[SCSI] pm8001: deficient responses to IO_XFER_ERROR_BREAK and IO_XFER_OPEN_RETRY_TIMEOUT

IO_XFER_ERROR_BREAK and IO_XFER_OPEN_RETRY_TIMEOUT are deficient of the
required actions as outlined in the programming manual for the pm8001. Due to
the overlapping code requirements of these recovery responses, we found it
necessary to bundle them together into one patch.

When a break is received during the command phase (ssp_completion), this is a
result of a timeout or interruption on the bus. Logic suggests that we should
retry the command.

When a break is received during the data-phase (ssp_event), the task must be
aborted on the target or it will retain a data-phase lock turning the target
reticent to all future media commands yet will successfully respond to TUR,
INQUIRY and ABORT leading eventually to target failure through several
abort-cycle loops.

The open retry interval is exceedingly short resulting in occasional target
drop-off during expander resets or when targets push-back during bad-block
remapping. Increased effective timeout from 130ms to 1.5 seconds for each try
so as to trigger after the administrative inquiry/tur timeout in the scsi
subsystem to keep error-recovery harmonics to a minimum.

When an open retry timeout event is received, the action required by the
targets is to issue an abort for the outstanding command then logic suggests
we retry the command as this state is usually an indication of a credit block
or busy condition on the target.

We hijacked the pm8001_handle_event work queue handler so that it will handle
task as an argument instead of device for the workers in support of the
deferred handling outlined above.

Moderate to Heavy bad-path testing on a 2.6.32 vintage kernel, compile-testing
on scsi-misc-2.6 kernel ...
Signed-off-by: Mark Salyzyn <mark_salyzyn@xyratex.com>
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/pm8001/pm8001_hwi.c

@@ -622,7 +622,8 @@ static int __devinit pm8001_chip_init(struct pm8001_hba_info *pm8001_ha)
 	update_inbnd_queue_table(pm8001_ha, 0);
 	update_outbnd_queue_table(pm8001_ha, 0);
 	mpi_set_phys_g3_with_ssc(pm8001_ha, 0);
-	mpi_set_open_retry_interval_reg(pm8001_ha, 7);
+	/* 7->130ms, 34->500ms, 119->1.5s */
+	mpi_set_open_retry_interval_reg(pm8001_ha, 119);
 	/* notify firmware update finished and check initialization status */
 	if (0 == mpi_init_check(pm8001_ha)) {
 		PM8001_INIT_DBG(pm8001_ha,
@@ -1421,24 +1422,191 @@ static void pm8001_work_fn(struct work_struct *work)
 	struct pm8001_device *pm8001_dev;
 	struct domain_device *dev;
 
