4.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: James Bottomley <[email protected]> commit 8beb330044d0d1878c7b92290e91c0b889e92633 upstream. 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" Reported-by: Helge Deller <[email protected]> Tested-by: Helge Deller <[email protected]> Signed-off-by: James Bottomley <[email protected]> Reviewed-by: Johannes Thumshirn <[email protected]> Reviewed-by: Ewan D. Milne <[email protected]> Acked-by: Christoph Hellwig <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/scsi/53c700.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/scsi/53c700.c +++ b/drivers/scsi/53c700.c @@ -1122,7 +1122,7 @@ process_script_interrupt(__u32 dsps, __u } 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_cmn 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
