SCSI: Fix error handling when no ULD is attached

Commit 18a4d0a ("[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 <[email protected]> Reported-by: Bart Van Assche <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
askender · Apr 15, 2012 · 919f797 · 919f797
1 parent bfecc60
commit 919f797
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 1 deletion.
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
@@ -835,7 +835,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
 
 	scsi_eh_restore_cmnd(scmd, &ses);
 
-	if (sdrv->eh_action)
+	if (sdrv && sdrv->eh_action)
 		rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
 
 	return rtn;

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
@@ -134,6 +134,9 @@ struct scsi_cmnd {
 
 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;
 }