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lib/scatterlist: Add SG_MITER_LOCAL and use it

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Add kmap_local support to the scatterlist iterator.  Use it for
all the helper functions in lib/scatterlist.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Herbert Xu 2025-03-13 13:14:53 +08:00
parent f3bda3b9b6
commit fc8d5bba61
2 changed files with 9 additions and 4 deletions
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1
include/linux/scatterlist.h
View File

@ -671,6 +671,7 @@ sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter)
#define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */
#define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */
#define SG_MITER_FROM_SG (1 << 2) /* nop */
#define SG_MITER_LOCAL (1 << 3) /* use kmap_local */
struct sg_mapping_iter {
/* the following three fields can be accessed directly */

12
lib/scatterlist.c
View File

@ -879,7 +879,7 @@ EXPORT_SYMBOL(sg_miter_skip);
* @miter->addr and @miter->length point to the current mapping.
*
* Context:
* May sleep if !SG_MITER_ATOMIC.
* May sleep if !SG_MITER_ATOMIC && !SG_MITER_LOCAL.
*
* Returns:
* true if @miter contains the next mapping. false if end of sg
@ -901,6 +901,8 @@ bool sg_miter_next(struct sg_mapping_iter *miter)
if (miter->__flags & SG_MITER_ATOMIC)
miter->addr = kmap_atomic(miter->page) + miter->__offset;
else if (miter->__flags & SG_MITER_LOCAL)
miter->addr = kmap_local_page(miter->page) + miter->__offset;
else
miter->addr = kmap(miter->page) + miter->__offset;
@ -936,7 +938,9 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
if (miter->__flags & SG_MITER_ATOMIC) {
WARN_ON_ONCE(!pagefault_disabled());
kunmap_atomic(miter->addr);
} else
} else if (miter->__flags & SG_MITER_LOCAL)
kunmap_local(miter->addr);
else
kunmap(miter->page);
miter->page = NULL;
@ -965,7 +969,7 @@ size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
{
unsigned int offset = 0;
struct sg_mapping_iter miter;
unsigned int sg_flags = SG_MITER_ATOMIC;
unsigned int sg_flags = SG_MITER_LOCAL;
if (to_buffer)
sg_flags |= SG_MITER_FROM_SG;
@ -1080,7 +1084,7 @@ size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
{
unsigned int offset = 0;
struct sg_mapping_iter miter;
unsigned int sg_flags = SG_MITER_ATOMIC | SG_MITER_TO_SG;
unsigned int sg_flags = SG_MITER_LOCAL | SG_MITER_TO_SG;
sg_miter_start(&miter, sgl, nents, sg_flags);