[PATCH] Pull in FreeBSD's sglist
Tim
bissont at mac.com
Mon Jan 24 18:42:09 PST 2011
---
sys/conf/files | 1 +
sys/kern/subr_sglist.c | 711 ++++++++++++++++++++++++++++++++++++++++++++++++
sys/sys/sglist.h | 104 +++++++
3 files changed, 816 insertions(+), 0 deletions(-)
create mode 100644 sys/kern/subr_sglist.c
create mode 100644 sys/sys/sglist.h
diff --git a/sys/conf/files b/sys/conf/files
index 3707744..e62dcf0 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -978,6 +978,7 @@ kern/subr_alist.c standard
kern/subr_blist.c standard
kern/subr_sbuf.c standard
kern/subr_scanf.c standard
+kern/subr_sglist.c standard
kern/subr_taskqueue.c standard
kern/sys_generic.c standard
kern/sys_pipe.c standard
diff --git a/sys/kern/subr_sglist.c b/sys/kern/subr_sglist.c
new file mode 100644
index 0000000..0d1bb80
--- /dev/null
+++ b/sys/kern/subr_sglist.c
@@ -0,0 +1,711 @@
+/*-
+ * Copyright (c) 2008 Yahoo!, Inc.
+ * All rights reserved.
+ * Written by: John Baldwin <jhb at FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/proc.h>
+#include <sys/sglist.h>
+#include <sys/uio.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+
+#include <sys/ktr.h>
+
+static MALLOC_DEFINE(M_SGLIST, "sglist", "scatter/gather lists");
+
+/*
+ * Convenience macros to save the state of an sglist so it can be restored
+ * if an append attempt fails. Since sglist's only grow we only need to
+ * save the current count of segments and the length of the ending segment.
+ * Earlier segments will not be changed by an append, and the only change
+ * that can occur to the ending segment is that it can be extended.
+ */
+struct sgsave {
+ u_short sg_nseg;
+ size_t ss_len;
+};
+
+#define SGLIST_SAVE(sg, sgsave) do { \
+ (sgsave).sg_nseg = (sg)->sg_nseg; \
+ if ((sgsave).sg_nseg > 0) \
+ (sgsave).ss_len = (sg)->sg_segs[(sgsave).sg_nseg - 1].ss_len; \
+ else \
+ (sgsave).ss_len = 0; \
+} while (0)
+
+#define SGLIST_RESTORE(sg, sgsave) do { \
+ (sg)->sg_nseg = (sgsave).sg_nseg; \
+ if ((sgsave).sg_nseg > 0) \
+ (sg)->sg_segs[(sgsave).sg_nseg - 1].ss_len = (sgsave).ss_len; \
+} while (0)
+
+/*
+ * Append a single (paddr, len) to a sglist. sg is the list and ss is
+ * the current segment in the list. If we run out of segments then
+ * EFBIG will be returned.
+ */
+static __inline int
+_sglist_append_range(struct sglist *sg, struct sglist_seg **ssp,
+ vm_paddr_t paddr, size_t len)
+{
+ struct sglist_seg *ss;
+
+ ss = *ssp;
+ if (ss->ss_paddr + ss->ss_len == paddr)
+ ss->ss_len += len;
+ else {
+ if (sg->sg_nseg == sg->sg_maxseg)
+ return (EFBIG);
+ ss++;
+ ss->ss_paddr = paddr;
+ ss->ss_len = len;
+ sg->sg_nseg++;
+ *ssp = ss;
+ }
+ return (0);
+}
+
+/*
+ * Worker routine to append a virtual address range (either kernel or
+ * user) to a scatter/gather list.
