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Subject[PATCH] lib/scatterlist: mark input buffer parameters as 'const'
Date
The 'buf' parameter of sg(p)copy_from_buffer() can and should be
const-qualified, although because of the shared implementation of
_to_buffer() and _from_buffer(), we have to cast this away internally.

This means that callers who have a 'const' buffer containing the data
to be copied to the sg-list no longer have to cast away the const-ness
themselves. It also enables improved coverage by code analysis tools.

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
---
include/linux/scatterlist.h | 4 ++--
lib/scatterlist.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index ed8f9e7..c90038b 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -240,12 +240,12 @@ int sg_alloc_table_from_pages(struct sg_table *sgt,
gfp_t gfp_mask);

size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
- void *buf, size_t buflen);
+ const void *buf, size_t buflen);
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);
+ const 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);

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index c9f2e8c..9df76c4 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -669,9 +669,9 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
*
**/
size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
- void *buf, size_t buflen)
+ const void *buf, size_t buflen)
{
- return sg_copy_buffer(sgl, nents, buf, buflen, 0, false);
+ return sg_copy_buffer(sgl, nents, (void *)buf, buflen, 0, false);
}
EXPORT_SYMBOL(sg_copy_from_buffer);

@@ -704,9 +704,9 @@ EXPORT_SYMBOL(sg_copy_to_buffer);
*
**/
size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents,
- void *buf, size_t buflen, off_t skip)
+ const void *buf, size_t buflen, off_t skip)
{
- return sg_copy_buffer(sgl, nents, buf, buflen, skip, false);
+ return sg_copy_buffer(sgl, nents, (void *)buf, buflen, skip, false);
}
EXPORT_SYMBOL(sg_pcopy_from_buffer);

--
1.7.9.5


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