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authorChristoph Hellwig <hch@lst.de>2015-08-07 18:15:11 +0200
committerJens Axboe <axboe@fb.com>2015-08-17 08:12:51 -0600
commit10c95ed9aa2970e05fedb4ac8b3ce1b934dab17b (patch)
tree1d95c738627ea9d01c90e831a5676766458444c0
parent0048b4837affd153897ed1222283492070027aa9 (diff)
downloadlinux-10c95ed9aa2970e05fedb4ac8b3ce1b934dab17b.tar.gz
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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--include/linux/scatterlist.h4
-rw-r--r--lib/scatterlist.c4
2 files changed, 0 insertions, 8 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 9b1ef0c820a7..698e906ca730 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -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,
 			    struct scatterlist *sgl)
 {
-#ifndef CONFIG_ARCH_HAS_SG_CHAIN
-	BUG();
-#endif
-
 	/*
 	 * offset and length are unused for chain entry.  Clear them.
 	 */
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index d105a9f56878..bafa9933fa76 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -105,16 +105,12 @@ EXPORT_SYMBOL(sg_nents_for_len);
  **/
 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;
 	unsigned int i;
 
 	for_each_sg(sgl, sg, nents, i)
 		ret = sg;
 
-#endif
 #ifdef CONFIG_DEBUG_SG
 	BUG_ON(sgl[0].sg_magic != SG_MAGIC);
 	BUG_ON(!sg_is_last(ret));