+ */
+static __inline int
+_sglist_append_buf(struct sglist *sg, void *buf, size_t len, pmap_t pmap,
+ size_t *donep)
+{
+ struct sglist_seg *ss;
+ vm_offset_t vaddr, offset;
+ vm_paddr_t paddr;
+ size_t seglen;
+ int error;
+
+ if (donep)
+ *donep = 0;
+ if (len == 0)
+ return (0);
+
+ /* Do the first page. It may have an offset. */
+ vaddr = (vm_offset_t)buf;
+ offset = vaddr & PAGE_MASK;
+ if (pmap != NULL)
+ paddr = pmap_extract(pmap, vaddr);
+ else
+ paddr = pmap_kextract(vaddr);
+ seglen = MIN(len, PAGE_SIZE - offset);
+ if (sg->sg_nseg == 0) {
+ ss = sg->sg_segs;
+ ss->ss_paddr = paddr;
+ ss->ss_len = seglen;
+ sg->sg_nseg = 1;
+ } else {
+ ss = &sg->sg_segs[sg->sg_nseg - 1];
+ error = _sglist_append_range(sg, &ss, paddr, seglen);
+ if (error)
+ return (error);
+ }
+ vaddr += seglen;
+ len -= seglen;
+ if (donep)
+ *donep += seglen;
+
+ while (len > 0) {
+ seglen = MIN(len, PAGE_SIZE);
+ if (pmap != NULL)
+ paddr = pmap_extract(pmap, vaddr);
+ else
+ paddr = pmap_kextract(vaddr);
+ error = _sglist_append_range(sg, &ss, paddr, seglen);
+ if (error)
+ return (error);
+ vaddr += seglen;
+ len -= seglen;
+ if (donep)
+ *donep += seglen;
+ }
+
+ return (0);
+}
+
+/*
+ * Determine the number of scatter/gather list elements needed to
+ * describe a kernel virtual address range.
+ */
+int
+sglist_count(void *buf, size_t len)
+{
+ vm_offset_t vaddr, vendaddr;
+ vm_paddr_t lastaddr, paddr;
+ int nsegs;
+
+ if (len == 0)
+ return (0);
+
+ vaddr = trunc_page((vm_offset_t)buf);
+ vendaddr = (vm_offset_t)buf + len;
+ nsegs = 1;
+ lastaddr = pmap_kextract(vaddr);
+ vaddr += PAGE_SIZE;
+ while (vaddr < vendaddr) {
+ paddr = pmap_kextract(vaddr);
+ if (lastaddr + PAGE_SIZE != paddr)
+ nsegs++;
+ lastaddr = paddr;
+ vaddr += PAGE_SIZE;
+ }
+ return (nsegs);
+}
+
+/*
+ * Allocate a scatter/gather list along with 'nsegs' segments. The
+ * 'mflags' parameters are the same as passed to malloc(9). The caller
+ * should use sglist_free() to free this list.
+ */
+struct sglist *
+sglist_alloc(int nsegs, int mflags)
+{
+ struct sglist *sg;
+
+ sg = kmalloc(sizeof(struct sglist) + nsegs * sizeof(struct sglist_seg),
+ M_SGLIST, mflags);
+ if (sg == NULL)
+ return (NULL);
+ sglist_init(sg, nsegs, (struct sglist_seg *)(sg + 1));
+ return (sg);
+}
+
+/*
+ * Free a scatter/gather list allocated via sglist_allc().
+ */
+void
+sglist_free(struct sglist *sg)
+{
+
+ if (refcount_release(&sg->sg_refs))
+ kfree(sg, M_SGLIST);
+}
+
+/*
+ * Append the segments to describe a single kernel virtual address
+ * range to a scatter/gather list. If there are insufficient
+ * segments, then this fails with EFBIG.
+ */
+int
+sglist_append(struct sglist *sg, void *buf, size_t len)
+{
+ struct sgsave save;
+ int error;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+ SGLIST_SAVE(sg, save);
+ error = _sglist_append_buf(sg, buf, len, NULL, NULL);
+ if (error)
+ SGLIST_RESTORE(sg, save);
+ return (error);
+}
+
+/*
+ * Append a single physical address range to a scatter/gather list.
+ * If there are insufficient segments, then this fails with EFBIG.
+ */
+int
+sglist_append_phys(struct sglist *sg, vm_paddr_t paddr, size_t len)
+{
+ struct sglist_seg *ss;
+ struct sgsave save;
+ int error;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+ if (len == 0)
+ return (0);
+
+ if (sg->sg_nseg == 0) {
+ sg->sg_segs[0].ss_paddr = paddr;
+ sg->sg_segs[0].ss_len = len;
+ sg->sg_nseg = 1;
+ return (0);
+ }
+ ss = &sg->sg_segs[sg->sg_nseg - 1];
+ SGLIST_SAVE(sg, save);
+ error = _sglist_append_range(sg, &ss, paddr, len);
+ if (error)
+ SGLIST_RESTORE(sg, save);
+ return (error);
+}
+
+/*
+ * Append the segments that describe a single mbuf chain to a
+ * scatter/gather list. If there are insufficient segments, then this
+ * fails with EFBIG.