+	/*
+	 * So far, all users of this stash an associated structure here.
+	 * If we get here, and this pointer is null, then the action
+	 * was cancelled. This nullification happens when the device
+	 * goes away.
+	 */
+	pm8001_dev = pw->data; /* Most stash device structure */
+	if ((pm8001_dev == NULL)
+	 || ((pw->handler != IO_XFER_ERROR_BREAK)
+	  && (pm8001_dev->dev_type == NO_DEVICE))) {
+		kfree(pw);
+		return;
+	}
+
 	switch (pw->handler) {
+	case IO_XFER_ERROR_BREAK:
+	{	/* This one stashes the sas_task instead */
+		struct sas_task *t = (struct sas_task *)pm8001_dev;
+		u32 tag;
+		struct pm8001_ccb_info *ccb;
+		struct pm8001_hba_info *pm8001_ha = pw->pm8001_ha;
+		unsigned long flags, flags1;
+		struct task_status_struct *ts;
+		int i;
+
+		if (pm8001_query_task(t) == TMF_RESP_FUNC_SUCC)
+			break; /* Task still on lu */
+		spin_lock_irqsave(&pm8001_ha->lock, flags);
+
+		spin_lock_irqsave(&t->task_state_lock, flags1);
+		if (unlikely((t->task_state_flags & SAS_TASK_STATE_DONE))) {
+			spin_unlock_irqrestore(&t->task_state_lock, flags1);
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			break; /* Task got completed by another */
+		}
+		spin_unlock_irqrestore(&t->task_state_lock, flags1);
+
+		/* Search for a possible ccb that matches the task */
+		for (i = 0; ccb = NULL, i < PM8001_MAX_CCB; i++) {
+			ccb = &pm8001_ha->ccb_info[i];
+			tag = ccb->ccb_tag;
+			if ((tag != 0xFFFFFFFF) && (ccb->task == t))
+				break;
+		}
+		if (!ccb) {
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			break; /* Task got freed by another */
+		}
+		ts = &t->task_status;
+		ts->resp = SAS_TASK_COMPLETE;
+		/* Force the midlayer to retry */
+		ts->stat = SAS_QUEUE_FULL;
+		pm8001_dev = ccb->device;
+		if (pm8001_dev)
+			pm8001_dev->running_req--;
+		spin_lock_irqsave(&t->task_state_lock, flags1);
+		t->task_state_flags &= ~SAS_TASK_STATE_PENDING;
+		t->task_state_flags &= ~SAS_TASK_AT_INITIATOR;
+		t->task_state_flags |= SAS_TASK_STATE_DONE;
+		if (unlikely((t->task_state_flags & SAS_TASK_STATE_ABORTED))) {
+			spin_unlock_irqrestore(&t->task_state_lock, flags1);
+			PM8001_FAIL_DBG(pm8001_ha, pm8001_printk("task 0x%p"
+				" done with event 0x%x resp 0x%x stat 0x%x but"
+				" aborted by upper layer!\n",
+				t, pw->handler, ts->resp, ts->stat));
+			pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+		} else {
+			spin_unlock_irqrestore(&t->task_state_lock, flags1);
+			pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
+			mb();/* in order to force CPU ordering */
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			t->task_done(t);
+		}
+	}	break;
+	case IO_XFER_OPEN_RETRY_TIMEOUT:
+	{	/* This one stashes the sas_task instead */
+		struct sas_task *t = (struct sas_task *)pm8001_dev;
+		u32 tag;
+		struct pm8001_ccb_info *ccb;
+		struct pm8001_hba_info *pm8001_ha = pw->pm8001_ha;
+		unsigned long flags, flags1;
+		int i, ret = 0;
+
+		PM8001_IO_DBG(pm8001_ha,
+			pm8001_printk("IO_XFER_OPEN_RETRY_TIMEOUT\n"));
+
+		ret = pm8001_query_task(t);
+
+		PM8001_IO_DBG(pm8001_ha,
+			switch (ret) {
+			case TMF_RESP_FUNC_SUCC:
+				pm8001_printk("...Task on lu\n");
+				break;
+
+			case TMF_RESP_FUNC_COMPLETE:
+				pm8001_printk("...Task NOT on lu\n");
+				break;
+
+			default:
+				pm8001_printk("...query task failed!!!\n");
+				break;
+			});
+
+		spin_lock_irqsave(&pm8001_ha->lock, flags);
+
+		spin_lock_irqsave(&t->task_state_lock, flags1);
+
+		if (unlikely((t->task_state_flags & SAS_TASK_STATE_DONE))) {
+			spin_unlock_irqrestore(&t->task_state_lock, flags1);
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			if (ret == TMF_RESP_FUNC_SUCC) /* task on lu */
+				(void)pm8001_abort_task(t);
+			break; /* Task got completed by another */
+		}
+
+		spin_unlock_irqrestore(&t->task_state_lock, flags1);
+
+		/* Search for a possible ccb that matches the task */
+		for (i = 0; ccb = NULL, i < PM8001_MAX_CCB; i++) {
+			ccb = &pm8001_ha->ccb_info[i];
+			tag = ccb->ccb_tag;
+			if ((tag != 0xFFFFFFFF) && (ccb->task == t))
+				break;
+		}
+		if (!ccb) {
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			if (ret == TMF_RESP_FUNC_SUCC) /* task on lu */
+				(void)pm8001_abort_task(t);
+			break; /* Task got freed by another */
+		}
+
+		pm8001_dev = ccb->device;
+		dev = pm8001_dev->sas_device;
+
+		switch (ret) {
+		case TMF_RESP_FUNC_SUCC: /* task on lu */
+			ccb->open_retry = 1; /* Snub completion */
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			ret = pm8001_abort_task(t);
+			ccb->open_retry = 0;
+			switch (ret) {
+			case TMF_RESP_FUNC_SUCC:
+			case TMF_RESP_FUNC_COMPLETE:
+				break;
+			default: /* device misbehavior */
+				ret = TMF_RESP_FUNC_FAILED;
+				PM8001_IO_DBG(pm8001_ha,
+					pm8001_printk("...Reset phy\n"));
+				pm8001_I_T_nexus_reset(dev);
+				break;
+			}
+			break;
+
+		case TMF_RESP_FUNC_COMPLETE: /* task not on lu */
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			/* Do we need to abort the task locally? */
+			break;
+
+		default: /* device misbehavior */
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			ret = TMF_RESP_FUNC_FAILED;
+			PM8001_IO_DBG(pm8001_ha,
+				pm8001_printk("...Reset phy\n"));
+			pm8001_I_T_nexus_reset(dev);
+		}
+
+		if (ret == TMF_RESP_FUNC_FAILED)
+			t = NULL;
+		pm8001_open_reject_retry(pm8001_ha, t, pm8001_dev);
+		PM8001_IO_DBG(pm8001_ha, pm8001_printk("...Complete\n"));
+	}	break;
 	case IO_OPEN_CNX_ERROR_IT_NEXUS_LOSS:
-		pm8001_dev = pw->data;
 		dev = pm8001_dev->sas_device;
 		pm8001_I_T_nexus_reset(dev);
 		break;
 	case IO_OPEN_CNX_ERROR_STP_RESOURCES_BUSY:
-		pm8001_dev = pw->data;
 		dev = pm8001_dev->sas_device;
 		pm8001_I_T_nexus_reset(dev);
 		break;
 	case IO_DS_IN_ERROR:
-		pm8001_dev = pw->data;
 		dev = pm8001_dev->sas_device;
 		pm8001_I_T_nexus_reset(dev);
 		break;
 	case IO_DS_NON_OPERATIONAL:
-		pm8001_dev = pw->data;
 		dev = pm8001_dev->sas_device;
 		pm8001_I_T_nexus_reset(dev);
 		break;
@@ -1493,6 +1661,11 @@ mpi_ssp_completion(struct pm8001_hba_info *pm8001_ha , void *piomb)
 	status = le32_to_cpu(psspPayload->status);
 	tag = le32_to_cpu(psspPayload->tag);
 	ccb = &pm8001_ha->ccb_info[tag];
+	if ((status == IO_ABORTED) && ccb->open_retry) {
+		/* Being completed by another */
+		ccb->open_retry = 0;
+		return;
+	}
 	pm8001_dev = ccb->device;
 	param = le32_to_cpu(psspPayload->param);
 
