1 /*- 2 * Copyright (c) 2008 Yahoo!, Inc. 3 * All rights reserved. 4 * Written by: John Baldwin <jhb@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, 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. Neither the name of the author nor the names of any co-contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD: src/sys/sys/sglist.h,v 1.2 2009/08/20 19:23:58 jhb Exp $ 31 */ 32 33 /* 34 * A scatter/gather list describes a group of physical address ranges. 35 * Each physical address range consists of a starting address and a 36 * length. 37 */ 38 39 #ifndef _SYS_SGLIST_H_ 40 #define _SYS_SGLIST_H_ 41 42 #ifndef _KERNEL 43 #error "This file should not be included by userland programs." 44 #endif 45 46 #include <sys/refcount.h> 47 48 struct sglist_seg { 49 vm_paddr_t ss_paddr; 50 size_t ss_len; 51 }; 52 53 struct sglist { 54 struct sglist_seg *sg_segs; 55 u_int sg_refs; 56 u_short sg_nseg; 57 u_short sg_maxseg; 58 }; 59 60 struct mbuf; 61 struct uio; 62 63 static __inline void 64 sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs) 65 { 66 67 sg->sg_segs = segs; 68 sg->sg_nseg = 0; 69 sg->sg_maxseg = maxsegs; 70 refcount_init(&sg->sg_refs, 1); 71 } 72 73 static __inline void 74 sglist_reset(struct sglist *sg) 75 { 76 77 sg->sg_nseg = 0; 78 } 79 80 static __inline struct sglist * 81 sglist_hold(struct sglist *sg) 82 { 83 84 refcount_acquire(&sg->sg_refs); 85 return (sg); 86 } 87 88 struct sglist *sglist_alloc(int nsegs, int mflags); 89 int sglist_append(struct sglist *sg, void *buf, size_t len); 90 int sglist_append_mbuf(struct sglist *sg, struct mbuf *m0); 91 int sglist_append_phys(struct sglist *sg, vm_paddr_t paddr, 92 size_t len); 93 int sglist_append_uio(struct sglist *sg, struct uio *uio); 94 int sglist_append_user(struct sglist *sg, void *buf, size_t len, 95 struct thread *td); 96 struct sglist *sglist_build(void *buf, size_t len, int mflags); 97 struct sglist *sglist_clone(struct sglist *sg, int mflags); 98 int sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid); 99 int sglist_count(void *buf, size_t len); 100 void sglist_free(struct sglist *sg); 101 int sglist_join(struct sglist *first, struct sglist *second); 102 size_t sglist_length(struct sglist *sg); 103 int sglist_slice(struct sglist *original, struct sglist **slice, 104 size_t offset, size_t length, int mflags); 105 int sglist_split(struct sglist *original, struct sglist **head, 106 size_t length, int mflags); 107 108 #endif /* !_SYS_SGLIST_H_ */ 109