+ */
+int
+sglist_append_mbuf(struct sglist *sg, struct mbuf *m0)
+{
+ struct sgsave save;
+ struct mbuf *m;
+ int error;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+
+ error = 0;
+ SGLIST_SAVE(sg, save);
+ for (m = m0; m != NULL; m = m->m_next) {
+ if (m->m_len > 0) {
+ error = sglist_append(sg, m->m_data, m->m_len);
+ if (error) {
+ SGLIST_RESTORE(sg, save);
+ return (error);
+ }
+ }
+ }
+ return (0);
+}
+
+/*
+ * Append the segments that describe a single user address range to a
+ * scatter/gather list. If there are insufficient segments, then this
+ * fails with EFBIG.
+ */
+int
+sglist_append_user(struct sglist *sg, void *buf, size_t len, struct thread *td)
+{
+ struct sgsave save;
+ int error;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+ SGLIST_SAVE(sg, save);
+ error = _sglist_append_buf(sg, buf, len,
+ vmspace_pmap(td->td_proc->p_vmspace), NULL);
+ if (error)
+ SGLIST_RESTORE(sg, save);
+ return (error);
+}
+
+/*
+ * Append the segments that describe a single uio to a scatter/gather
+ * list. If there are insufficient segments, then this fails with
+ * EFBIG.
+ */
+int
+sglist_append_uio(struct sglist *sg, struct uio *uio)
+{
+ struct iovec *iov;
+ struct sgsave save;
+ size_t resid, minlen;
+ pmap_t pmap;
+ int error, i;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+
+ resid = uio->uio_resid;
+ iov = uio->uio_iov;
+
+ if (uio->uio_segflg == UIO_USERSPACE) {
+ KASSERT(uio->uio_td != NULL,
+ ("sglist_append_uio: USERSPACE but no thread"));
+ pmap = vmspace_pmap(uio->uio_td->td_proc->p_vmspace);
+ } else
+ pmap = NULL;
+
+ error = 0;
+ SGLIST_SAVE(sg, save);
+ for (i = 0; i < uio->uio_iovcnt && resid != 0; i++) {
+ /*
+ * Now at the first iovec to load. Load each iovec
+ * until we have exhausted the residual count.
+ */
+ minlen = MIN(resid, iov[i].iov_len);
+ if (minlen > 0) {
+ error = _sglist_append_buf(sg, iov[i].iov_base, minlen,
+ pmap, NULL);
+ if (error) {
+ SGLIST_RESTORE(sg, save);
+ return (error);
+ }
+ resid -= minlen;
+ }
+ }
+ return (0);
+}
+
+/*
+ * Append the segments that describe at most 'resid' bytes from a
+ * single uio to a scatter/gather list. If there are insufficient
+ * segments, then only the amount that fits is appended.
+ */
+int
+sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid)
+{
+ struct iovec *iov;
+ size_t done;
+ pmap_t pmap;
+ int error, len;
+
+ if (sg->sg_maxseg == 0)
+ return (EINVAL);
+
+ if (uio->uio_segflg == UIO_USERSPACE) {
+ KASSERT(uio->uio_td != NULL,
+ ("sglist_consume_uio: USERSPACE but no thread"));
+ pmap = vmspace_pmap(uio->uio_td->td_proc->p_vmspace);
+ } else
+ pmap = NULL;
+
+ error = 0;
+ while (resid > 0 && uio->uio_resid) {
+ iov = uio->uio_iov;
+ len = iov->iov_len;
+ if (len == 0) {
+ uio->uio_iov++;
+ uio->uio_iovcnt--;
+ continue;
+ }
+ if (len > resid)
+ len = resid;
+
+ /*
+ * Try to append this iovec. If we run out of room,
+ * then break out of the loop.
+ */
+ error = _sglist_append_buf(sg, iov->iov_base, len, pmap, &done);
+ iov->iov_base = (char *)iov->iov_base + done;
+ iov->iov_len -= done;
+ uio->uio_resid -= done;
+ uio->uio_offset += done;
+ resid -= done;
+ if (error)
+ break;
+ }
+ return (0);
+}
+
+/*
+ * Allocate and populate a scatter/gather list to describe a single
+ * kernel virtual address range.