@@ -1548,6 +1721,8 @@ mpi_ssp_completion(struct pm8001_hba_info *pm8001_ha , void *piomb)
 			pm8001_printk("IO_XFER_ERROR_BREAK\n"));
 		ts->resp = SAS_TASK_COMPLETE;
 		ts->stat = SAS_OPEN_REJECT;
+		/* Force the midlayer to retry */
+		ts->open_rej_reason = SAS_OREJ_RSVD_RETRY;
 		break;
 	case IO_XFER_ERROR_PHY_NOT_READY:
 		PM8001_IO_DBG(pm8001_ha,
@@ -1752,9 +1927,8 @@ static void mpi_ssp_event(struct pm8001_hba_info *pm8001_ha , void *piomb)
 	case IO_XFER_ERROR_BREAK:
 		PM8001_IO_DBG(pm8001_ha,
 			pm8001_printk("IO_XFER_ERROR_BREAK\n"));
-		ts->resp = SAS_TASK_COMPLETE;
-		ts->stat = SAS_INTERRUPTED;
-		break;
+		pm8001_handle_event(pm8001_ha, t, IO_XFER_ERROR_BREAK);
+		return;
 	case IO_XFER_ERROR_PHY_NOT_READY:
 		PM8001_IO_DBG(pm8001_ha,
 			pm8001_printk("IO_XFER_ERROR_PHY_NOT_READY\n"));
@@ -1833,10 +2007,8 @@ static void mpi_ssp_event(struct pm8001_hba_info *pm8001_ha , void *piomb)
 	case IO_XFER_OPEN_RETRY_TIMEOUT:
 		PM8001_IO_DBG(pm8001_ha,
 			pm8001_printk("IO_XFER_OPEN_RETRY_TIMEOUT\n"));
-		ts->resp = SAS_TASK_COMPLETE;
-		ts->stat = SAS_OPEN_REJECT;
-		ts->open_rej_reason = SAS_OREJ_RSVD_RETRY;
-		break;
+		pm8001_handle_event(pm8001_ha, t, IO_XFER_OPEN_RETRY_TIMEOUT);
+		return;
 	case IO_XFER_ERROR_UNEXPECTED_PHASE:
 		PM8001_IO_DBG(pm8001_ha,
 			pm8001_printk("IO_XFER_ERROR_UNEXPECTED_PHASE\n"));

drivers/scsi/pm8001/pm8001_sas.c

@@ -538,6 +538,7 @@ void pm8001_ccb_task_free(struct pm8001_hba_info *pm8001_ha,
 	task->lldd_task = NULL;
 	ccb->task = NULL;
 	ccb->ccb_tag = 0xFFFFFFFF;
+	ccb->open_retry = 0;
 	pm8001_ccb_free(pm8001_ha, ccb_idx);
 }
 
