scsi: core: Also call destroy_rcu_head() for passthrough requests

bvanassche · martinkpetersen · commit db983f6eef57 · 2019-03-19T14:13:08.000-04:00
cmd-&gt;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 &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.com&gt;
Cc: Ewan D. Milne &lt;emilne@redhat.com&gt;
Cc: Johannes Thumshirn &lt;jthumshirn@suse.de&gt;
Reported-by: Ewan D. Milne &lt;emilne@redhat.com&gt;
Signed-off-by: Bart Van Assche &lt;bvanassche@acm.org&gt;
Reviewed-by: Hannes Reinecke &lt;hare@suse.com&gt;
Signed-off-by: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
@@ -585,9 +585,16 @@ 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.