+ */
+struct sglist *
+sglist_build(void *buf, size_t len, int mflags)
+{
+ struct sglist *sg;
+ int nsegs;
+
+ if (len == 0)
+ return (NULL);
+
+ nsegs = sglist_count(buf, len);
+ sg = sglist_alloc(nsegs, mflags);
+ if (sg == NULL)
+ return (NULL);
+ if (sglist_append(sg, buf, len) != 0) {
+ sglist_free(sg);
+ return (NULL);
+ }
+ return (sg);
+}
+
+/*
+ * Clone a new copy of a scatter/gather list.
+ */
+struct sglist *
+sglist_clone(struct sglist *sg, int mflags)
+{
+ struct sglist *new;
+
+ if (sg == NULL)
+ return (NULL);
+ new = sglist_alloc(sg->sg_maxseg, mflags);
+ if (new == NULL)
+ return (NULL);
+ new->sg_nseg = sg->sg_nseg;
+ bcopy(sg->sg_segs, new->sg_segs, sizeof(struct sglist_seg) *
+ sg->sg_nseg);
+ return (new);
+}
+
+/*
+ * Calculate the total length of the segments described in a
+ * scatter/gather list.
+ */
+size_t
+sglist_length(struct sglist *sg)
+{
+ size_t space;
+ int i;
+
+ space = 0;
+ for (i = 0; i < sg->sg_nseg; i++)
+ space += sg->sg_segs[i].ss_len;
+ return (space);
+}
+
+/*
+ * Split a scatter/gather list into two lists. The scatter/gather
+ * entries for the first 'length' bytes of the 'original' list are
+ * stored in the '*head' list and are removed from 'original'.
+ *
+ * If '*head' is NULL, then a new list will be allocated using
+ * 'mflags'. If M_NOWAIT is specified and the allocation fails,
+ * ENOMEM will be returned.
+ *
+ * If '*head' is not NULL, it should point to an empty sglist. If it
+ * does not have enough room for the remaining space, then EFBIG will
+ * be returned. If '*head' is not empty, then EINVAL will be
+ * returned.
+ *
+ * If 'original' is shared (refcount > 1), then EDOOFUS will be
+ * returned.
+ */
+int
+sglist_split(struct sglist *original, struct sglist **head, size_t length,
+ int mflags)
+{
+ struct sglist *sg;
+ size_t space, split;
+ int count, i;
+
+ if (original->sg_refs > 1)
+ return (EDOOFUS);
+
+ /* Figure out how big of a sglist '*head' has to hold. */
+ count = 0;
+ space = 0;
+ split = 0;
+ for (i = 0; i < original->sg_nseg; i++) {
+ space += original->sg_segs[i].ss_len;
+ count++;
+ if (space >= length) {
+ /*
+ * If 'length' falls in the middle of a
+ * scatter/gather list entry, then 'split'
+ * holds how much of that entry will remain in
+ * 'original'.
+ */
+ split = space - length;
+ break;
+ }
+ }
+
+ /* Nothing to do, so leave head empty. */
+ if (count == 0)
+ return (0);
+
+ if (*head == NULL) {
+ sg = sglist_alloc(count, mflags);
+ if (sg == NULL)
+ return (ENOMEM);
+ *head = sg;
+ } else {
+ sg = *head;
+ if (sg->sg_maxseg < count)
+ return (EFBIG);
+ if (sg->sg_nseg != 0)
+ return (EINVAL);
+ }
+
+ /* Copy 'count' entries to 'sg' from 'original'. */
+ bcopy(original->sg_segs, sg->sg_segs, count *
+ sizeof(struct sglist_seg));
+ sg->sg_nseg = count;
+
+ /*
+ * If we had to split a list entry, fixup the last entry in
+ * 'sg' and the new first entry in 'original'. We also
+ * decrement 'count' by 1 since we will only be removing
+ * 'count - 1' segments from 'original' now.
