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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 15:17:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 15:17:41 -0700
commit1f7563f743d7081710a9d186a8b203997d09f383 (patch)
tree55091227fb177f25c45f33dfb5f0b2a5e22ccfa7 /lib/sg_pool.c
parentba6d10ab8014ac10d25ca513352b6665e73b5785 (diff)
parent3e99b3b13a1fc8f7354edaee4c04f73a07faba69 (diff)
downloadlinux-1f7563f743d7081710a9d186a8b203997d09f383.tar.bz2
Merge tag 'scsi-sg' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI scatter-gather list updates from James Bottomley: "This topic branch covers a fundamental change in how our sg lists are allocated to make mq more efficient by reducing the size of the preallocated sg list. This necessitates a large number of driver changes because the previous guarantee that if a driver specified SG_ALL as the size of its scatter list, it would get a non-chained list and didn't need to bother with scatterlist iterators is now broken and every driver *must* use scatterlist iterators. This was broken out as a separate topic because we need to convert all the drivers before pulling the trigger and unconverted drivers kept being found, necessitating a rebase" * tag 'scsi-sg' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (21 commits) scsi: core: don't preallocate small SGL in case of NO_SG_CHAIN scsi: lib/sg_pool.c: clear 'first_chunk' in case of no preallocation scsi: core: avoid preallocating big SGL for data scsi: core: avoid preallocating big SGL for protection information scsi: lib/sg_pool.c: improve APIs for allocating sg pool scsi: esp: use sg helper to iterate over scatterlist scsi: NCR5380: use sg helper to iterate over scatterlist scsi: wd33c93: use sg helper to iterate over scatterlist scsi: ppa: use sg helper to iterate over scatterlist scsi: pcmcia: nsp_cs: use sg helper to iterate over scatterlist scsi: imm: use sg helper to iterate over scatterlist scsi: aha152x: use sg helper to iterate over scatterlist scsi: s390: zfcp_fc: use sg helper to iterate over scatterlist scsi: staging: unisys: visorhba: use sg helper to iterate over scatterlist scsi: usb: image: microtek: use sg helper to iterate over scatterlist scsi: pmcraid: use sg helper to iterate over scatterlist scsi: ipr: use sg helper to iterate over scatterlist scsi: mvumi: use sg helper to iterate over scatterlist scsi: lpfc: use sg helper to iterate over scatterlist scsi: advansys: use sg helper to iterate over scatterlist ...
Diffstat (limited to 'lib/sg_pool.c')
-rw-r--r--lib/sg_pool.c39
1 files changed, 29 insertions, 10 deletions
diff --git a/lib/sg_pool.c b/lib/sg_pool.c
index cff20df2695e..db29e5c1f790 100644
--- a/lib/sg_pool.c
+++ b/lib/sg_pool.c
@@ -70,18 +70,27 @@ static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
/**
* sg_free_table_chained - Free a previously mapped sg table
* @table: The sg table header to use
- * @first_chunk: was first_chunk not NULL in sg_alloc_table_chained?
+ * @nents_first_chunk: size of the first_chunk SGL passed to
+ * sg_alloc_table_chained
*
* Description:
* Free an sg table previously allocated and setup with
* sg_alloc_table_chained().
*
+ * @nents_first_chunk has to be same with that same parameter passed
+ * to sg_alloc_table_chained().
+ *
**/
-void sg_free_table_chained(struct sg_table *table, bool first_chunk)
+void sg_free_table_chained(struct sg_table *table,
+ unsigned nents_first_chunk)
{
- if (first_chunk && table->orig_nents <= SG_CHUNK_SIZE)
+ if (table->orig_nents <= nents_first_chunk)
return;
- __sg_free_table(table, SG_CHUNK_SIZE, first_chunk, sg_pool_free);
+
+ if (nents_first_chunk == 1)
+ nents_first_chunk = 0;
+
+ __sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free);
}
EXPORT_SYMBOL_GPL(sg_free_table_chained);
@@ -90,31 +99,41 @@ EXPORT_SYMBOL_GPL(sg_free_table_chained);
* @table: The sg table header to use
* @nents: Number of entries in sg list
* @first_chunk: first SGL
+ * @nents_first_chunk: number of the SGL of @first_chunk
*
* Description:
* Allocate and chain SGLs in an sg table. If @nents@ is larger than
- * SG_CHUNK_SIZE a chained sg table will be setup.
+ * @nents_first_chunk a chained sg table will be setup. @first_chunk is
+ * ignored if nents_first_chunk <= 1 because user expects the SGL points
+ * non-chain SGL.
*
**/
int sg_alloc_table_chained(struct sg_table *table, int nents,
- struct scatterlist *first_chunk)
+ struct scatterlist *first_chunk, unsigned nents_first_chunk)
{
int ret;
BUG_ON(!nents);
- if (first_chunk) {
- if (nents <= SG_CHUNK_SIZE) {
+ if (first_chunk && nents_first_chunk) {
+ if (nents <= nents_first_chunk) {
table->nents = table->orig_nents = nents;
sg_init_table(table->sgl, nents);
return 0;
}
}
+ /* User supposes that the 1st SGL includes real entry */
+ if (nents_first_chunk <= 1) {
+ first_chunk = NULL;
+ nents_first_chunk = 0;
+ }
+
ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
- first_chunk, GFP_ATOMIC, sg_pool_alloc);
+ first_chunk, nents_first_chunk,
+ GFP_ATOMIC, sg_pool_alloc);
if (unlikely(ret))
- sg_free_table_chained(table, (bool)first_chunk);
+ sg_free_table_chained(table, nents_first_chunk);
return ret;
}
EXPORT_SYMBOL_GPL(sg_alloc_table_chained);