset((char *)p + nbytes, 0, padding);
77 		p += quadlen;
78 	}
79 	return p;
80 }
81 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
82 
83 /**
84  * xdr_encode_opaque - Encode variable length opaque data
85  * @p: pointer to current position in XDR buffer.
86  * @ptr: pointer to data to encode (or NULL)
87  * @nbytes: size of data.
88  *
89  * Returns the updated current XDR buffer position
90  */
xdr_encode_opaque(__be32 * p,const void * ptr,unsigned int nbytes)91 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
92 {
93 	*p++ = cpu_to_be32(nbytes);
94 	return xdr_encode_opaque_fixed(p, ptr, nbytes);
95 }
96 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
97 
98 __be32 *
xdr_encode_string(__be32 * p,const char * string)99 xdr_encode_string(__be32 *p, const char *string)
100 {
101 	return xdr_encode_array(p, string, strlen(string));
102 }
103 EXPORT_SYMBOL_GPL(xdr_encode_string);
104 
105 __be32 *
xdr_decode_string_inplace(__be32 * p,char ** sp,unsigned int * lenp,unsigned int maxlen)106 xdr_decode_string_inplace(__be32 *p, char **sp,
107 			  unsigned int *lenp, unsigned int maxlen)
108 {
109 	u32 len;
110 
111 	len = be32_to_cpu(*p++);
112 	if (len > maxlen)
113 		return NULL;
114 	*lenp = len;
115 	*sp = (char *) p;
116 	return p + XDR_QUADLEN(len);
117 }
118 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
119 
120 /**
121  * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
122  * @buf: XDR buffer where string resides
123  * @len: length of string, in bytes
124  *
125  */
xdr_terminate_string(const struct xdr_buf * buf,const u32 len)126 void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
127 {
128 	char *kaddr;
129 
130 	kaddr = kmap_atomic(buf->pages[0]);
131 	kaddr[buf->page_base + len] = '\0';
132 	kunmap_atomic(kaddr);
133 }
134 EXPORT_SYMBOL_GPL(xdr_terminate_string);
135 
xdr_buf_pagecount(const struct xdr_buf * buf)136 size_t xdr_buf_pagecount(const struct xdr_buf *buf)
137 {
138 	if (!buf->page_len)
139 		return 0;
140 	return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
141 }
142 
143 int
xdr_alloc_bvec(struct xdr_buf * buf,gfp_t gfp)144 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
145 {
146 	size_t i, n = xdr_buf_pagecount(buf);
147 
148 	if (n != 0 && buf->bvec == NULL) {
149 		buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
150 		if (!buf->bvec)
151 			return -ENOMEM;
152 		for (i = 0; i < n; i++) {
153 			bvec_set_page(&buf->bvec[i], buf->pages[i], PAGE_SIZE,
154 				      0);
155 		}
156 	}
157 	return 0;
158 }
159 
160 void
xdr_free_bvec(struct xdr_buf * buf)161 xdr_free_bvec(struct xdr_buf *buf)
162 {
163 	kfree(buf->bvec);
164 	buf->bvec = NULL;
165 }
166 
167 /**
168  * xdr_buf_to_bvec - Copy components of an xdr_buf into a bio_vec array
169  * @bvec: bio_vec array to populate
170  * @bvec_size: element count of @bio_vec
171  * @xdr: xdr_buf to be copied
172  *
173  * Returns the number of entries consumed in @bvec.
174  */
xdr_buf_to_bvec(struct bio_vec * bvec,unsigned int bvec_size,const struct xdr_buf * xdr)175 unsigned int xdr_buf_to_bvec(struct bio_vec *bvec, unsigned int bvec_size,
176 			     const struct xdr_buf *xdr)
177 {
178 	const struct kvec *head = xdr->head;
179 	const struct kvec *tail = xdr->tail;
180 	unsigned int count = 0;
181 
182 	if (head->iov_len) {
183 		bvec_set_virt(bvec++, head->iov_base, head->iov_len);
184 		++count;
185 	}
186 
187 	if (xdr->page_len) {
188 		unsigned int offset, len, remaining;
189 		struct page **pages = xdr->pages;
190 
191 		offset = offset_in_page(xdr->page_base);
192 		remaining = xdr->page_len;
193 		while (remaining > 0) {
194 			len = min_t(unsigned int, remaining,
195 				    PAGE_SIZE - offset);
196 			bvec_set_page(bvec++, *pages++, len, offset);
197 			remaining -= len;
198 			offset = 0;
199 			if (unlikely(++count > bvec_size))
200 				goto bvec_overflow;
201 		}
202 	}
203 
204 	if (tail->iov_len) {
205 		bvec_set_virt(bvec, tail->iov_base, tail->iov_len);
206 		if (unlikely(++count > bvec_size))
207 			goto bvec_overflow;
208 	}
209 
210 	return count;
211 
212 bvec_overflow:
213 	pr_warn_once("%s: bio_vec array overflow\n", __func__);
214 	return count - 1;
215 }
216 
217 /**
218  * xdr_inline_pages - Prepare receive buffer for a large reply
219  * @xdr: xdr_buf into which reply will be placed
220  * @offset: expected offset where data payload will start, in bytes
221  * @pages: vector of struct page pointers
222  * @base: offset in first page where receive should start, in bytes
223  * @len: expected size of the upper layer data payload, in bytes
224  *
225  */
226 void
xdr_inline_pages(struct xdr_buf * xdr,unsigned int offset,struct page ** pages,unsigned int base,unsigned int len)227 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
228 		 struct page **pages, unsigned int base, unsigned int len)
229 {
230 	struct kvec *head = xdr->head;
231 	struct kvec *tail = xdr->tail;
232 	char *buf = (char *)head->iov_base;
233 	unsigned int buflen = head->iov_len;
234 
235 	head->iov_len  = offset;
236 
237 	xdr->pages = pages;
238 	xdr->page_base = base;
239 	xdr->page_len = len;
240 
241 	tail->iov_base = buf + offset;
242 	tail->iov_len = buflen - offset;
243 	xdr->buflen += len;
244 }
245 EXPORT_SYMBOL_GPL(xdr_inline_pages);
246 
247 /*
248  * Helper routines for doing 'memmove' like operations on a struct xdr_buf
249  */
250 
251 /**
252  * _shift_data_left_pages
253  * @pages: vector of pages containing both the source and dest memory area.
254  * @pgto_base: page vector address of destination
255  * @pgfrom_base: page vector address of source
256  * @len: number of bytes to copy
257  *
258  * Note: the addresses pgto_base and pgfrom_base are both calculated in
259  *       the same way:
260  *            if a memory area starts at byte 'base' in page 'pages[i]',
261  *            then its address is given as (i << PAGE_CACHE_SHIFT) + base
262  * Alse note: pgto_base must be < pgfrom_base, but the memory areas
263  * 	they point to may overlap.
264  */
265 static void
_shift_data_left_pages(struct page ** pages,size_t pgto_base,size_t pgfrom_base,size_t len)266 _shift_data_left_pages(struct page **pages, size_t pgto_base,
267 			size_t pgfrom_base, size_t len)
268 {
269 	struct page **pgfrom, **pgto;
270 	char *vfrom, *vto;
271 	size_t copy;
272 
273 	BUG_ON(pgfrom_base <= pgto_base);
274 
275 	if (!len)
276 		return;
277 
278 	pgto = pages + (pgto_base >> PAGE_SHIFT);
279 	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
280 
281 	pgto_base &= ~PAGE_MASK;
282 	pgfrom_base &= ~PAGE_MASK;
283 
284 	do {
285 		if (pgto_base >= PAGE_SIZE) {
286 			pgto_base = 0;
287 			pgto++;
288 		}
289 		if (pgfrom_base >= PAGE_SIZE){
290 			pgfrom_base = 0;
291 			pgfrom++;
292 		}
293 
294 		copy = len;
295 		if (copy > (PAGE_SIZE - pgto_base))
296 			copy = PAGE_SIZE - pgto_base;
297 		if (copy > (PAGE_SIZE - pgfrom_base))
298 			copy = PAGE_SIZE - pgfrom_base;
299 
300 		vto = kmap_atomic(*pgto);
301 		if (*pgto != *pgfrom) {
302 			vfrom = kmap_atomic(*pgfrom);
303 			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
304 			kunmap_atomic(vfrom);
305 		} else
306 			memmove(vto + pgto_base, vto + pgfrom_base, copy);
307 		flush_dcache_page(*pgto);
308 		kunmap_atomic(vto);
309 
310 		pgto_base += copy;
311 		pgfrom_base += copy;
312 
313 	} while ((len -= copy) != 0);
314 }
315 
316 /**
317  * _shift_data_right_pages
318  * @pages: vector of pages containing both the source and dest memory area.
319  * @pgto_base: page vector address of destination
320  * @pgfrom_base: page vector address of source
321  * @len: number of bytes to copy
322  *
323  * Note: the addresses pgto_base and pgfrom_base are both calculated in
324  *       the same way:
325  *            if a memory area starts at byte 'base' in page 'pages[i]',
326  *            then its address is given as (i << PAGE_SHIFT) + base
327  * Also note: pgfrom_base must be < pgto_base, but the memory areas
328  * 	they point to may overlap.
329  */
330 static void
_shift_data_right_pages(struct page ** pages,size_t pgto_base,size_t pgfrom_base,size_t len)331 _shift_data_right_pages(struct page **pages, size_t pgto_base,
332 		size_t pgfrom_base, size_t len)
333 {
334 	struct page **pgfrom, **pgto;
335 	char *vfrom, *vto;
336 	size_t copy;
337 
338 	BUG_ON(pgto_base <= pgfrom_base);
339 
340 	if (!len)
341 		return;
342 
343 	pgto_base += len;
344 	pgfrom_base += len;
345 
346 	pgto = pages + (pgto_base >> PAGE_SHIFT);
347 	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
348 
349 	pgto_base &= ~PAGE_MASK;
350 	pgfrom_base &= ~PAGE_MASK;
351 
352 	do {
353 		/* Are any pointers crossing a page boundary? */
354 		if (pgto_base == 0) {
355 			pgto_base = PAGE_SIZE;
356 			pgto--;
357 		}
358 		if (pgfrom_base == 0) {
359 			pgfrom_base = PAGE_SIZE;
360 			pgfrom--;
361 		}
362 
363 		copy = len;
364 		if (copy > pgto_base)
365 			copy = pgto_base;
366 		if (copy > pgfrom_base)
367 			copy = pgfrom_base;
368 		pgto_base -= copy;
369 		pgfrom_base -= copy;
370 
371 		vto = kmap_atomic(*pgto);
372 		if (*pgto != *pgfrom) {
373 			vfrom = kmap_atomic(*pgfrom);
374 			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
375 			kunmap_atomic(vfrom);
376 		} else
377 			memmove(vto + pgto_base, vto + pgfrom_base, copy);
378 		flush_dcache_page(*pgto);
379 		kunmap_atomic(vto);
380 
381 	} while ((len -= copy) != 0);
382 }
383 
384 /**
385  * _copy_to_pages
386  * @pages: array of pages
387  * @pgbase: page vector address of destination
388  * @p: pointer to source data
389  * @len: length
390  *
391  * Copies data from an arbitrary memory location into an array of pages
392  * The copy is assumed to be non-overlapping.
