Subject: + lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer.patch added to -mm tree
To: akinobu.mita@xxxxxxxxx,JBottomley@xxxxxxxxxxxxx,davem@xxxxxxxxxxxxx,dgilbert@xxxxxxxxxxxx,herbert@xxxxxxxxxxxxxxxxxxx,horia.geanta@xxxxxxxxxxxxx,imre.deak@xxxxxxxxx,tj@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 25 Jun 2013 13:52:48 -0700
The patch titled
Subject: lib/scatterlist: introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer()
has been added to the -mm tree. Its filename is
lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer.patch
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From: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Subject: lib/scatterlist: introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer()
The only difference between sg_pcopy_{from,to}_buffer() and
sg_copy_{from,to}_buffer() is an additional argument that specifies the
number of bytes to skip the SG list before copying.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: "James E.J. Bottomley" <JBottomley@xxxxxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Horia Geanta <horia.geanta@xxxxxxxxxxxxx>
Cc: Imre Deak <imre.deak@xxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/scatterlist.h | 5 +
lib/scatterlist.c | 88 ++++++++++++++++++++++++++++++++--
2 files changed, 88 insertions(+), 5 deletions(-)
diff -puN include/linux/scatterlist.h~lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer include/linux/scatterlist.h
--- a/include/linux/scatterlist.h~lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer
+++ a/include/linux/scatterlist.h
@@ -244,6 +244,11 @@ size_t sg_copy_from_buffer(struct scatte
size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
void *buf, size_t buflen);
+size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen, off_t skip);
+size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen, off_t skip);
+
/*
* Maximum number of entries that will be allocated in one piece, if
* a list larger than this is required then chaining will be utilized.
diff -puN lib/scatterlist.c~lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer lib/scatterlist.c
--- a/lib/scatterlist.c~lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer
+++ a/lib/scatterlist.c
@@ -476,6 +476,43 @@ static bool sg_miter_get_next_page(struc
}
/**
+ * sg_miter_skip - reposition mapping iterator
+ * @miter: sg mapping iter to be skipped
+ * @offset: number of bytes to plus the current location
+ *
+ * Description:
+ * Sets the offset of @miter to its current location plus @offset bytes.
+ * If mapping iterator @miter has been proceeded by sg_miter_next(), this
+ * stops @miter.
+ *
+ * Context:
+ * Don't care if @miter is stopped, or not proceeded yet.
+ * Otherwise, preemption disabled if the SG_MITER_ATOMIC is set.
+ *
+ * Returns:
+ * true if @miter contains the valid mapping. false if end of sg
+ * list is reached.
+ */
+static bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)
+{
+ sg_miter_stop(miter);
+
+ while (offset) {
+ off_t consumed;
+
+ if (!sg_miter_get_next_page(miter))
+ return false;
+
+ consumed = min_t(off_t, offset, miter->__remaining);
+ miter->__offset += consumed;
+ miter->__remaining -= consumed;
+ offset -= consumed;
+ }
+
+ return true;
+}
+
+/**
* sg_miter_next - proceed mapping iterator to the next mapping
* @miter: sg mapping iter to proceed
*
@@ -561,14 +598,16 @@ EXPORT_SYMBOL(sg_miter_stop);
* @nents: Number of SG entries
* @buf: Where to copy from
* @buflen: The number of bytes to copy
- * @to_buffer: transfer direction (non zero == from an sg list to a
- * buffer, 0 == from a buffer to an sg list
+ * @skip: Number of bytes to skip before copying
+ * @to_buffer: transfer direction (true == from an sg list to a
+ * buffer, false == from a buffer to an sg list
*
* Returns the number of copied bytes.
*
**/
static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
- void *buf, size_t buflen, int to_buffer)
+ void *buf, size_t buflen, off_t skip,
+ bool to_buffer)
{
unsigned int offset = 0;
struct sg_mapping_iter miter;
@@ -582,6 +621,9 @@ static size_t sg_copy_buffer(struct scat
sg_miter_start(&miter, sgl, nents, sg_flags);
+ if (!sg_miter_skip(&miter, skip))
+ return false;
+
local_irq_save(flags);
while (sg_miter_next(&miter) && offset < buflen) {
@@ -616,7 +658,7 @@ static size_t sg_copy_buffer(struct scat
size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
void *buf, size_t buflen)
{
- return sg_copy_buffer(sgl, nents, buf, buflen, 0);
+ return sg_copy_buffer(sgl, nents, buf, buflen, 0, false);
}
EXPORT_SYMBOL(sg_copy_from_buffer);
@@ -633,6 +675,42 @@ EXPORT_SYMBOL(sg_copy_from_buffer);
size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
void *buf, size_t buflen)
{
- return sg_copy_buffer(sgl, nents, buf, buflen, 1);
+ return sg_copy_buffer(sgl, nents, buf, buflen, 0, true);
}
EXPORT_SYMBOL(sg_copy_to_buffer);
+
+/**
+ * sg_pcopy_from_buffer - Copy from a linear buffer to an SG list
+ * @sgl: The SG list
+ * @nents: Number of SG entries
+ * @buf: Where to copy from
+ * @skip: Number of bytes to skip before copying
+ * @buflen: The number of bytes to copy
+ *
+ * Returns the number of copied bytes.
+ *
+ **/
+size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen, off_t skip)
+{
+ return sg_copy_buffer(sgl, nents, buf, buflen, skip, false);
+}
+EXPORT_SYMBOL(sg_pcopy_from_buffer);
+
+/**
+ * sg_pcopy_to_buffer - Copy from an SG list to a linear buffer
+ * @sgl: The SG list
+ * @nents: Number of SG entries
+ * @buf: Where to copy to
+ * @skip: Number of bytes to skip before copying
+ * @buflen: The number of bytes to copy
+ *
+ * Returns the number of copied bytes.
+ *
+ **/
+size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+ void *buf, size_t buflen, off_t skip)
+{
+ return sg_copy_buffer(sgl, nents, buf, buflen, skip, true);
+}
+EXPORT_SYMBOL(sg_pcopy_to_buffer);
_
Patches currently in -mm which might be from akinobu.mita@xxxxxxxxx are
linux-next.patch
lib-scatterlist-factor-out-sg_miter_get_next_page-from-sg_miter_next.patch
lib-scatterlist-introduce-sg_pcopy_from_buffer-and-sg_pcopy_to_buffer.patch
crypto-talitos-use-sg_pcopy_to_buffer.patch
scsi_debug-fix-do_device_access-with-wrap-around-range.patch
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