[ Upstream commit db983f6eef57a9d78af79bc32389b7e60eb3c47d ]

cmd->rcu is initialized by scsi_initialize_rq(). For passthrough
requests, blk_get_request() calls scsi_initialize_rq(). For filesystem
requests, scsi_init_command() calls scsi_initialize_rq(). Make sure
that destroy_rcu_head() is called for passthrough requests.

Cc: Christoph Hellwig <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Ewan D. Milne <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Reported-by: Ewan D. Milne <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 drivers/scsi/scsi_lib.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 5a6e8e12701a..655ad26106e4 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -598,9 +598,16 @@ static bool scsi_end_request(struct request *req, 
blk_status_t error,
        if (!blk_rq_is_scsi(req)) {
                WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
                cmd->flags &= ~SCMD_INITIALIZED;
-               destroy_rcu_head(&cmd->rcu);
        }
 
+       /*
+        * Calling rcu_barrier() is not necessary here because the
+        * SCSI error handler guarantees that the function called by
+        * call_rcu() has been called before scsi_end_request() is
+        * called.
+        */
+       destroy_rcu_head(&cmd->rcu);
+
        /*
         * In the MQ case the command gets freed by __blk_mq_end_request,
         * so we have to do all cleanup that depends on it earlier.
-- 
2.19.1



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