393  */
394 static void
_copy_to_pages(struct page ** pages,size_t pgbase,const char * p,size_t len)395 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
396 {
397 	struct page **pgto;
398 	char *vto;
399 	size_t copy;
400 
401 	if (!len)
402 		return;
403 
404 	pgto = pages + (pgbase >> PAGE_SHIFT);
405 	pgbase &= ~PAGE_MASK;
406 
407 	for (;;) {
408 		copy = PAGE_SIZE - pgbase;
409 		if (copy > len)
410 			copy = len;
411 
412 		vto = kmap_atomic(*pgto);
413 		memcpy(vto + pgbase, p, copy);
414 		kunmap_atomic(vto);
415 
416 		len -= copy;
417 		if (len == 0)
418 			break;
419 
420 		pgbase += copy;
421 		if (pgbase == PAGE_SIZE) {
422 			flush_dcache_page(*pgto);
423 			pgbase = 0;
424 			pgto++;
425 		}
426 		p += copy;
427 	}
428 	flush_dcache_page(*pgto);
429 }
430 
431 /**
432  * _copy_from_pages
433  * @p: pointer to destination
434  * @pages: array of pages
435  * @pgbase: offset of source data
436  * @len: length
437  *
438  * Copies data into an arbitrary memory location from an array of pages
439  * The copy is assumed to be non-overlapping.
440  */
441 void
_copy_from_pages(char * p,struct page ** pages,size_t pgbase,size_t len)442 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
443 {
444 	struct page **pgfrom;
445 	char *vfrom;
446 	size_t copy;
447 
448 	if (!len)
449 		return;
450 
451 	pgfrom = pages + (pgbase >> PAGE_SHIFT);
452 	pgbase &= ~PAGE_MASK;
453 
454 	do {
455 		copy = PAGE_SIZE - pgbase;
456 		if (copy > len)
457 			copy = len;
458 
459 		vfrom = kmap_atomic(*pgfrom);
460 		memcpy(p, vfrom + pgbase, copy);
461 		kunmap_atomic(vfrom);
462 
463 		pgbase += copy;
464 		if (pgbase == PAGE_SIZE) {
465 			pgbase = 0;
466 			pgfrom++;
467 		}
468 		p += copy;
469 
470 	} while ((len -= copy) != 0);
471 }
472 EXPORT_SYMBOL_GPL(_copy_from_pages);
473 
xdr_buf_iov_zero(const struct kvec * iov,unsigned int base,unsigned int len)474 static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
475 			     unsigned int len)
476 {
477 	if (base >= iov->iov_len)
478 		return;
479 	if (len > iov->iov_len - base)
480 		len = iov->iov_len - base;
481 	memset(iov->iov_base + base, 0, len);
482 }
483 
484 /**
485  * xdr_buf_pages_zero
486  * @buf: xdr_buf
487  * @pgbase: beginning offset
488  * @len: length
489  */
xdr_buf_pages_zero(const struct xdr_buf * buf,unsigned int pgbase,unsigned int len)490 static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
491 			       unsigned int len)
492 {
493 	struct page **pages = buf->pages;
494 	struct page **page;
495 	char *vpage;
496 	unsigned int zero;
497 
498 	if (!len)
499 		return;
500 	if (pgbase >= buf->page_len) {
501 		xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
502 		return;
503 	}
504 	if (pgbase + len > buf->page_len) {
505 		xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
506 		len = buf->page_len - pgbase;
507 	}
508 
509 	pgbase += buf->page_base;
510 
511 	page = pages + (pgbase >> PAGE_SHIFT);
512 	pgbase &= ~PAGE_MASK;
513 
514 	do {
515 		zero = PAGE_SIZE - pgbase;
516 		if (zero > len)
517 			zero = len;
518 
519 		vpage = kmap_atomic(*page);
520 		memset(vpage + pgbase, 0, zero);
521 		kunmap_atomic(vpage);
522 
523 		flush_dcache_page(*page);
524 		pgbase = 0;
525 		page++;
526 
527 	} while ((len -= zero) != 0);
528 }
529 
xdr_buf_pages_fill_sparse(const struct xdr_buf * buf,unsigned int buflen,gfp_t gfp)530 static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
531 					      unsigned int buflen, gfp_t gfp)
532 {
533 	unsigned int i, npages, pagelen;
534 
535 	if (!(buf->flags & XDRBUF_SPARSE_PAGES))
536 		return buflen;
537 	if (buflen <= buf->head->iov_len)
538 		return buflen;
539 	pagelen = buflen - buf->head->iov_len;
540 	if (pagelen > buf->page_len)
541 		pagelen = buf->page_len;
542 	npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
543 	for (i = 0; i < npages; i++) {
544 		if (!buf->pages[i])
545 			continue;
546 		buf->pages[i] = alloc_page(gfp);
547 		if (likely(buf->pages[i]))
548 			continue;
549 		buflen -= pagelen;
550 		pagelen = i << PAGE_SHIFT;
551 		if (pagelen > buf->page_base)
552 			buflen += pagelen - buf->page_base;
553 		break;
554 	}
555 	return buflen;
556 }
557 
xdr_buf_try_expand(struct xdr_buf * buf,unsigned int len)558 static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
559 {
560 	struct kvec *head = buf->head;
561 	struct kvec *tail = buf->tail;
562 	unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
563 	unsigned int free_space, newlen;
564 
565 	if (sum > buf->len) {
566 		free_space = min_t(unsigned int, sum - buf->len, len);
567 		newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
568 						   GFP_KERNEL);
569 		free_space = newlen - buf->len;
570 		buf->len = newlen;
571 		len -= free_space;
572 		if (!len)
573 			return;
574 	}
575 
576 	if (buf->buflen > sum) {
577 		/* Expand the tail buffer */
578 		free_space = min_t(unsigned int, buf->buflen - sum, len);
579 		tail->iov_len += free_space;
580 		buf->len += free_space;
581 	}
582 }
583 
xdr_buf_tail_copy_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)584 static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
585 				    unsigned int base, unsigned int len,
586 				    unsigned int shift)
587 {
588 	const struct kvec *tail = buf->tail;
589 	unsigned int to = base + shift;
590 
591 	if (to >= tail->iov_len)
592 		return;
593 	if (len + to > tail->iov_len)
594 		len = tail->iov_len - to;
595 	memmove(tail->iov_base + to, tail->iov_base + base, len);
596 }
597 
xdr_buf_pages_copy_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)598 static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
599 				     unsigned int base, unsigned int len,
600 				     unsigned int shift)
601 {
602 	const struct kvec *tail = buf->tail;
603 	unsigned int to = base + shift;
604 	unsigned int pglen = 0;
605 	unsigned int talen = 0, tato = 0;
606 
607 	if (base >= buf->page_len)
608 		return;
609 	if (len > buf->page_len - base)
610 		len = buf->page_len - base;
611 	if (to >= buf->page_len) {
612 		tato = to - buf->page_len;
613 		if (tail->iov_len >= len + tato)
614 			talen = len;
615 		else if (tail->iov_len > tato)
616 			talen = tail->iov_len - tato;
617 	} else if (len + to >= buf->page_len) {
618 		pglen = buf->page_len - to;
619 		talen = len - pglen;
620 		if (talen > tail->iov_len)
621 			talen = tail->iov_len;
622 	} else
623 		pglen = len;
624 
625 	_copy_from_pages(tail->iov_base + tato, buf->pages,
626 			 buf->page_base + base + pglen, talen);
627 	_shift_data_right_pages(buf->pages, buf->page_base + to,
628 				buf->page_base + base, pglen);
629 }
630 
xdr_buf_head_copy_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)631 static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
632 				    unsigned int base, unsigned int len,
633 				    unsigned int shift)
634 {
635 	const struct kvec *head = buf->head;
636 	const struct kvec *tail = buf->tail;
637 	unsigned int to = base + shift;
638 	unsigned int pglen = 0, pgto = 0;
639 	unsigned int talen = 0, tato = 0;
640 
641 	if (base >= head->iov_len)
642 		return;
643 	if (len > head->iov_len - base)
644 		len = head->iov_len - base;
645 	if (to >= buf->page_len + head->iov_len) {
646 		tato = to - buf->page_len - head->iov_len;
647 		talen = len;
648 	} else if (to >= head->iov_len) {
649 		pgto = to - head->iov_len;
650 		pglen = len;
651 		if (pgto + pglen > buf->page_len) {
652 			talen = pgto + pglen - buf->page_len;
653 			pglen -= talen;
654 		}
655 	} else {
656 		pglen = len - to;
657 		if (pglen > buf->page_len) {
658 			talen = pglen - buf->page_len;
659 			pglen = buf->page_len;
660 		}
661 	}
662 
663 	len -= talen;
664 	base += len;
665 	if (talen + tato > tail->iov_len)
666 		talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
667 	memcpy(tail->iov_base + tato, head->iov_base + base, talen);
668 
669 	len -= pglen;
670 	base -= pglen;
671 	_copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
672 		       pglen);
673 
674 	base -= len;
675 	memmove(head->iov_base + to, head->iov_base + base, len);
676 }
677 
xdr_buf_tail_shift_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)678 static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
679 				     unsigned int base, unsigned int len,
680 				     unsigned int shift)
681 {
682 	const struct kvec *tail = buf->tail;
683 
684 	if (base >= tail->iov_len || !shift || !len)
685 		return;
686 	xdr_buf_tail_copy_right(buf, base, len, shift);
687 }
688 
xdr_buf_pages_shift_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)689 static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
690 				      unsigned int base, unsigned int len,
691 				      unsigned int shift)
692 {
693 	if (!shift || !len)
694 		return;
695 	if (base >= buf->page_len) {
696 		xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
697 		return;
698 	}
699 	if (base + len > buf->page_len)
700 		xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
701 					 shift);
702 	xdr_buf_pages_copy_right(buf, base, len, shift);
703 }
704 
xdr_buf_head_shift_right(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)705 static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
706 				     unsigned int base, unsigned int len,
707 				     unsigned int shift)
708 {
709 	const struct kvec *head = buf->head;
710 
711 	if (!shift)
712 		return;
713 	if (base >= head->iov_len) {
714 		xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
715 					  shift);
716 		return;
717 	}
718 	if (base + len > head->iov_len)
719 		xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
720 					  shift);
721 	xdr_buf_head_copy_right(buf, base, len, shift);
722 }
723 
xdr_buf_tail_copy_left(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)724 static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
725 				   unsigned int len, unsigned int shift)
726 {
