scsi: fix memory leak with scsi-mq
Fix a memory leak with scsi-mq triggered by commands with large data
transfer length.
__sg_alloc_table() sets both table->nents and table->orig_nents to the
same value. When the scatterlist is DMA-mapped, table->nents is
overwritten with the (possibly smaller) size of the DMA-mapped
scatterlist, while table->orig_nents retains the original size of the
allocated scatterlist. scsi_free_sgtable() should therefore check
orig_nents instead of nents, and all code that initializes sdb->table
without calling __sg_alloc_table() should set both nents and orig_nents.
Fixes: d285203cf647 ("scsi: add support for a blk-mq based I/O path.")
Cc: <stable@vger.kernel.org> # 3.17+
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b1a2631..448ebda 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -583,7 +583,7 @@
static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
{
- if (mq && sdb->table.nents <= SCSI_MAX_SG_SEGMENTS)
+ if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
return;
__sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
}
@@ -597,8 +597,8 @@
if (mq) {
if (nents <= SCSI_MAX_SG_SEGMENTS) {
- sdb->table.nents = nents;
- sg_init_table(sdb->table.sgl, sdb->table.nents);
+ sdb->table.nents = sdb->table.orig_nents = nents;
+ sg_init_table(sdb->table.sgl, nents);
return 0;
}
first_chunk = sdb->table.sgl;