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Commit 2a1bf8f9 authored by Dave Gordon's avatar Dave Gordon Committed by Linus Torvalds
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lib/scatterlist: mark input buffer parameters as 'const' 



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: default avatarDave Gordon <david.s.gordon@intel.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4dc7daf8

include/linux/scatterlist.h

+2 −2
Original line number Diff line number Diff line
@@ -266,12 +266,12 @@ 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);

lib/scatterlist.c

+4 −4
Original line number Diff line number Diff line
@@ -701,9 +701,9 @@ 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);
@@ -736,9 +736,9 @@ 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);