727 	const struct kvec *tail = buf->tail;
728 
729 	if (base >= tail->iov_len)
730 		return;
731 	if (len > tail->iov_len - base)
732 		len = tail->iov_len - base;
733 	/* Shift data into head */
734 	if (shift > buf->page_len + base) {
735 		const struct kvec *head = buf->head;
736 		unsigned int hdto =
737 			head->iov_len + buf->page_len + base - shift;
738 		unsigned int hdlen = len;
739 
740 		if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
741 			      "SUNRPC: Misaligned data.\n"))
742 			return;
743 		if (hdto + hdlen > head->iov_len)
744 			hdlen = head->iov_len - hdto;
745 		memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
746 		base += hdlen;
747 		len -= hdlen;
748 		if (!len)
749 			return;
750 	}
751 	/* Shift data into pages */
752 	if (shift > base) {
753 		unsigned int pgto = buf->page_len + base - shift;
754 		unsigned int pglen = len;
755 
756 		if (pgto + pglen > buf->page_len)
757 			pglen = buf->page_len - pgto;
758 		_copy_to_pages(buf->pages, buf->page_base + pgto,
759 			       tail->iov_base + base, pglen);
760 		base += pglen;
761 		len -= pglen;
762 		if (!len)
763 			return;
764 	}
765 	memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
766 }
767 
xdr_buf_pages_copy_left(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)768 static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
769 				    unsigned int base, unsigned int len,
770 				    unsigned int shift)
771 {
772 	unsigned int pgto;
773 
774 	if (base >= buf->page_len)
775 		return;
776 	if (len > buf->page_len - base)
777 		len = buf->page_len - base;
778 	/* Shift data into head */
779 	if (shift > base) {
780 		const struct kvec *head = buf->head;
781 		unsigned int hdto = head->iov_len + base - shift;
782 		unsigned int hdlen = len;
783 
784 		if (WARN_ONCE(shift > head->iov_len + base,
785 			      "SUNRPC: Misaligned data.\n"))
786 			return;
787 		if (hdto + hdlen > head->iov_len)
788 			hdlen = head->iov_len - hdto;
789 		_copy_from_pages(head->iov_base + hdto, buf->pages,
790 				 buf->page_base + base, hdlen);
791 		base += hdlen;
792 		len -= hdlen;
793 		if (!len)
794 			return;
795 	}
796 	pgto = base - shift;
797 	_shift_data_left_pages(buf->pages, buf->page_base + pgto,
798 			       buf->page_base + base, len);
799 }
800 
xdr_buf_tail_shift_left(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)801 static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
802 				    unsigned int base, unsigned int len,
803 				    unsigned int shift)
804 {
805 	if (!shift || !len)
806 		return;
807 	xdr_buf_tail_copy_left(buf, base, len, shift);
808 }
809 
xdr_buf_pages_shift_left(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)810 static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
811 				     unsigned int base, unsigned int len,
812 				     unsigned int shift)
813 {
814 	if (!shift || !len)
815 		return;
816 	if (base >= buf->page_len) {
817 		xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
818 		return;
819 	}
820 	xdr_buf_pages_copy_left(buf, base, len, shift);
821 	len += base;
822 	if (len <= buf->page_len)
823 		return;
824 	xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
825 }
826 
xdr_buf_head_shift_left(const struct xdr_buf * buf,unsigned int base,unsigned int len,unsigned int shift)827 static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
828 				    unsigned int base, unsigned int len,
829 				    unsigned int shift)
830 {
831 	const struct kvec *head = buf->head;
832 	unsigned int bytes;
833 
834 	if (!shift || !len)
835 		return;
836 
837 	if (shift > base) {
838 		bytes = (shift - base);
839 		if (bytes >= len)
840 			return;
841 		base += bytes;
842 		len -= bytes;
843 	}
844 
845 	if (base < head->iov_len) {
846 		bytes = min_t(unsigned int, len, head->iov_len - base);
847 		memmove(head->iov_base + (base - shift),
848 			head->iov_base + base, bytes);
849 		base += bytes;
850 		len -= bytes;
851 	}
852 	xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
853 }
854 
855 /**
856  * xdr_shrink_bufhead
857  * @buf: xdr_buf
858  * @len: new length of buf->head[0]
859  *
860  * Shrinks XDR buffer's header kvec buf->head[0], setting it to
861  * 'len' bytes. The extra data is not lost, but is instead
862  * moved into the inlined pages and/or the tail.
863  */
xdr_shrink_bufhead(struct xdr_buf * buf,unsigned int len)864 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
865 {
866 	struct kvec *head = buf->head;
867 	unsigned int shift, buflen = max(buf->len, len);
868 
869 	WARN_ON_ONCE(len > head->iov_len);
870 	if (head->iov_len > buflen) {
871 		buf->buflen -= head->iov_len - buflen;
872 		head->iov_len = buflen;
873 	}
874 	if (len >= head->iov_len)
875 		return 0;
876 	shift = head->iov_len - len;
877 	xdr_buf_try_expand(buf, shift);
878 	xdr_buf_head_shift_right(buf, len, buflen - len, shift);
879 	head->iov_len = len;
880 	buf->buflen -= shift;
881 	buf->len -= shift;
882 	return shift;
883 }
884 
885 /**
886  * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
887  * @buf: xdr_buf
888  * @len: new page buffer length
889  *
890  * The extra data is not lost, but is instead moved into buf->tail.
891  * Returns the actual number of bytes moved.
892  */
xdr_shrink_pagelen(struct xdr_buf * buf,unsigned int len)893 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
894 {
895 	unsigned int shift, buflen = buf->len - buf->head->iov_len;
896 
897 	WARN_ON_ONCE(len > buf->page_len);
898 	if (buf->head->iov_len >= buf->len || len > buflen)
899 		buflen = len;
900 	if (buf->page_len > buflen) {
901 		buf->buflen -= buf->page_len - buflen;
902 		buf->page_len = buflen;
903 	}
904 	if (len >= buf->page_len)
905 		return 0;
906 	shift = buf->page_len - len;
907 	xdr_buf_try_expand(buf, shift);
908 	xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
909 	buf->page_len = len;
910 	buf->len -= shift;
911 	buf->buflen -= shift;
912 	return shift;
913 }
914 
915 /**
916  * xdr_stream_pos - Return the current offset from the start of the xdr_stream
917  * @xdr: pointer to struct xdr_stream
918  */
xdr_stream_pos(const struct xdr_stream * xdr)919 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
920 {
921 	return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
922 }
923 EXPORT_SYMBOL_GPL(xdr_stream_pos);
924 
xdr_stream_set_pos(struct xdr_stream * xdr,unsigned int pos)925 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
926 {
927 	unsigned int blen = xdr->buf->len;
928 
929 	xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
930 }
931 
xdr_stream_page_set_pos(struct xdr_stream * xdr,unsigned int pos)932 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
933 {
934 	xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
935 }
936 
937 /**
938  * xdr_page_pos - Return the current offset from the start of the xdr pages
939  * @xdr: pointer to struct xdr_stream
940  */
xdr_page_pos(const struct xdr_stream * xdr)941 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
942 {
943 	unsigned int pos = xdr_stream_pos(xdr);
944 
945 	WARN_ON(pos < xdr->buf->head[0].iov_len);
946 	return pos - xdr->buf->head[0].iov_len;
947 }
948 EXPORT_SYMBOL_GPL(xdr_page_pos);
949 
950 /**
951  * xdr_init_encode - Initialize a struct xdr_stream for sending data.
952  * @xdr: pointer to xdr_stream struct
953  * @buf: pointer to XDR buffer in which to encode data
954  * @p: current pointer inside XDR buffer
955  * @rqst: pointer to controlling rpc_rqst, for debugging
956  *
957  * Note: at the moment the RPC client only passes the length of our
958  *	 scratch buffer in the xdr_buf's header kvec. Previously this
959  *	 meant we needed to call xdr_adjust_iovec() after encoding the
960  *	 data. With the new scheme, the xdr_stream manages the details
961  *	 of the buffer length, and takes care of adjusting the kvec
962  *	 length for us.
963  */
xdr_init_encode(struct xdr_stream * xdr,struct xdr_buf * buf,__be32 * p,struct rpc_rqst * rqst)964 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
965 		     struct rpc_rqst *rqst)
966 {
967 	struct kvec *iov = buf->head;
968 	int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
969 
970 	xdr_reset_scratch_buffer(xdr);
971 	BUG_ON(scratch_len < 0);
972 	xdr->buf = buf;
973 	xdr->iov = iov;
974 	xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
975 	xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
976 	BUG_ON(iov->iov_len > scratch_len);
977 
978 	if (p != xdr->p && p != NULL) {
979 		size_t len;
980 
981 		BUG_ON(p < xdr->p || p > xdr->end);
982 		len = (char *)p - (char *)xdr->p;
983 		xdr->p = p;
984 		buf->len += len;
985 		iov->iov_len += len;
986 	}
987 	xdr->rqst = rqst;
988 }
989 EXPORT_SYMBOL_GPL(xdr_init_encode);
990 
991 /**
992  * xdr_init_encode_pages - Initialize an xdr_stream for encoding into pages
993  * @xdr: pointer to xdr_stream struct
994  * @buf: pointer to XDR buffer into which to encode data
995  * @pages: list of pages to decode into
996  * @rqst: pointer to controlling rpc_rqst, for debugging
997  *
998  */
xdr_init_encode_pages(struct xdr_stream * xdr,struct xdr_buf * buf,struct page ** pages,struct rpc_rqst * rqst)999 void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1000 			   struct page **pages, struct rpc_rqst *rqst)
1001 {
1002 	xdr_reset_scratch_buffer(xdr);
1003 
1004 	xdr->buf = buf;
1005 	xdr->page_ptr = pages;
1006 	xdr->iov = NULL;
1007 	xdr->p = page_address(*pages);
1008 	xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE);
1009 	xdr->rqst = rqst;
1010 }
1011 EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
1012 
1013 /**
1014  * __xdr_commit_encode - Ensure all data is written to buffer
1015  * @xdr: pointer to xdr_stream
1016  *
1017  * We handle encoding across page boundaries by giving the caller a
1018  * temporary location to write to, then later copying the data into
1019  * place; xdr_commit_encode does that copying.
