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Commit 10c95ed9 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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scatterlist: allow limited chaining without ARCH_HAS_SG_CHAIN 



There are a couple of uses of struct scatterlist that never go to
the dma_map_sg() helper and thus don't care about ARCH_HAS_SG_CHAIN
which indicates that we can map chained S/G list.

The most important one is the crypto code, which currently has
to open code a few helpers to always allow chaining.  This patch
removes a few #ifdef ARCH_HAS_SG_CHAIN statements so that we can
switch the crypto code to these common helpers.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 0048b483

include/linux/scatterlist.h

+0 −4
Original line number Original line Diff line number Diff line
@@ -161,10 +161,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, 
static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,

static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,

			    struct scatterlist *sgl)

			    struct scatterlist *sgl)

{

{

#ifndef CONFIG_ARCH_HAS_SG_CHAIN

	BUG();

#endif



	/*

	/*

	 * offset and length are unused for chain entry.  Clear them.

	 * offset and length are unused for chain entry.  Clear them.

	 */

	 */

lib/scatterlist.c

+0 −4
Original line number Original line Diff line number Diff line
@@ -105,16 +105,12 @@ EXPORT_SYMBOL(sg_nents_for_len); 
 **/

 **/

struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents)

struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents)

{

{

#ifndef CONFIG_ARCH_HAS_SG_CHAIN

	struct scatterlist *ret = &sgl[nents - 1];

#else

	struct scatterlist *sg, *ret = NULL;

	struct scatterlist *sg, *ret = NULL;

	unsigned int i;

	unsigned int i;





	for_each_sg(sgl, sg, nents, i)

	for_each_sg(sgl, sg, nents, i)

		ret = sg;

		ret = sg;





#endif

#ifdef CONFIG_DEBUG_SG

#ifdef CONFIG_DEBUG_SG

	BUG_ON(sgl[0].sg_magic != SG_MAGIC);

	BUG_ON(sgl[0].sg_magic != SG_MAGIC);

	BUG_ON(!sg_is_last(ret));

	BUG_ON(!sg_is_last(ret));