target: Fix max_unmap_lba_count calc overflow
max_discard_sectors only 32bits, and some non scsi backend
devices will set this to the max 0xffffffff, so we can end up
overflowing during the max_unmap_lba_count calculation.
This fixes a regression caused by my patch:
commit 8a9ebe717a133ba7bc90b06047f43cc6b8bcb8b3
Author: Mike Christie <mchristi@redhat.com>
Date: Mon Jan 18 14:09:27 2016 -0600
target: Fix WRITE_SAME/DISCARD conversion to linux 512b sectors
which can result in extra discards being sent to due the overflow
causing max_unmap_lba_count to be smaller than what the backing
device can actually support.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index a4046ca..6b42348 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -821,13 +821,15 @@
* in ATA and we need to set TPE=1
*/
bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
- struct request_queue *q, int block_size)
+ struct request_queue *q)
{
+ int block_size = queue_logical_block_size(q);
+
if (!blk_queue_discard(q))
return false;
- attrib->max_unmap_lba_count = (q->limits.max_discard_sectors << 9) /
- block_size;
+ attrib->max_unmap_lba_count =
+ q->limits.max_discard_sectors >> (ilog2(block_size) - 9);
/*
* Currently hardcoded to 1 in Linux/SCSI code..
*/