1020  *
1021  * Normally the caller doesn't need to call this directly, as the
1022  * following xdr_reserve_space will do it.  But an explicit call may be
1023  * required at the end of encoding, or any other time when the xdr_buf
1024  * data might be read.
1025  */
__xdr_commit_encode(struct xdr_stream * xdr)1026 void __xdr_commit_encode(struct xdr_stream *xdr)
1027 {
1028 	size_t shift = xdr->scratch.iov_len;
1029 	void *page;
1030 
1031 	page = page_address(*xdr->page_ptr);
1032 	memcpy(xdr->scratch.iov_base, page, shift);
1033 	memmove(page, page + shift, (void *)xdr->p - page);
1034 	xdr_reset_scratch_buffer(xdr);
1035 }
1036 EXPORT_SYMBOL_GPL(__xdr_commit_encode);
1037 
1038 /*
1039  * The buffer space to be reserved crosses the boundary between
1040  * xdr->buf->head and xdr->buf->pages, or between two pages
1041  * in xdr->buf->pages.
1042  */
xdr_get_next_encode_buffer(struct xdr_stream * xdr,size_t nbytes)1043 static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
1044 						   size_t nbytes)
1045 {
1046 	int space_left;
1047 	int frag1bytes, frag2bytes;
1048 	void *p;
1049 
1050 	if (nbytes > PAGE_SIZE)
1051 		goto out_overflow; /* Bigger buffers require special handling */
1052 	if (xdr->buf->len + nbytes > xdr->buf->buflen)
1053 		goto out_overflow; /* Sorry, we're totally out of space */
1054 	frag1bytes = (xdr->end - xdr->p) << 2;
1055 	frag2bytes = nbytes - frag1bytes;
1056 	if (xdr->iov)
1057 		xdr->iov->iov_len += frag1bytes;
1058 	else
1059 		xdr->buf->page_len += frag1bytes;
1060 	xdr->page_ptr++;
1061 	xdr->iov = NULL;
1062 
1063 	/*
1064 	 * If the last encode didn't end exactly on a page boundary, the
1065 	 * next one will straddle boundaries.  Encode into the next
1066 	 * page, then copy it back later in xdr_commit_encode.  We use
1067 	 * the "scratch" iov to track any temporarily unused fragment of
1068 	 * space at the end of the previous buffer:
1069 	 */
1070 	xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
1071 
1072 	/*
1073 	 * xdr->p is where the next encode will start after
1074 	 * xdr_commit_encode() has shifted this one back:
1075 	 */
1076 	p = page_address(*xdr->page_ptr);
1077 	xdr->p = p + frag2bytes;
1078 	space_left = xdr->buf->buflen - xdr->buf->len;
1079 	if (space_left - frag1bytes >= PAGE_SIZE)
1080 		xdr->end = p + PAGE_SIZE;
1081 	else
1082 		xdr->end = p + space_left - frag1bytes;
1083 
1084 	xdr->buf->page_len += frag2bytes;
1085 	xdr->buf->len += nbytes;
1086 	return p;
1087 out_overflow:
1088 	trace_rpc_xdr_overflow(xdr, nbytes);
1089 	return NULL;
1090 }
1091 
1092 /**
1093  * xdr_reserve_space - Reserve buffer space for sending
1094  * @xdr: pointer to xdr_stream
1095  * @nbytes: number of bytes to reserve
1096  *
1097  * Checks that we have enough buffer space to encode 'nbytes' more
1098  * bytes of data. If so, update the total xdr_buf length, and
1099  * adjust the length of the current kvec.
1100  */
xdr_reserve_space(struct xdr_stream * xdr,size_t nbytes)1101 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1102 {
1103 	__be32 *p = xdr->p;
1104 	__be32 *q;
1105 
1106 	xdr_commit_encode(xdr);
1107 	/* align nbytes on the next 32-bit boundary */
1108 	nbytes += 3;
1109 	nbytes &= ~3;
1110 	q = p + (nbytes >> 2);
1111 	if (unlikely(q > xdr->end || q < p))
1112 		return xdr_get_next_encode_buffer(xdr, nbytes);
1113 	xdr->p = q;
1114 	if (xdr->iov)
1115 		xdr->iov->iov_len += nbytes;
1116 	else
1117 		xdr->buf->page_len += nbytes;
1118 	xdr->buf->len += nbytes;
1119 	return p;
1120 }
1121 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1122 
1123 /**
1124  * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1125  * @xdr: pointer to xdr_stream
1126  * @nbytes: number of bytes to reserve
1127  *
1128  * The size argument passed to xdr_reserve_space() is determined based
1129  * on the number of bytes remaining in the current page to avoid
1130  * invalidating iov_base pointers when xdr_commit_encode() is called.
1131  *
1132  * Return values:
1133  *   %0: success
1134  *   %-EMSGSIZE: not enough space is available in @xdr
1135  */
xdr_reserve_space_vec(struct xdr_stream * xdr,size_t nbytes)1136 int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes)
1137 {
1138 	size_t thislen;
1139 	__be32 *p;
1140 
1141 	/*
1142 	 * svcrdma requires every READ payload to start somewhere
1143 	 * in xdr->pages.
1144 	 */
1145 	if (xdr->iov == xdr->buf->head) {
1146 		xdr->iov = NULL;
1147 		xdr->end = xdr->p;
1148 	}
1149 
1150 	/* XXX: Let's find a way to make this more efficient */
1151 	while (nbytes) {
1152 		thislen = xdr->buf->page_len % PAGE_SIZE;
1153 		thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1154 
1155 		p = xdr_reserve_space(xdr, thislen);
1156 		if (!p)
1157 			return -EMSGSIZE;
1158 
1159 		nbytes -= thislen;
1160 	}
1161 
1162 	return 0;
1163 }
1164 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1165 
1166 /**
1167  * xdr_truncate_encode - truncate an encode buffer
1168  * @xdr: pointer to xdr_stream
1169  * @len: new length of buffer
1170  *
1171  * Truncates the xdr stream, so that xdr->buf->len == len,
1172  * and xdr->p points at offset len from the start of the buffer, and
1173  * head, tail, and page lengths are adjusted to correspond.
1174  *
1175  * If this means moving xdr->p to a different buffer, we assume that
1176  * the end pointer should be set to the end of the current page,
1177  * except in the case of the head buffer when we assume the head
1178  * buffer's current length represents the end of the available buffer.
1179  *
1180  * This is *not* safe to use on a buffer that already has inlined page
1181  * cache pages (as in a zero-copy server read reply), except for the
1182  * simple case of truncating from one position in the tail to another.
1183  *
1184  */
xdr_truncate_encode(struct xdr_stream * xdr,size_t len)1185 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1186 {
1187 	struct xdr_buf *buf = xdr->buf;
1188 	struct kvec *head = buf->head;
1189 	struct kvec *tail = buf->tail;
1190 	int fraglen;
1191 	int new;
1192 
1193 	if (len > buf->len) {
1194 		WARN_ON_ONCE(1);
1195 		return;
1196 	}
1197 	xdr_commit_encode(xdr);
1198 
1199 	fraglen = min_t(int, buf->len - len, tail->iov_len);
1200 	tail->iov_len -= fraglen;
1201 	buf->len -= fraglen;
1202 	if (tail->iov_len) {
1203 		xdr->p = tail->iov_base + tail->iov_len;
1204 		WARN_ON_ONCE(!xdr->end);
1205 		WARN_ON_ONCE(!xdr->iov);
1206 		return;
1207 	}
1208 	WARN_ON_ONCE(fraglen);
1209 	fraglen = min_t(int, buf->len - len, buf->page_len);
1210 	buf->page_len -= fraglen;
1211 	buf->len -= fraglen;
1212 
1213 	new = buf->page_base + buf->page_len;
1214 
1215 	xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1216 
1217 	if (buf->page_len) {
1218 		xdr->p = page_address(*xdr->page_ptr);
1219 		xdr->end = (void *)xdr->p + PAGE_SIZE;
1220 		xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1221 		WARN_ON_ONCE(xdr->iov);
1222 		return;
1223 	}
1224 	if (fraglen)
1225 		xdr->end = head->iov_base + head->iov_len;
1226 	/* (otherwise assume xdr->end is already set) */
1227 	xdr->page_ptr--;
1228 	head->iov_len = len;
1229 	buf->len = len;
1230 	xdr->p = head->iov_base + head->iov_len;
1231 	xdr->iov = buf->head;
1232 }
1233 EXPORT_SYMBOL(xdr_truncate_encode);
1234 
1235 /**
1236  * xdr_truncate_decode - Truncate a decoding stream
1237  * @xdr: pointer to struct xdr_stream
1238  * @len: Number of bytes to remove
1239  *
1240  */
xdr_truncate_decode(struct xdr_stream * xdr,size_t len)1241 void xdr_truncate_decode(struct xdr_stream *xdr, size_t len)
1242 {
1243 	unsigned int nbytes = xdr_align_size(len);
1244 
1245 	xdr->buf->len -= nbytes;
1246 	xdr->nwords -= XDR_QUADLEN(nbytes);
1247 }
1248 EXPORT_SYMBOL_GPL(xdr_truncate_decode);
1249 
1250 /**
1251  * xdr_restrict_buflen - decrease available buffer space
1252  * @xdr: pointer to xdr_stream
1253  * @newbuflen: new maximum number of bytes available
1254  *
1255  * Adjust our idea of how much space is available in the buffer.
1256  * If we've already used too much space in the buffer, returns -1.
1257  * If the available space is already smaller than newbuflen, returns 0
1258  * and does nothing.  Otherwise, adjusts xdr->buf->buflen to newbuflen
1259  * and ensures xdr->end is set at most offset newbuflen from the start
1260  * of the buffer.