+ */
+ if (split != 0) {
+ count--;
+ sg->sg_segs[count].ss_len -= split;
+ original->sg_segs[count].ss_paddr =
+ sg->sg_segs[count].ss_paddr + split;
+ original->sg_segs[count].ss_len = split;
+ }
+
+ /* Trim 'count' entries from the front of 'original'. */
+ original->sg_nseg -= count;
+ bcopy(original->sg_segs + count, original->sg_segs, count *
+ sizeof(struct sglist_seg));
+ return (0);
+}
+
+/*
+ * Append the scatter/gather list elements in 'second' to the
+ * scatter/gather list 'first'. If there is not enough space in
+ * 'first', EFBIG is returned.
+ */
+int
+sglist_join(struct sglist *first, struct sglist *second)
+{
+ struct sglist_seg *flast, *sfirst;
+ int append;
+
+ /* If 'second' is empty, there is nothing to do. */
+ if (second->sg_nseg == 0)
+ return (0);
+
+ /*
+ * If the first entry in 'second' can be appended to the last entry
+ * in 'first' then set append to '1'.
+ */
+ append = 0;
+ flast = &first->sg_segs[first->sg_nseg - 1];
+ sfirst = &second->sg_segs[0];
+ if (first->sg_nseg != 0 &&
+ flast->ss_paddr + flast->ss_len == sfirst->ss_paddr)
+ append = 1;
+
+ /* Make sure 'first' has enough room. */
+ if (first->sg_nseg + second->sg_nseg - append > first->sg_maxseg)
+ return (EFBIG);
+
+ /* Merge last in 'first' and first in 'second' if needed. */
+ if (append)
+ flast->ss_len += sfirst->ss_len;
+
+ /* Append new segments from 'second' to 'first'. */
+ bcopy(first->sg_segs + first->sg_nseg, second->sg_segs + append,
+ (second->sg_nseg - append) * sizeof(struct sglist_seg));
+ first->sg_nseg += second->sg_nseg - append;
+ sglist_reset(second);
+ return (0);
+}
+
+/*
+ * Generate a new scatter/gather list from a range of an existing
+ * scatter/gather list. The 'offset' and 'length' parameters specify
+ * the logical range of the 'original' list to extract. If that range
+ * is not a subset of the length of 'original', then EINVAL is
+ * returned. The new scatter/gather list is stored in '*slice'.
+ *
+ * If '*slice' is NULL, then a new list will be allocated using
+ * 'mflags'. If M_NOWAIT is specified and the allocation fails,
+ * ENOMEM will be returned.
+ *
+ * If '*slice' is not NULL, it should point to an empty sglist. If it
+ * does not have enough room for the remaining space, then EFBIG will
+ * be returned. If '*slice' is not empty, then EINVAL will be
+ * returned.
+ */
+int
+sglist_slice(struct sglist *original, struct sglist **slice, size_t offset,
+ size_t length, int mflags)
+{
+ struct sglist *sg;
+ size_t space, end, foffs, loffs;
+ int count, i, fseg;
+
+ /* Nothing to do. */
+ if (length == 0)
+ return (0);
+
+ /* Figure out how many segments '*slice' needs to have. */
+ end = offset + length;
+ space = 0;
+ count = 0;
+ fseg = 0;
+ foffs = loffs = 0;
+ for (i = 0; i < original->sg_nseg; i++) {
+ space += original->sg_segs[i].ss_len;
+ if (space > offset) {
+ /*
+ * When we hit the first segment, store its index
+ * in 'fseg' and the offset into the first segment
+ * of 'offset' in 'foffs'.
+ */
+ if (count == 0) {
+ fseg = i;
+ foffs = offset - (space -
+ original->sg_segs[i].ss_len);
+ //CTR1(KTR_DEV, "sglist_slice: foffs = %08lx", foffs);
+ }
+ count++;
+
+ /*
+ * When we hit the last segment, break out of
+ * the loop. Store the amount of extra space
+ * at the end of this segment in 'loffs'.
+ */
+ if (space >= end) {
+ loffs = space - end;
+ //CTR1(KTR_DEV, "sglist_slice: loffs = %08lx", loffs);
+ break;
+ }
+ }
+ }
+
+ /* If we never hit 'end', then 'length' ran off the end, so fail. */
+ if (space < end)
+ return (EINVAL);
+
+ if (*slice == NULL) {
+ sg = sglist_alloc(count, mflags);
+ if (sg == NULL)
+ return (ENOMEM);
+ *slice = sg;
+ } else {
+ sg = *slice;
+ if (sg->sg_maxseg < count)
+ return (EFBIG);
+ if (sg->sg_nseg != 0)
+ return (EINVAL);
+ }
+
+ /*
+ * Copy over 'count' segments from 'original' starting at
+ * 'fseg' to 'sg'.
