1 /*- 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 */ 19 20 #include <sys/cdefs.h> 21 __FBSDID("$FreeBSD$"); 22 23 #include <sys/param.h> 24 #include <sys/systm.h> 25 #include <sys/bio.h> 26 #include <sys/buf.h> 27 #include <sys/conf.h> 28 #include <sys/proc.h> 29 #include <sys/uio.h> 30 31 #include <vm/vm.h> 32 #include <vm/vm_extern.h> 33 34 int 35 physio(struct cdev *dev, struct uio *uio, int ioflag) 36 { 37 struct buf *bp; 38 struct cdevsw *csw; 39 caddr_t sa; 40 u_int iolen; 41 int error, i, mapped; 42 43 /* Keep the process UPAGES from being swapped. XXX: why ? */ 44 PHOLD(curproc); 45 46 bp = getpbuf(NULL); 47 sa = bp->b_data; 48 error = 0; 49 50 /* XXX: sanity check */ 51 if(dev->si_iosize_max < PAGE_SIZE) { 52 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 53 devtoname(dev), dev->si_iosize_max); 54 dev->si_iosize_max = DFLTPHYS; 55 } 56 57 for (i = 0; i < uio->uio_iovcnt; i++) { 58 while (uio->uio_iov[i].iov_len) { 59 bp->b_flags = 0; 60 if (uio->uio_rw == UIO_READ) { 61 bp->b_iocmd = BIO_READ; 62 curthread->td_ru.ru_inblock++; 63 } else { 64 bp->b_iocmd = BIO_WRITE; 65 curthread->td_ru.ru_oublock++; 66 } 67 bp->b_iodone = bdone; 68 bp->b_data = uio->uio_iov[i].iov_base; 69 bp->b_bcount = uio->uio_iov[i].iov_len; 70 bp->b_offset = uio->uio_offset; 71 bp->b_iooffset = uio->uio_offset; 72 bp->b_saveaddr = sa; 73 74 /* Don't exceed drivers iosize limit */ 75 if (bp->b_bcount > dev->si_iosize_max) 76 bp->b_bcount = dev->si_iosize_max; 77 78 /* 79 * Make sure the pbuf can map the request 80 * XXX: The pbuf has kvasize = MAXPHYS so a request 81 * XXX: larger than MAXPHYS - PAGE_SIZE must be 82 * XXX: page aligned or it will be fragmented. 83 */ 84 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 85 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 86 bp->b_bcount = bp->b_kvasize; 87 if (iolen != 0) 88 bp->b_bcount -= PAGE_SIZE; 89 } 90 bp->b_bufsize = bp->b_bcount; 91 92 bp->b_blkno = btodb(bp->b_offset); 93 94 csw = dev->si_devsw; 95 if (uio->uio_segflg == UIO_USERSPACE) { 96 if (csw != NULL && 97 (csw->d_flags & D_UNMAPPED_IO) != 0) 98 mapped = 0; 99 else 100 mapped = 1; 101 if (vmapbuf(bp, mapped) < 0) { 102 error = EFAULT; 103 goto doerror; 104 } 105 } 106 107 dev_strategy_csw(dev, csw, bp); 108 if (uio->uio_rw == UIO_READ) 109 bwait(bp, PRIBIO, "physrd"); 110 else 111 bwait(bp, PRIBIO, "physwr"); 112 113 if (uio->uio_segflg == UIO_USERSPACE) 114 vunmapbuf(bp); 115 iolen = bp->b_bcount - bp->b_resid; 116 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR)) 117 goto doerror; /* EOF */ 118 uio->uio_iov[i].iov_len -= iolen; 119 uio->uio_iov[i].iov_base = 120 (char *)uio->uio_iov[i].iov_base + iolen; 121 uio->uio_resid -= iolen; 122 uio->uio_offset += iolen; 123 if( bp->b_ioflags & BIO_ERROR) { 124 error = bp->b_error; 125 goto doerror; 126 } 127 } 128 } 129 doerror: 130 relpbuf(bp, NULL); 131 PRELE(curproc); 132 return (error); 133 } 134