1261  */
xdr_restrict_buflen(struct xdr_stream * xdr,int newbuflen)1262 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1263 {
1264 	struct xdr_buf *buf = xdr->buf;
1265 	int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1266 	int end_offset = buf->len + left_in_this_buf;
1267 
1268 	if (newbuflen < 0 || newbuflen < buf->len)
1269 		return -1;
1270 	if (newbuflen > buf->buflen)
1271 		return 0;
1272 	if (newbuflen < end_offset)
1273 		xdr->end = (void *)xdr->end + newbuflen - end_offset;
1274 	buf->buflen = newbuflen;
1275 	return 0;
1276 }
1277 EXPORT_SYMBOL(xdr_restrict_buflen);
1278 
1279 /**
1280  * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1281  * @xdr: pointer to xdr_stream
1282  * @pages: array of pages to insert
1283  * @base: starting offset of first data byte in @pages
1284  * @len: number of data bytes in @pages to insert
1285  *
1286  * After the @pages are added, the tail iovec is instantiated pointing to
1287  * end of the head buffer, and the stream is set up to encode subsequent
1288  * items into the tail.
1289  */
xdr_write_pages(struct xdr_stream * xdr,struct page ** pages,unsigned int base,unsigned int len)1290 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1291 		 unsigned int len)
1292 {
1293 	struct xdr_buf *buf = xdr->buf;
1294 	struct kvec *tail = buf->tail;
1295 
1296 	buf->pages = pages;
1297 	buf->page_base = base;
1298 	buf->page_len = len;
1299 
1300 	tail->iov_base = xdr->p;
1301 	tail->iov_len = 0;
1302 	xdr->iov = tail;
1303 
1304 	if (len & 3) {
1305 		unsigned int pad = 4 - (len & 3);
1306 
1307 		BUG_ON(xdr->p >= xdr->end);
1308 		tail->iov_base = (char *)xdr->p + (len & 3);
1309 		tail->iov_len += pad;
1310 		len += pad;
1311 		*xdr->p++ = 0;
1312 	}
1313 	buf->buflen += len;
1314 	buf->len += len;
1315 }
1316 EXPORT_SYMBOL_GPL(xdr_write_pages);
1317 
xdr_set_iov(struct xdr_stream * xdr,struct kvec * iov,unsigned int base,unsigned int len)1318 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1319 				unsigned int base, unsigned int len)
1320 {
1321 	if (len > iov->iov_len)
1322 		len = iov->iov_len;
1323 	if (unlikely(base > len))
1324 		base = len;
1325 	xdr->p = (__be32*)(iov->iov_base + base);
1326 	xdr->end = (__be32*)(iov->iov_base + len);
1327 	xdr->iov = iov;
1328 	xdr->page_ptr = NULL;
1329 	return len - base;
1330 }
1331 
xdr_set_tail_base(struct xdr_stream * xdr,unsigned int base,unsigned int len)1332 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1333 				      unsigned int base, unsigned int len)
1334 {
1335 	struct xdr_buf *buf = xdr->buf;
1336 
1337 	xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1338 	return xdr_set_iov(xdr, buf->tail, base, len);
1339 }
1340 
xdr_stream_unmap_current_page(struct xdr_stream * xdr)1341 static void xdr_stream_unmap_current_page(struct xdr_stream *xdr)
1342 {
1343 	if (xdr->page_kaddr) {
1344 		kunmap_local(xdr->page_kaddr);
1345 		xdr->page_kaddr = NULL;
1346 	}
1347 }
1348 
xdr_set_page_base(struct xdr_stream * xdr,unsigned int base,unsigned int len)1349 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1350 				      unsigned int base, unsigned int len)
1351 {
1352 	unsigned int pgnr;
1353 	unsigned int maxlen;
1354 	unsigned int pgoff;
1355 	unsigned int pgend;
1356 	void *kaddr;
1357 
1358 	maxlen = xdr->buf->page_len;
1359 	if (base >= maxlen)
1360 		return 0;
1361 	else
1362 		maxlen -= base;
1363 	if (len > maxlen)
1364 		len = maxlen;
1365 
1366 	xdr_stream_unmap_current_page(xdr);
1367 	xdr_stream_page_set_pos(xdr, base);
1368 	base += xdr->buf->page_base;
1369 
1370 	pgnr = base >> PAGE_SHIFT;
1371 	xdr->page_ptr = &xdr->buf->pages[pgnr];
1372 
1373 	if (PageHighMem(*xdr->page_ptr)) {
1374 		xdr->page_kaddr = kmap_local_page(*xdr->page_ptr);
1375 		kaddr = xdr->page_kaddr;
1376 	} else
1377 		kaddr = page_address(*xdr->page_ptr);
1378 
1379 	pgoff = base & ~PAGE_MASK;
1380 	xdr->p = (__be32*)(kaddr + pgoff);
1381 
1382 	pgend = pgoff + len;
1383 	if (pgend > PAGE_SIZE)
1384 		pgend = PAGE_SIZE;
1385 	xdr->end = (__be32*)(kaddr + pgend);
1386 	xdr->iov = NULL;
1387 	return len;
1388 }
1389 
xdr_set_page(struct xdr_stream * xdr,unsigned int base,unsigned int len)1390 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1391 			 unsigned int len)
1392 {
1393 	if (xdr_set_page_base(xdr, base, len) == 0) {
1394 		base -= xdr->buf->page_len;
1395 		xdr_set_tail_base(xdr, base, len);
1396 	}
1397 }
1398 
xdr_set_next_page(struct xdr_stream * xdr)1399 static void xdr_set_next_page(struct xdr_stream *xdr)
1400 {
1401 	unsigned int newbase;
1402 
1403 	newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1404 	newbase -= xdr->buf->page_base;
1405 	if (newbase < xdr->buf->page_len)
1406 		xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1407 	else
1408 		xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1409 }
1410 
xdr_set_next_buffer(struct xdr_stream * xdr)1411 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1412 {
1413 	if (xdr->page_ptr != NULL)
1414 		xdr_set_next_page(xdr);
1415 	else if (xdr->iov == xdr->buf->head)
1416 		xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1417 	return xdr->p != xdr->end;
1418 }
1419 
1420 /**
1421  * xdr_init_decode - Initialize an xdr_stream for decoding data.
1422  * @xdr: pointer to xdr_stream struct
1423  * @buf: pointer to XDR buffer from which to decode data
1424  * @p: current pointer inside XDR buffer
1425  * @rqst: pointer to controlling rpc_rqst, for debugging
1426  */
xdr_init_decode(struct xdr_stream * xdr,struct xdr_buf * buf,__be32 * p,struct rpc_rqst * rqst)1427 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1428 		     struct rpc_rqst *rqst)
1429 {
1430 	xdr->buf = buf;
1431 	xdr->page_kaddr = NULL;
1432 	xdr_reset_scratch_buffer(xdr);
1433 	xdr->nwords = XDR_QUADLEN(buf->len);
1434 	if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1435 	    xdr_set_page_base(xdr, 0, buf->len) == 0)
1436 		xdr_set_iov(xdr, buf->tail, 0, buf->len);
1437 	if (p != NULL && p > xdr->p && xdr->end >= p) {
1438 		xdr->nwords -= p - xdr->p;
1439 		xdr->p = p;
1440 	}
1441 	xdr->rqst = rqst;
1442 }
1443 EXPORT_SYMBOL_GPL(xdr_init_decode);
1444 
1445 /**
1446  * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1447  * @xdr: pointer to xdr_stream struct
1448  * @buf: pointer to XDR buffer from which to decode data
1449  * @pages: list of pages to decode into
1450  * @len: length in bytes of buffer in pages
1451  */
xdr_init_decode_pages(struct xdr_stream * xdr,struct xdr_buf * buf,struct page ** pages,unsigned int len)1452 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1453 			   struct page **pages, unsigned int len)
1454 {
1455 	memset(buf, 0, sizeof(*buf));
1456 	buf->pages =  pages;
1457 	buf->page_len =  len;
1458 	buf->buflen =  len;
1459 	buf->len = len;
1460 	xdr_init_decode(xdr, buf, NULL, NULL);
1461 }
1462 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1463 
1464 /**
1465  * xdr_finish_decode - Clean up the xdr_stream after decoding data.
1466  * @xdr: pointer to xdr_stream struct
1467  */
xdr_finish_decode(struct xdr_stream * xdr)1468 void xdr_finish_decode(struct xdr_stream *xdr)
1469 {
1470 	xdr_stream_unmap_current_page(xdr);
1471 }
1472 EXPORT_SYMBOL(xdr_finish_decode);
1473 
__xdr_inline_decode(struct xdr_stream * xdr,size_t nbytes)1474 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1475 {
1476 	unsigned int nwords = XDR_QUADLEN(nbytes);
1477 	__be32 *p = xdr->p;
1478 	__be32 *q = p + nwords;
1479 
1480 	if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1481 		return NULL;
1482 	xdr->p = q;
1483 	xdr->nwords -= nwords;
1484 	return p;
1485 }
1486 
xdr_copy_to_scratch(struct xdr_stream * xdr,size_t nbytes)1487 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1488 {
1489 	__be32 *p;
1490 	char *cpdest = xdr->scratch.iov_base;
1491 	size_t cplen = (char *)xdr->end - (char *)xdr->p;
1492 
1493 	if (nbytes > xdr->scratch.iov_len)
1494 		goto out_overflow;
1495 	p = __xdr_inline_decode(xdr, cplen);
1496 	if (p == NULL)
1497 		return NULL;
1498 	memcpy(cpdest, p, cplen);
1499 	if (!xdr_set_next_buffer(xdr))
1500 		goto out_overflow;
1501 	cpdest += cplen;
1502 	nbytes -= cplen;
1503 	p = __xdr_inline_decode(xdr, nbytes);
1504 	if (p == NULL)
1505 		return NULL;
1506 	memcpy(cpdest, p, nbytes);
1507 	return xdr->scratch.iov_base;
1508 out_overflow:
1509 	trace_rpc_xdr_overflow(xdr, nbytes);
1510 	return NULL;
1511 }
1512 
1513 /**
1514  * xdr_inline_decode - Retrieve XDR data to decode
1515  * @xdr: pointer to xdr_stream struct
1516  * @nbytes: number of bytes of data to decode
1517  *
1518  * Check if the input buffer is long enough to enable us to decode
1519  * 'nbytes' more bytes of data starting at the current position.
1520  * If so return the current pointer, then update the current
1521  * pointer position.