+ */
+ bcopy(original->sg_segs + fseg, sg->sg_segs,
+ count * sizeof(struct sglist_seg));
+ sg->sg_nseg = count;
+
+ /* Fixup first and last segments if needed. */
+ if (foffs != 0) {
+ sg->sg_segs[0].ss_paddr += foffs;
+ sg->sg_segs[0].ss_len -= foffs;
+ //CTR2(KTR_DEV, "sglist_slice seg[0]: %08lx:%08lx",
+ // (long)sg->sg_segs[0].ss_paddr, sg->sg_segs[0].ss_len);
+ }
+ if (loffs != 0) {
+ sg->sg_segs[count - 1].ss_len -= loffs;
+ //CTR2(KTR_DEV, "sglist_slice seg[%d]: len %08x", count - 1,
+ // sg->sg_segs[count - 1].ss_len);
+ }
+ return (0);
+}
diff --git a/sys/sys/sglist.h b/sys/sys/sglist.h
new file mode 100644
index 0000000..95d6dfa
--- /dev/null
+++ b/sys/sys/sglist.h
@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 2008 Yahoo!, Inc.
+ * All rights reserved.
+ * Written by: John Baldwin <jhb at FreeBSD.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD: src/sys/sys/sglist.h,v 1.1.2.2.4.1 2010/06/14 02:09:06 kensmith Exp $
+ */
+
+/*
+ * A scatter/gather list describes a group of physical address ranges.
+ * Each physical address range consists of a starting address and a
+ * length.
+ */
+
+#ifndef __SGLIST_H__
+#define __SGLIST_H__
+
+#include <sys/refcount.h>
+
+struct sglist_seg {
+ vm_paddr_t ss_paddr;
+ size_t ss_len;
+};
+
+struct sglist {
+ struct sglist_seg *sg_segs;
+ int sg_refs;
+ u_short sg_nseg;
+ u_short sg_maxseg;
+};
+
+struct mbuf;
+struct uio;
+
+static __inline void
+sglist_init(struct sglist *sg, u_short maxsegs, struct sglist_seg *segs)
+{
+
+ sg->sg_segs = segs;
+ sg->sg_nseg = 0;
+ sg->sg_maxseg = maxsegs;
+ refcount_init(&sg->sg_refs, 1);
+}
+
+static __inline void
+sglist_reset(struct sglist *sg)
+{
+
+ sg->sg_nseg = 0;
+}
+
+static __inline struct sglist *
+sglist_hold(struct sglist *sg)
+{
+
+ refcount_acquire(&sg->sg_refs);
+ return (sg);
+}
+
+struct sglist *sglist_alloc(int nsegs, int mflags);
+int sglist_append(struct sglist *sg, void *buf, size_t len);
+int sglist_append_mbuf(struct sglist *sg, struct mbuf *m0);
+int sglist_append_phys(struct sglist *sg, vm_paddr_t paddr,
+ size_t len);
+int sglist_append_uio(struct sglist *sg, struct uio *uio);
+int sglist_append_user(struct sglist *sg, void *buf, size_t len,
+ struct thread *td);
+struct sglist *sglist_build(void *buf, size_t len, int mflags);
+struct sglist *sglist_clone(struct sglist *sg, int mflags);
+int sglist_consume_uio(struct sglist *sg, struct uio *uio, size_t resid);
+int sglist_count(void *buf, size_t len);
+void sglist_free(struct sglist *sg);
+int sglist_join(struct sglist *first, struct sglist *second);
+size_t sglist_length(struct sglist *sg);
+int sglist_slice(struct sglist *original, struct sglist **slice,
+ size_t offset, size_t length, int mflags);
+int sglist_split(struct sglist *original, struct sglist **head,
+ size_t length, int mflags);
+
+#endif /* !__SGLIST_H__ */
--
1.7.0.4
--Boundary_(ID_UFDgo8KnsWSexNpyQBJ7hg)--
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