SCSI: Fix error handling when no ULD is attached
Commit 18a4d0a22ed6 ("[SCSI] Handle disk devices which can not process
medium access commands") introduced a bug in which we would attempt to
dereference the scsi driver even when the device had no ULD attached.
Ensure that a driver is registered and make the driver accessor function
more resilient to errors during device discovery.
Reported-by: Elric Fu <elricfu1@gmail.com>
Reported-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 377df4a..1e11985 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -134,6 +134,9 @@
static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
+ if (!cmd->request->rq_disk)
+ return NULL;
+
return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
}