1522  */
xdr_inline_decode(struct xdr_stream * xdr,size_t nbytes)1523 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1524 {
1525 	__be32 *p;
1526 
1527 	if (unlikely(nbytes == 0))
1528 		return xdr->p;
1529 	if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1530 		goto out_overflow;
1531 	p = __xdr_inline_decode(xdr, nbytes);
1532 	if (p != NULL)
1533 		return p;
1534 	return xdr_copy_to_scratch(xdr, nbytes);
1535 out_overflow:
1536 	trace_rpc_xdr_overflow(xdr, nbytes);
1537 	return NULL;
1538 }
1539 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1540 
xdr_realign_pages(struct xdr_stream * xdr)1541 static void xdr_realign_pages(struct xdr_stream *xdr)
1542 {
1543 	struct xdr_buf *buf = xdr->buf;
1544 	struct kvec *iov = buf->head;
1545 	unsigned int cur = xdr_stream_pos(xdr);
1546 	unsigned int copied;
1547 
1548 	/* Realign pages to current pointer position */
1549 	if (iov->iov_len > cur) {
1550 		copied = xdr_shrink_bufhead(buf, cur);
1551 		trace_rpc_xdr_alignment(xdr, cur, copied);
1552 		xdr_set_page(xdr, 0, buf->page_len);
1553 	}
1554 }
1555 
xdr_align_pages(struct xdr_stream * xdr,unsigned int len)1556 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1557 {
1558 	struct xdr_buf *buf = xdr->buf;
1559 	unsigned int nwords = XDR_QUADLEN(len);
1560 	unsigned int copied;
1561 
1562 	if (xdr->nwords == 0)
1563 		return 0;
1564 
1565 	xdr_realign_pages(xdr);
1566 	if (nwords > xdr->nwords) {
1567 		nwords = xdr->nwords;
1568 		len = nwords << 2;
1569 	}
1570 	if (buf->page_len <= len)
1571 		len = buf->page_len;
1572 	else if (nwords < xdr->nwords) {
1573 		/* Truncate page data and move it into the tail */
1574 		copied = xdr_shrink_pagelen(buf, len);
1575 		trace_rpc_xdr_alignment(xdr, len, copied);
1576 	}
1577 	return len;
1578 }
1579 
1580 /**
1581  * xdr_read_pages - align page-based XDR data to current pointer position
1582  * @xdr: pointer to xdr_stream struct
1583  * @len: number of bytes of page data
1584  *
1585  * Moves data beyond the current pointer position from the XDR head[] buffer
1586  * into the page list. Any data that lies beyond current position + @len
1587  * bytes is moved into the XDR tail[]. The xdr_stream current position is
1588  * then advanced past that data to align to the next XDR object in the tail.
1589  *
1590  * Returns the number of XDR encoded bytes now contained in the pages
1591  */
xdr_read_pages(struct xdr_stream * xdr,unsigned int len)1592 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1593 {
1594 	unsigned int nwords = XDR_QUADLEN(len);
1595 	unsigned int base, end, pglen;
1596 
1597 	pglen = xdr_align_pages(xdr, nwords << 2);
1598 	if (pglen == 0)
1599 		return 0;
1600 
1601 	base = (nwords << 2) - pglen;
1602 	end = xdr_stream_remaining(xdr) - pglen;
1603 
1604 	xdr_set_tail_base(xdr, base, end);
1605 	return len <= pglen ? len : pglen;
1606 }
1607 EXPORT_SYMBOL_GPL(xdr_read_pages);
1608 
1609 /**
1610  * xdr_set_pagelen - Sets the length of the XDR pages
1611  * @xdr: pointer to xdr_stream struct
1612  * @len: new length of the XDR page data
1613  *
1614  * Either grows or shrinks the length of the xdr pages by setting pagelen to
1615  * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
1616  * when growing any data beyond the current pointer is moved into the tail.
1617  *
1618  * Returns True if the operation was successful, and False otherwise.
1619  */
xdr_set_pagelen(struct xdr_stream * xdr,unsigned int len)1620 void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
1621 {
1622 	struct xdr_buf *buf = xdr->buf;
1623 	size_t remaining = xdr_stream_remaining(xdr);
1624 	size_t base = 0;
1625 
1626 	if (len < buf->page_len) {
1627 		base = buf->page_len - len;
1628 		xdr_shrink_pagelen(buf, len);
1629 	} else {
1630 		xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
1631 					 buf->page_len, remaining);
1632 		if (len > buf->page_len)
1633 			xdr_buf_try_expand(buf, len - buf->page_len);
1634 	}
1635 	xdr_set_tail_base(xdr, base, remaining);
1636 }
1637 EXPORT_SYMBOL_GPL(xdr_set_pagelen);
1638 
1639 /**
1640  * xdr_enter_page - decode data from the XDR page
1641  * @xdr: pointer to xdr_stream struct
1642  * @len: number of bytes of page data
1643  *
1644  * Moves data beyond the current pointer position from the XDR head[] buffer
1645  * into the page list. Any data that lies beyond current position + "len"
1646  * bytes is moved into the XDR tail[]. The current pointer is then
1647  * repositioned at the beginning of the first XDR page.
1648  */
xdr_enter_page(struct xdr_stream * xdr,unsigned int len)1649 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1650 {
1651 	len = xdr_align_pages(xdr, len);
1652 	/*
1653 	 * Position current pointer at beginning of tail, and
1654 	 * set remaining message length.
1655 	 */
1656 	if (len != 0)
1657 		xdr_set_page_base(xdr, 0, len);
1658 }
1659 EXPORT_SYMBOL_GPL(xdr_enter_page);
1660 
1661 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1662 
xdr_buf_from_iov(const struct kvec * iov,struct xdr_buf * buf)1663 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1664 {
1665 	buf->head[0] = *iov;
1666 	buf->tail[0] = empty_iov;
1667 	buf->page_len = 0;
1668 	buf->buflen = buf->len = iov->iov_len;
1669 }
1670 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1671 
1672 /**
1673  * xdr_buf_subsegment - set subbuf to a portion of buf
1674  * @buf: an xdr buffer
1675  * @subbuf: the result buffer
1676  * @base: beginning of range in bytes
1677  * @len: length of range in bytes
1678  *
1679  * sets @subbuf to an xdr buffer representing the portion of @buf of
1680  * length @len starting at offset @base.
1681  *
1682  * @buf and @subbuf may be pointers to the same struct xdr_buf.
1683  *
1684  * Returns -1 if base or length are out of bounds.
1685  */
xdr_buf_subsegment(const struct xdr_buf * buf,struct xdr_buf * subbuf,unsigned int base,unsigned int len)1686 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1687 		       unsigned int base, unsigned int len)
1688 {
1689 	subbuf->buflen = subbuf->len = len;
1690 	if (base < buf->head[0].iov_len) {
1691 		subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1692 		subbuf->head[0].iov_len = min_t(unsigned int, len,
1693 						buf->head[0].iov_len - base);
1694 		len -= subbuf->head[0].iov_len;
1695 		base = 0;
1696 	} else {
1697 		base -= buf->head[0].iov_len;
1698 		subbuf->head[0].iov_base = buf->head[0].iov_base;
1699 		subbuf->head[0].iov_len = 0;
1700 	}
1701 
1702 	if (base < buf->page_len) {
1703 		subbuf->page_len = min(buf->page_len - base, len);
1704 		base += buf->page_base;
1705 		subbuf->page_base = base & ~PAGE_MASK;
1706 		subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1707 		len -= subbuf->page_len;
1708 		base = 0;
1709 	} else {
1710 		base -= buf->page_len;
1711 		subbuf->pages = buf->pages;
1712 		subbuf->page_base = 0;
1713 		subbuf->page_len = 0;
1714 	}
1715 
1716 	if (base < buf->tail[0].iov_len) {
1717 		subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1718 		subbuf->tail[0].iov_len = min_t(unsigned int, len,
1719 						buf->tail[0].iov_len - base);
1720 		len -= subbuf->tail[0].iov_len;
1721 		base = 0;
1722 	} else {
1723 		base -= buf->tail[0].iov_len;
1724 		subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1725 		subbuf->tail[0].iov_len = 0;
1726 	}
1727 
1728 	if (base || len)
1729 		return -1;
1730 	return 0;
1731 }
1732 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1733 
1734 /**
1735  * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1736  * @xdr: an xdr_stream set up for decoding
1737  * @subbuf: the result buffer
1738  * @nbytes: length of @xdr to extract, in bytes
1739  *
1740  * Sets up @subbuf to represent a portion of @xdr. The portion
1741  * starts at the current offset in @xdr, and extends for a length
1742  * of @nbytes. If this is successful, @xdr is advanced to the next
1743  * XDR data item following that portion.
1744  *
1745  * Return values:
1746  *   %true: @subbuf has been initialized, and @xdr has been advanced.
1747  *   %false: a bounds error has occurred
1748  */
xdr_stream_subsegment(struct xdr_stream * xdr,struct xdr_buf * subbuf,unsigned int nbytes)1749 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1750 			   unsigned int nbytes)
1751 {
1752 	unsigned int start = xdr_stream_pos(xdr);
1753 	unsigned int remaining, len;
1754 
1755 	/* Extract @subbuf and bounds-check the fn arguments */
1756 	if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1757 		return false;
1758 
1759 	/* Advance @xdr by @nbytes */
1760 	for (remaining = nbytes; remaining;) {
1761 		if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1762 			return false;
1763 
1764 		len = (char *)xdr->end - (char *)xdr->p;
1765 		if (remaining <= len) {
1766 			xdr->p = (__be32 *)((char *)xdr->p +
1767 					(remaining + xdr_pad_size(nbytes)));
1768 			break;
1769 		}
1770 
1771 		xdr->p = (__be32 *)((char *)xdr->p + len);
1772 		xdr->end = xdr->p;
1773 		remaining -= len;
1774 	}
1775 
1776 	xdr_stream_set_pos(xdr, start + nbytes);
1777 	return true;
1778 }
1779 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1780 
1781 /**
1782  * xdr_stream_move_subsegment - Move part of a stream to another position
1783  * @xdr: the source xdr_stream
1784  * @offset: the source offset of the segment
1785  * @target: the target offset of the segment
1786  * @length: the number of bytes to move
1787  *
1788  * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
1789  * anything in its space. Returns the number of bytes in the segment.
