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Commit 24c14200 authored Aug 07, 2012 by Lalit Chandivade Committed by James Bottomley Sep 14, 2012

[SCSI] qla4xxx: Properly handle SCSI underrun while processing status IOCBs.



The current code would incorrectly return a DID_OK for a
CHECK CONDITION with Recovered error sense key causing incorrect
completion of a command when there is a dropped frame.

Signed-off-by: Lalit Chandivade <lalit.chandivade@qlogic.com>
Signed-off-by: Tej Parkash <tej.parkash@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

parent 80c53e64

drivers/scsi/qla4xxx/ql4_isr.c

+59 −43

Original line number	Diff line number	Diff line
		@@ -243,56 +243,72 @@ static void qla4xxx_status_entry(struct scsi_qla_host *ha,

		scsi_set_resid(cmd, residual);

		/*
		* If there is scsi_status, it takes precedense over
		* underflow condition.
		if (sts_entry->iscsiFlags & ISCSI_FLAG_RESIDUAL_UNDER) {

		/* Both the firmware and target reported UNDERRUN:
		*
		* MID-LAYER UNDERFLOW case:
		* Some kernels do not properly detect midlayer
		* underflow, so we manually check it and return
		* ERROR if the minimum required data was not
		* received.
		*
		* ALL OTHER cases:
		* Fall thru to check scsi_status
		*/
		if (scsi_status != 0) {
		cmd->result = DID_OK << 16 \| scsi_status;
		if (!scsi_status && (scsi_bufflen(cmd) - residual) <
		cmd->underflow) {
		DEBUG2(ql4_printk(KERN_INFO, ha,
		"scsi%ld:%d:%d:%d: %s: Mid-layer Data underrun, xferlen = 0x%x,residual = 0x%x\n",
		ha->host_no,
		cmd->device->channel,
		cmd->device->id,
		cmd->device->lun, __func__,
		scsi_bufflen(cmd),
		residual));

		if (scsi_status != SCSI_CHECK_CONDITION)
		cmd->result = DID_ERROR << 16;
		break;
		}

		} else if (scsi_status != SAM_STAT_TASK_SET_FULL &&
		scsi_status != SAM_STAT_BUSY) {

		/* Copy Sense Data into sense buffer. */
		qla4xxx_copy_sense(ha, sts_entry, srb);
		} else {
		/*
		* If RISC reports underrun and target does not
		* report it then we must have a lost frame, so
		* tell upper layer to retry it by reporting a
		* bus busy.
		*/
		if ((sts_entry->iscsiFlags &
		ISCSI_FLAG_RESIDUAL_UNDER) == 0) {
		cmd->result = DID_BUS_BUSY << 16;
		} else if ((scsi_bufflen(cmd) - residual) <
		cmd->underflow) {
		/*
		* Handle mid-layer underflow???
		* The firmware reports UNDERRUN, but the target does
		* not report it:
		*
		* For kernels less than 2.4, the driver must
		* return an error if an underflow is detected.
		* For kernels equal-to and above 2.4, the
		* mid-layer will appearantly handle the
		* underflow by detecting the residual count --
		* unfortunately, we do not see where this is
		* actually being done. In the interim, we
		* will return DID_ERROR.
		* scsi_status \| host_byte device_byte
		* \| (19:16) (7:0)
		* ============= \| ========= ===========
		* TASK_SET_FULL \| DID_OK scsi_status
		* BUSY \| DID_OK scsi_status
		* ALL OTHERS \| DID_ERROR scsi_status
		*
		* Note: If scsi_status is task set full or busy,
		* then this else if would fall thru to check the
		* scsi_status and return DID_OK.
		*/
		DEBUG2(printk("scsi%ld:%d:%d:%d: %s: "
		"Mid-layer Data underrun1, "
		"xferlen = 0x%x, "
		"residual = 0x%x\n", ha->host_no,

		DEBUG2(ql4_printk(KERN_INFO, ha,
		"scsi%ld:%d:%d:%d: %s: Dropped frame(s) detected (0x%x of 0x%x bytes).\n",
		ha->host_no,
		cmd->device->channel,
		cmd->device->id,
		cmd->device->lun, __func__,
		scsi_bufflen(cmd), residual));
		residual,
		scsi_bufflen(cmd)));

		cmd->result = DID_ERROR << 16;
		} else {
		cmd->result = DID_OK << 16;
		}
		cmd->result = DID_ERROR << 16 \| scsi_status;
		goto check_scsi_status;
		}

		cmd->result = DID_OK << 16 \| scsi_status;

		check_scsi_status:
		if (scsi_status == SAM_STAT_CHECK_CONDITION)
		qla4xxx_copy_sense(ha, sts_entry, srb);

		break;

		case SCS_DEVICE_LOGGED_OUT: