Commit 24c14200 authored by Lalit Chandivade's avatar Lalit Chandivade Committed by James Bottomley
Browse files

[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: default avatarLalit Chandivade <lalit.chandivade@qlogic.com>
Signed-off-by: default avatarTej Parkash <tej.parkash@qlogic.com>
Signed-off-by: default avatarVikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames 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:

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