Commit 8beb3300 authored Jun 13, 2016 by James Bottomley Committed by Martin K. Petersen Jun 14, 2016

53c700: fix BUG on untagged commands



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: 64d513ac - "scsi: use host wide tags by default"
Cc: stable@vger.kernel.org	# 4.4+
Reported-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: James Bottomley <jejb@linux.vnet.ibm.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent 72d8c36e

drivers/scsi/53c700.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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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