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authorChristoph Hellwig <hch@lst.de>2014-04-15 14:38:31 +0200
committerChristoph Hellwig <hch@lst.de>2014-07-25 17:16:21 -0400
commitc53c6d6a68b13b1dff2892551b56cfdc07887d9e (patch)
tree8bd6ddc1ff0f33e357ad6c230f62fd7b1cf1b28a /include/linux/scatterlist.h
parentf6d47e74fcb2814225e429c94355ad1c551daffb (diff)
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scatterlist: allow chaining to preallocated chunks
Blk-mq drivers usually preallocate their S/G list as part of the request, but if we want to support the very large S/G lists currently supported by the SCSI code that would tie up a lot of memory in the preallocated request pool. Add support to the scatterlist code so that it can initialize a S/G list that uses a preallocated first chunks and dynamically allocated additional chunks. That way the scsi-mq code can preallocate a first page worth of S/G entries as part of the request, and dynamically extend the S/G list when needed. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
Diffstat (limited to 'include/linux/scatterlist.h')
-rw-r--r--include/linux/scatterlist.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index a964f7285600..f4ec8bbcb372 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -229,10 +229,10 @@ void sg_init_one(struct scatterlist *, const void *, unsigned int);
typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
-void __sg_free_table(struct sg_table *, unsigned int, sg_free_fn *);
+void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *);
void sg_free_table(struct sg_table *);
-int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t,
- sg_alloc_fn *);
+int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
+ struct scatterlist *, gfp_t, sg_alloc_fn *);
int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
int sg_alloc_table_from_pages(struct sg_table *sgt,
struct page **pages, unsigned int n_pages,
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