The untagged command case in the 53c700 driver has been broken since
host wide tags were enabled because the replaced scsi_find_tag()
function had a special case for the tag value SCSI_NO_TAG to retrieve
sdev->current_cmnd. The replacement function scsi_host_find_tag() has
no such special case and returns NULL causing untagged commands to
trigger a BUG() in the driver. Inspection shows that the 53c700 is the
only driver using this SCSI_NO_TAG case, so a local fix in the driver
suffices to fix this problem globally.
Fixes: 64d513ac31b - "scsi: use host wide tags by default"
Cc: stable@xxxxxxxxxxxxxxx # 4.4+
Reported-by: Helge Deller <deller@xxxxxx>
Tested-by: Helge Deller <deller@xxxxxx>
Signed-off-by: James Bottomley <jejb@xxxxxxxxxxxxxxxxxx>
---
diff --git a/drivers/scsi/53c700.c b/drivers/scsi/53c700.c
index d4c2856..3ddc85e 100644
--- a/drivers/scsi/53c700.c
+++ b/drivers/scsi/53c700.c
@@ -1122,7 +1122,7 @@ process_script_interrupt(__u32 dsps, __u32 dsp, struct scsi_cmnd *SCp,
} else {
struct scsi_cmnd *SCp;
- SCp = scsi_host_find_tag(SDp->host, SCSI_NO_TAG);
+ SCp = SDp->current_cmnd;
if(unlikely(SCp == NULL)) {
sdev_printk(KERN_ERR, SDp,
"no saved request for untagged cmd\n");
@@ -1826,7 +1826,7 @@ NCR_700_queuecommand_lck(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *)
slot->tag, slot);
} else {
slot->tag = SCSI_NO_TAG;
- /* must populate current_cmnd for scsi_host_find_tag to work */
+ /* save current command for reselection */
SCp->device->current_cmnd = SCp;
}
/* sanity check: some of the commands generated by the mid-layer
--
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