1790  */
xdr_stream_move_subsegment(struct xdr_stream * xdr,unsigned int offset,unsigned int target,unsigned int length)1791 unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
1792 					unsigned int target, unsigned int length)
1793 {
1794 	struct xdr_buf buf;
1795 	unsigned int shift;
1796 
1797 	if (offset < target) {
1798 		shift = target - offset;
1799 		if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
1800 			return 0;
1801 		xdr_buf_head_shift_right(&buf, 0, length, shift);
1802 	} else if (offset > target) {
1803 		shift = offset - target;
1804 		if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
1805 			return 0;
1806 		xdr_buf_head_shift_left(&buf, shift, length, shift);
1807 	}
1808 	return length;
1809 }
1810 EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
1811 
1812 /**
1813  * xdr_stream_zero - zero out a portion of an xdr_stream
1814  * @xdr: an xdr_stream to zero out
1815  * @offset: the starting point in the stream
1816  * @length: the number of bytes to zero
1817  */
xdr_stream_zero(struct xdr_stream * xdr,unsigned int offset,unsigned int length)1818 unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
1819 			     unsigned int length)
1820 {
1821 	struct xdr_buf buf;
1822 
1823 	if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
1824 		return 0;
1825 	if (buf.head[0].iov_len)
1826 		xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
1827 	if (buf.page_len > 0)
1828 		xdr_buf_pages_zero(&buf, 0, buf.page_len);
1829 	if (buf.tail[0].iov_len)
1830 		xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
1831 	return length;
1832 }
1833 EXPORT_SYMBOL_GPL(xdr_stream_zero);
1834 
1835 /**
1836  * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1837  * @buf: buf to be trimmed
1838  * @len: number of bytes to reduce "buf" by
1839  *
1840  * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1841  * that it's possible that we'll trim less than that amount if the xdr_buf is
1842  * too small, or if (for instance) it's all in the head and the parser has
1843  * already read too far into it.
1844  */
xdr_buf_trim(struct xdr_buf * buf,unsigned int len)1845 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1846 {
1847 	size_t cur;
1848 	unsigned int trim = len;
1849 
1850 	if (buf->tail[0].iov_len) {
1851 		cur = min_t(size_t, buf->tail[0].iov_len, trim);
1852 		buf->tail[0].iov_len -= cur;
1853 		trim -= cur;
1854 		if (!trim)
1855 			goto fix_len;
1856 	}
1857 
1858 	if (buf->page_len) {
1859 		cur = min_t(unsigned int, buf->page_len, trim);
1860 		buf->page_len -= cur;
1861 		trim -= cur;
1862 		if (!trim)
1863 			goto fix_len;
1864 	}
1865 
1866 	if (buf->head[0].iov_len) {
1867 		cur = min_t(size_t, buf->head[0].iov_len, trim);
1868 		buf->head[0].iov_len -= cur;
1869 		trim -= cur;
1870 	}
1871 fix_len:
1872 	buf->len -= (len - trim);
1873 }
1874 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1875 
__read_bytes_from_xdr_buf(const struct xdr_buf * subbuf,void * obj,unsigned int len)1876 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1877 				      void *obj, unsigned int len)
1878 {
1879 	unsigned int this_len;
1880 
1881 	this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1882 	memcpy(obj, subbuf->head[0].iov_base, this_len);
1883 	len -= this_len;
1884 	obj += this_len;
1885 	this_len = min_t(unsigned int, len, subbuf->page_len);
1886 	_copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1887 	len -= this_len;
1888 	obj += this_len;
1889 	this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1890 	memcpy(obj, subbuf->tail[0].iov_base, this_len);
1891 }
1892 
1893 /* obj is assumed to point to allocated memory of size at least len: */
read_bytes_from_xdr_buf(const struct xdr_buf * buf,unsigned int base,void * obj,unsigned int len)1894 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1895 			    void *obj, unsigned int len)
1896 {
1897 	struct xdr_buf subbuf;
1898 	int status;
1899 
1900 	status = xdr_buf_subsegment(buf, &subbuf, base, len);
1901 	if (status != 0)
1902 		return status;
1903 	__read_bytes_from_xdr_buf(&subbuf, obj, len);
1904 	return 0;
1905 }
1906 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1907 
__write_bytes_to_xdr_buf(const struct xdr_buf * subbuf,void * obj,unsigned int len)1908 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1909 				     void *obj, unsigned int len)
1910 {
1911 	unsigned int this_len;
1912 
1913 	this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1914 	memcpy(subbuf->head[0].iov_base, obj, this_len);
1915 	len -= this_len;
1916 	obj += this_len;
1917 	this_len = min_t(unsigned int, len, subbuf->page_len);
1918 	_copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1919 	len -= this_len;
1920 	obj += this_len;
1921 	this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1922 	memcpy(subbuf->tail[0].iov_base, obj, this_len);
1923 }
1924 
1925 /* obj is assumed to point to allocated memory of size at least len: */
write_bytes_to_xdr_buf(const struct xdr_buf * buf,unsigned int base,void * obj,unsigned int len)1926 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1927 			   void *obj, unsigned int len)
1928 {
1929 	struct xdr_buf subbuf;
1930 	int status;
1931 
1932 	status = xdr_buf_subsegment(buf, &subbuf, base, len);
1933 	if (status != 0)
1934 		return status;
1935 	__write_bytes_to_xdr_buf(&subbuf, obj, len);
1936 	return 0;
1937 }
1938 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1939 
xdr_decode_word(const struct xdr_buf * buf,unsigned int base,u32 * obj)1940 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1941 {
1942 	__be32	raw;
1943 	int	status;
1944 
1945 	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1946 	if (status)
1947 		return status;
1948 	*obj = be32_to_cpu(raw);
1949 	return 0;
1950 }
1951 EXPORT_SYMBOL_GPL(xdr_decode_word);
1952 
xdr_encode_word(const struct xdr_buf * buf,unsigned int base,u32 obj)1953 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1954 {
1955 	__be32	raw = cpu_to_be32(obj);
1956 
1957 	return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1958 }
1959 EXPORT_SYMBOL_GPL(xdr_encode_word);
1960 
1961 /* Returns 0 on success, or else a negative error code. */
xdr_xcode_array2(const struct xdr_buf * buf,unsigned int base,struct xdr_array2_desc * desc,int encode)1962 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1963 			    struct xdr_array2_desc *desc, int encode)
1964 {
1965 	char *elem = NULL, *c;
1966 	unsigned int copied = 0, todo, avail_here;
1967 	struct page **ppages = NULL;
1968 	int err;
1969 
1970 	if (encode) {
1971 		if (xdr_encode_word(buf, base, desc->array_len) != 0)
1972 			return -EINVAL;
1973 	} else {
1974 		if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1975 		    desc->array_len > desc->array_maxlen ||
1976 		    (unsigned long) base + 4 + desc->array_len *
1977 				    desc->elem_size > buf->len)
1978 			return -EINVAL;
1979 	}
1980 	base += 4;
1981 
1982 	if (!desc->xcode)
1983 		return 0;
1984 
1985 	todo = desc->array_len * desc->elem_size;
1986 
1987 	/* process head */
1988 	if (todo && base < buf->head->iov_len) {
1989 		c = buf->head->iov_base + base;
1990 		avail_here = min_t(unsigned int, todo,
1991 				   buf->head->iov_len - base);
1992 		todo -= avail_here;
1993 
1994 		while (avail_here >= desc->elem_size) {
1995 			err = desc->xcode(desc, c);
1996 			if (err)
1997 				goto out;
1998 			c += desc->elem_size;
1999 			avail_here -= desc->elem_size;
2000 		}
2001 		if (avail_here) {
2002 			if (!elem) {
2003 				elem = kmalloc(desc->elem_size, GFP_KERNEL);
2004 				err = -ENOMEM;
2005 				if (!elem)
2006 					goto out;
2007 			}
2008 			if (encode) {
2009 				err = desc->xcode(desc, elem);
2010 				if (err)
2011 					goto out;
2012 				memcpy(c, elem, avail_here);
2013 			} else
2014 				memcpy(elem, c, avail_here);
2015 			copied = avail_here;
2016 		}
2017 		base = buf->head->iov_len;  /* align to start of pages */
2018 	}
2019 
2020 	/* process pages array */
2021 	base -= buf->head->iov_len;
2022 	if (todo && base < buf->page_len) {
2023 		unsigned int avail_page;
2024 
2025 		avail_here = min(todo, buf->page_len - base);
2026 		todo -= avail_here;
2027 
2028 		base += buf->page_base;
2029 		ppages = buf->pages + (base >> PAGE_SHIFT);
2030 		base &= ~PAGE_MASK;
2031 		avail_page = min_t(unsigned int, PAGE_SIZE - base,
2032 					avail_here);
2033 		c = kmap(*ppages) + base;
2034 
2035 		while (avail_here) {
2036 			avail_here -= avail_page;
2037 			if (copied || avail_page < desc->elem_size) {
2038 				unsigned int l = min(avail_page,
2039 					desc->elem_size - copied);
2040 				if (!elem) {
2041 					elem = kmalloc(desc->elem_size,
2042 						       GFP_KERNEL);
2043 					err = -ENOMEM;
2044 					if (!elem)
2045 						goto out;
2046 				}
2047 				if (encode) {
2048 					if (!copied) {
2049 						err = desc->xcode(desc, elem);
2050 						if (err)
2051 							goto out;
2052 					}
2053 					memcpy(c, elem + copied, l);
2054 					copied += l;
2055 					if (copied == desc->elem_size)
2056 						copied = 0;
2057 				} else {
2058 					memcpy(elem + copied, c, l);
2059 					copied += l;
2060 					if (copied == desc->elem_size) {
2061 						err = desc->xcode(desc, elem);
2062 						if (err)
2063 							goto out;
2064 						copied = 0;
2065 					}
2066 				}
2067 				avail_page -= l;
2068 				c += l;
2069 			}
2070 			while (avail_page >= desc->elem_size) {
2071 				err = desc->xcode(desc, c);
2072 				if (err)
2073 					goto out;
2074 				c += desc->elem_size;
2075 				avail_page -= desc->elem_size;
2076 			}
2077 			if (avail_page) {
2078 				unsigned int l = min(avail_page,
2079 					    desc->elem_size - copied);
2080 				if (!elem) {
2081 					elem = kmalloc(desc->elem_size,
2082 						       GFP_KERNEL);
2083 					err = -ENOMEM;
2084 					if (!elem)
2085 						goto out;
2086 				}
2087 				if (encode) {
2088 					if (!copied) {
2089 						err = desc->xcode(desc, elem);
2090 						if (err)
2091 							goto out;
2092 					}
2093 					memcpy(c, elem + copied, l);
2094 					copied += l;
2095 					if (copied == desc->elem_size)
2096 						copied = 0;