@@ -882,6 +883,77 @@ static int pm8001_issue_ssp_tmf(struct domain_device *dev,
 		tmf);
 }
 
+/* retry commands by ha, by task and/or by device */
+void pm8001_open_reject_retry(
+	struct pm8001_hba_info *pm8001_ha,
+	struct sas_task *task_to_close,
+	struct pm8001_device *device_to_close)
+{
+	int i;
+	unsigned long flags;
+
+	if (pm8001_ha == NULL)
+		return;
+
+	spin_lock_irqsave(&pm8001_ha->lock, flags);
+
+	for (i = 0; i < PM8001_MAX_CCB; i++) {
+		struct sas_task *task;
+		struct task_status_struct *ts;
+		struct pm8001_device *pm8001_dev;
+		unsigned long flags1;
+		u32 tag;
+		struct pm8001_ccb_info *ccb = &pm8001_ha->ccb_info[i];
+
+		pm8001_dev = ccb->device;
+		if (!pm8001_dev || (pm8001_dev->dev_type == NO_DEVICE))
+			continue;
+		if (!device_to_close) {
+			uintptr_t d = (uintptr_t)pm8001_dev
+					- (uintptr_t)&pm8001_ha->devices;
+			if (((d % sizeof(*pm8001_dev)) != 0)
+			 || ((d / sizeof(*pm8001_dev)) >= PM8001_MAX_DEVICES))
+				continue;
+		} else if (pm8001_dev != device_to_close)
+			continue;
+		tag = ccb->ccb_tag;
+		if (!tag || (tag == 0xFFFFFFFF))
+			continue;
+		task = ccb->task;
+		if (!task || !task->task_done)
+			continue;
+		if (task_to_close && (task != task_to_close))
+			continue;
+		ts = &task->task_status;
+		ts->resp = SAS_TASK_COMPLETE;
+		/* Force the midlayer to retry */
+		ts->stat = SAS_OPEN_REJECT;
+		ts->open_rej_reason = SAS_OREJ_RSVD_RETRY;
+		if (pm8001_dev)
+			pm8001_dev->running_req--;
+		spin_lock_irqsave(&task->task_state_lock, flags1);
+		task->task_state_flags &= ~SAS_TASK_STATE_PENDING;
+		task->task_state_flags &= ~SAS_TASK_AT_INITIATOR;
+		task->task_state_flags |= SAS_TASK_STATE_DONE;
+		if (unlikely((task->task_state_flags
+				& SAS_TASK_STATE_ABORTED))) {
+			spin_unlock_irqrestore(&task->task_state_lock,
+				flags1);
+			pm8001_ccb_task_free(pm8001_ha, task, ccb, tag);
+		} else {
+			spin_unlock_irqrestore(&task->task_state_lock,
+				flags1);
+			pm8001_ccb_task_free(pm8001_ha, task, ccb, tag);
+			mb();/* in order to force CPU ordering */
+			spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+			task->task_done(task);
+			spin_lock_irqsave(&pm8001_ha->lock, flags);
+		}
+	}
+
+	spin_unlock_irqrestore(&pm8001_ha->lock, flags);
+}
+
 /**
   * Standard mandates link reset for ATA  (type 0) and hard reset for
   * SSP (type 1) , only for RECOVERY

drivers/scsi/pm8001/pm8001_sas.h

@@ -235,6 +235,7 @@ struct pm8001_ccb_info {
 	struct pm8001_device	*device;
 	struct pm8001_prd	buf_prd[PM8001_MAX_DMA_SG];
 	struct fw_control_ex	*fw_control_context;
+	u8			open_retry;
 };
 
 struct mpi_mem {
@@ -484,6 +485,10 @@ void pm8001_dev_gone(struct domain_device *dev);
 int pm8001_lu_reset(struct domain_device *dev, u8 *lun);
 int pm8001_I_T_nexus_reset(struct domain_device *dev);
 int pm8001_query_task(struct sas_task *task);
+void pm8001_open_reject_retry(
+	struct pm8001_hba_info *pm8001_ha,
+	struct sas_task *task_to_close,
+	struct pm8001_device *device_to_close);
 int pm8001_mem_alloc(struct pci_dev *pdev, void **virt_addr,
 	dma_addr_t *pphys_addr, u32 *pphys_addr_hi, u32 *pphys_addr_lo,
 	u32 mem_size, u32 align);