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authorMing Lei <ming.lei@redhat.com>2019-06-06 10:34:08 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2019-06-20 21:21:33 +0200
commitb79d9a09ae23c7047bdce3a15e284398334198ea (patch)
treeb2cdeab4564fdd2bc3706eb1aa0864e3e4ec1e6f /lib/sg_pool.c
parentscsi: core: avoid preallocating big SGL for data (diff)
downloadlinux-b79d9a09ae23c7047bdce3a15e284398334198ea.tar.xz
linux-b79d9a09ae23c7047bdce3a15e284398334198ea.zip
scsi: lib/sg_pool.c: clear 'first_chunk' in case of no preallocation
If user doesn't ask to preallocate by passing zero 'nents_first_chunk' to sg_alloc_table_chained, we need to make sure that 'first_chunk' is cleared. Otherwise, __sg_alloc_table() still may think that the 1st SGL should be from the preallocation. Fixes the issue by clearing 'first_chunk' in sg_alloc_table_chained() if 'nents_first_chunk' is zero. Cc: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Ewan D. Milne <emilne@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Guenter Roeck <linux@roeck-us.net> Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'lib/sg_pool.c')
-rw-r--r--lib/sg_pool.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/lib/sg_pool.c b/lib/sg_pool.c
index b3b8cf62ff49..f1cc8372df67 100644
--- a/lib/sg_pool.c
+++ b/lib/sg_pool.c
@@ -102,7 +102,9 @@ EXPORT_SYMBOL_GPL(sg_free_table_chained);
*
* Description:
* Allocate and chain SGLs in an sg table. If @nents@ is larger than
- * @nents_first_chunk 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,
@@ -121,7 +123,7 @@ int sg_alloc_table_chained(struct sg_table *table, int nents,
}
/* User supposes that the 1st SGL includes real entry */
- if (nents_first_chunk == 1) {
+ if (nents_first_chunk <= 1) {
first_chunk = NULL;
nents_first_chunk = 0;
}