2097 				} else {
2098 					memcpy(elem + copied, c, l);
2099 					copied += l;
2100 					if (copied == desc->elem_size) {
2101 						err = desc->xcode(desc, elem);
2102 						if (err)
2103 							goto out;
2104 						copied = 0;
2105 					}
2106 				}
2107 			}
2108 			if (avail_here) {
2109 				kunmap(*ppages);
2110 				ppages++;
2111 				c = kmap(*ppages);
2112 			}
2113 
2114 			avail_page = min(avail_here,
2115 				 (unsigned int) PAGE_SIZE);
2116 		}
2117 		base = buf->page_len;  /* align to start of tail */
2118 	}
2119 
2120 	/* process tail */
2121 	base -= buf->page_len;
2122 	if (todo) {
2123 		c = buf->tail->iov_base + base;
2124 		if (copied) {
2125 			unsigned int l = desc->elem_size - copied;
2126 
2127 			if (encode)
2128 				memcpy(c, elem + copied, l);
2129 			else {
2130 				memcpy(elem + copied, c, l);
2131 				err = desc->xcode(desc, elem);
2132 				if (err)
2133 					goto out;
2134 			}
2135 			todo -= l;
2136 			c += l;
2137 		}
2138 		while (todo) {
2139 			err = desc->xcode(desc, c);
2140 			if (err)
2141 				goto out;
2142 			c += desc->elem_size;
2143 			todo -= desc->elem_size;
2144 		}
2145 	}
2146 	err = 0;
2147 
2148 out:
2149 	kfree(elem);
2150 	if (ppages)
2151 		kunmap(*ppages);
2152 	return err;
2153 }
2154 
xdr_decode_array2(const struct xdr_buf * buf,unsigned int base,struct xdr_array2_desc * desc)2155 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2156 		      struct xdr_array2_desc *desc)
2157 {
2158 	if (base >= buf->len)
2159 		return -EINVAL;
2160 
2161 	return xdr_xcode_array2(buf, base, desc, 0);
2162 }
2163 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2164 
xdr_encode_array2(const struct xdr_buf * buf,unsigned int base,struct xdr_array2_desc * desc)2165 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2166 		      struct xdr_array2_desc *desc)
2167 {
2168 	if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2169 	    buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2170 		return -EINVAL;
2171 
2172 	return xdr_xcode_array2(buf, base, desc, 1);
2173 }
2174 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2175 
xdr_process_buf(const struct xdr_buf * buf,unsigned int offset,unsigned int len,int (* actor)(struct scatterlist *,void *),void * data)2176 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2177 		    unsigned int len,
2178 		    int (*actor)(struct scatterlist *, void *), void *data)
2179 {
2180 	int i, ret = 0;
2181 	unsigned int page_len, thislen, page_offset;
2182 	struct scatterlist      sg[1];
2183 
2184 	sg_init_table(sg, 1);
2185 
2186 	if (offset >= buf->head[0].iov_len) {
2187 		offset -= buf->head[0].iov_len;
2188 	} else {
2189 		thislen = buf->head[0].iov_len - offset;
2190 		if (thislen > len)
2191 			thislen = len;
2192 		sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2193 		ret = actor(sg, data);
2194 		if (ret)
2195 			goto out;
2196 		offset = 0;
2197 		len -= thislen;
2198 	}
2199 	if (len == 0)
2200 		goto out;
2201 
2202 	if (offset >= buf->page_len) {
2203 		offset -= buf->page_len;
2204 	} else {
2205 		page_len = buf->page_len - offset;
2206 		if (page_len > len)
2207 			page_len = len;
2208 		len -= page_len;
2209 		page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2210 		i = (offset + buf->page_base) >> PAGE_SHIFT;
2211 		thislen = PAGE_SIZE - page_offset;
2212 		do {
2213 			if (thislen > page_len)
2214 				thislen = page_len;
2215 			sg_set_page(sg, buf->pages[i], thislen, page_offset);
2216 			ret = actor(sg, data);
2217 			if (ret)
2218 				goto out;
2219 			page_len -= thislen;
2220 			i++;
2221 			page_offset = 0;
2222 			thislen = PAGE_SIZE;
2223 		} while (page_len != 0);
2224 		offset = 0;
2225 	}
2226 	if (len == 0)
2227 		goto out;
2228 	if (offset < buf->tail[0].iov_len) {
2229 		thislen = buf->tail[0].iov_len - offset;
2230 		if (thislen > len)
2231 			thislen = len;
2232 		sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2233 		ret = actor(sg, data);
2234 		len -= thislen;
2235 	}
2236 	if (len != 0)
2237 		ret = -EINVAL;
2238 out:
2239 	return ret;
2240 }
2241 EXPORT_SYMBOL_GPL(xdr_process_buf);
2242 
2243 /**
2244  * xdr_stream_decode_opaque - Decode variable length opaque
2245  * @xdr: pointer to xdr_stream
2246  * @ptr: location to store opaque data
2247  * @size: size of storage buffer @ptr
2248  *
2249  * Return values:
2250  *   On success, returns size of object stored in *@ptr
2251  *   %-EBADMSG on XDR buffer overflow
2252  *   %-EMSGSIZE on overflow of storage buffer @ptr
2253  */
xdr_stream_decode_opaque(struct xdr_stream * xdr,void * ptr,size_t size)2254 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2255 {
2256 	ssize_t ret;
2257 	void *p;
2258 
2259 	ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2260 	if (ret <= 0)
2261 		return ret;
2262 	memcpy(ptr, p, ret);
2263 	return ret;
2264 }
2265 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2266 
2267 /**
2268  * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2269  * @xdr: pointer to xdr_stream
2270  * @ptr: location to store pointer to opaque data
2271  * @maxlen: maximum acceptable object size
2272  * @gfp_flags: GFP mask to use
2273  *
2274  * Return values:
2275  *   On success, returns size of object stored in *@ptr
2276  *   %-EBADMSG on XDR buffer overflow
2277  *   %-EMSGSIZE if the size of the object would exceed @maxlen
2278  *   %-ENOMEM on memory allocation failure
2279  */
xdr_stream_decode_opaque_dup(struct xdr_stream * xdr,void ** ptr,size_t maxlen,gfp_t gfp_flags)2280 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2281 		size_t maxlen, gfp_t gfp_flags)
2282 {
2283 	ssize_t ret;
2284 	void *p;
2285 
2286 	ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2287 	if (ret > 0) {
2288 		*ptr = kmemdup(p, ret, gfp_flags);
2289 		if (*ptr != NULL)
2290 			return ret;
2291 		ret = -ENOMEM;
2292 	}
2293 	*ptr = NULL;
2294 	return ret;
2295 }
2296 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2297 
2298 /**
2299  * xdr_stream_decode_string - Decode variable length string
2300  * @xdr: pointer to xdr_stream
2301  * @str: location to store string
2302  * @size: size of storage buffer @str
2303  *
2304  * Return values:
2305  *   On success, returns length of NUL-terminated string stored in *@str
2306  *   %-EBADMSG on XDR buffer overflow
2307  *   %-EMSGSIZE on overflow of storage buffer @str
2308  */
xdr_stream_decode_string(struct xdr_stream * xdr,char * str,size_t size)2309 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2310 {
2311 	ssize_t ret;
2312 	void *p;
2313 
2314 	ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2315 	if (ret > 0) {
2316 		memcpy(str, p, ret);
2317 		str[ret] = '\0';
2318 		return strlen(str);
2319 	}
2320 	*str = '\0';
2321 	return ret;
2322 }
2323 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2324 
2325 /**
2326  * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2327  * @xdr: pointer to xdr_stream
2328  * @str: location to store pointer to string
2329  * @maxlen: maximum acceptable string length
2330  * @gfp_flags: GFP mask to use
2331  *
2332  * Return values:
2333  *   On success, returns length of NUL-terminated string stored in *@ptr
2334  *   %-EBADMSG on XDR buffer overflow
2335  *   %-EMSGSIZE if the size of the string would exceed @maxlen
2336  *   %-ENOMEM on memory allocation failure
2337  */
xdr_stream_decode_string_dup(struct xdr_stream * xdr,char ** str,size_t maxlen,gfp_t gfp_flags)2338 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2339 		size_t maxlen, gfp_t gfp_flags)
2340 {
2341 	void *p;
2342 	ssize_t ret;
2343 
2344 	ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2345 	if (ret > 0) {
2346 		char *s = kmemdup_nul(p, ret, gfp_flags);
2347 		if (s != NULL) {
2348 			*str = s;
2349 			return strlen(s);
2350 		}
2351 		ret = -ENOMEM;
2352 	}
2353 	*str = NULL;
2354 	return ret;
2355 }
2356 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
2357 
2358 /**
2359  * xdr_stream_decode_opaque_auth - Decode struct opaque_auth (RFC5531 S8.2)
2360  * @xdr: pointer to xdr_stream
2361  * @flavor: location to store decoded flavor
2362  * @body: location to store decode body
2363  * @body_len: location to store length of decoded body
2364  *
2365  * Return values:
2366  *   On success, returns the number of buffer bytes consumed
2367  *   %-EBADMSG on XDR buffer overflow
2368  *   %-EMSGSIZE if the decoded size of the body field exceeds 400 octets
2369  */
xdr_stream_decode_opaque_auth(struct xdr_stream * xdr,u32 * flavor,void ** body,unsigned int * body_len)2370 ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor,
2371 				      void **body, unsigned int *body_len)
2372 {
2373 	ssize_t ret, len;
2374 
2375 	len = xdr_stream_decode_u32(xdr, flavor);
2376 	if (unlikely(len < 0))
2377 		return len;
2378 	ret = xdr_stream_decode_opaque_inline(xdr, body, RPC_MAX_AUTH_SIZE);
2379 	if (unlikely(ret < 0))
2380 		return ret;
2381 	*body_len = ret;
2382 	return len + ret;
2383 }
2384 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_auth);
2385 
2386 /**
2387  * xdr_stream_encode_opaque_auth - Encode struct opaque_auth (RFC5531 S8.2)
2388  * @xdr: pointer to xdr_stream
2389  * @flavor: verifier flavor to encode
2390  * @body: content of body to encode
2391  * @body_len: length of body to encode
2392  *
2393  * Return values:
2394  *   On success, returns length in bytes of XDR buffer consumed
2395  *   %-EBADMSG on XDR buffer overflow
2396  *   %-EMSGSIZE if the size of @body exceeds 400 octets
2397  */
xdr_stream_encode_opaque_auth(struct xdr_stream * xdr,u32 flavor,void * body,unsigned int body_len)2398 ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,
2399 				      void *body, unsigned int body_len)
2400 {
2401 	ssize_t ret, len;
2402 
2403 	if (unlikely(body_len > RPC_MAX_AUTH_SIZE))
2404 		return -EMSGSIZE;
2405 	len = xdr_stream_encode_u32(xdr, flavor);
2406 	if (unlikely(len < 0))
2407 		return len;
2408 	ret = xdr_stream_encode_opaque(xdr, body, body_len);
2409 	if (unlikely(ret < 0))
2410 		return ret;
2411 	return len + ret;
2412 }
2413 EXPORT_SYMBOL_GPL(xdr_stream_encode_opaque_auth);
2414