Re: lpfc PCIe error recoveyr

Re: lpfc PCIe error recoveyr

[Linas Vepstas]

On Tue, Jan 09, 2007 at 10:00:09AM -0500, Bino.Sebastian@Emulex.Com wrote:
> Hi Linas,
> 	Following is the latest lpfc driver patch we are testing in the 
> Emulex lab for PCI error recovery. This patch looks good on a Power5 
> platform. 

Yes, it seemed to survive a few hours of testting fine. I did see one
interesting thing, namely a softlockup. I attribute this to the fact
that I'd queued up a lot of heavy file i/o, issued a sync, which
typically takes more than a few seconds on the test sytem, and then 
injected the artificial PCI error. After about ten seconds, I got the 
softlockup, but after another 10-20 seconds, things seemed back to
normal. So I don't consider this an actual error, but thought 
it was interesting.

The actual stack trace was

BUG: soft lockup detected on CPU#2!
Call Trace:
[C00000000253D470] [C00000000000F8C8] .show_stack+0x68/0x1b0 (unreliable)
[C00000000253D510] [C00000000008E770] .softlockup_tick+0xec/0x124
[C00000000253D5B0] [C00000000006957C] .run_local_timers+0x1c/0x30
[C00000000253D630] [C000000000023C18] .timer_interrupt+0xb8/0x4a4
[C00000000253D710] [C000000000003578] decrementer_common+0xf8/0x100
--- Exception: 901 at .local_irq_restore+0x3c/0x40
    LR = ._spin_unlock_irqrestore+0x24/0x3c
[C00000000253DA00] [C00000000046D574] ._spin_unlock_irqrestore+0x18/0x3c (unreliable)
[C00000000253DA90] [C00000000031BBA0] .scsi_dispatch_cmd+0x25c/0x2e4
[C00000000253DB30] [C0000000003227CC] .scsi_request_fn+0x2c4/0x3c0
[C00000000253DBE0] [C00000000021ADF8] .__generic_unplug_device+0x54/0x6c
[C00000000253DC60] [C000000000216D34] .elv_insert+0x240/0x268
[C00000000253DD00] [C00000000021A224] .blk_requeue_request+0x38/0x54
[C00000000253DD90] [C00000000032282C] .scsi_request_fn+0x324/0x3c0
[C00000000253DE40] [C00000000021ADF8] .__generic_unplug_device+0x54/0x6c
[C00000000253DEC0] [C000000000216D34] .elv_insert+0x240/0x268
[C00000000253DF60] [C00000000021A224] .blk_requeue_request+0x38/0x54
[C00000000253DFF0] [C00000000032282C] .scsi_request_fn+0x324/0x3c0
[C00000000253E0A0] [C00000000021ADF8] .__generic_unplug_device+0x54/0x6c
etc.

> However, on a Power4 architecture there are errors reported
> in upper layer (we discussed this in one of earlier emails) followed 
> by SCSI errors.

I'm trying to investigate now.

The patch you sent out got garbled, so I'm reposting below.

----

This patch adds PCI Error recovery support to the
Emulex Lightpulse Fibrechannel (lpfc) SCSI device driver.
Lightly tested at this point, works.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Bino.Sebastian@Emulex.Com
Cc: James Smart <james.smart@emulex.com>

----

 drivers/scsi/lpfc/lpfc_init.c |   96 ++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/lpfc/lpfc_sli.c  |   12 +++++
 2 files changed, 108 insertions(+)

Index: linux-2.6.20-rc4/drivers/scsi/lpfc/lpfc_init.c
===================================================================
--- linux-2.6.20-rc4.orig/drivers/scsi/lpfc/lpfc_init.c	2007-01-10 12:30:01.000000000 -0600
+++ linux-2.6.20-rc4/drivers/scsi/lpfc/lpfc_init.c	2007-01-10 12:34:27.000000000 -0600
@@ -518,6 +518,10 @@ lpfc_handle_eratt(struct lpfc_hba * phba
 	struct lpfc_sli *psli = &phba->sli;
 	struct lpfc_sli_ring  *pring;
 	uint32_t event_data;
+	/* If the pci channel is offline, ignore possible errors,
+	 * since we cannot communicate with the pci card anyway. */
+	if (pci_channel_offline(phba->pcidev))
+		return;
 
 	if (phba->work_hs & HS_FFER6 ||
 	    phba->work_hs & HS_FFER5) {
@@ -1797,6 +1801,91 @@ lpfc_pci_remove_one(struct pci_dev *pdev
 	pci_set_drvdata(pdev, NULL);
 }
 
+/**
+ * lpfc_io_error_detected - called when PCI error is detected
+ * @pdev: Pointer to PCI device
+ * @state: The current pci conneection state
+ *
+ * This function is called after a PCI bus error affecting
+ * this device has been detected.
+ */
+static pci_ers_result_t lpfc_io_error_detected(struct pci_dev *pdev,
+				pci_channel_state_t state)
+{
+	struct Scsi_Host *host = pci_get_drvdata(pdev);
+	struct lpfc_hba *phba = (struct lpfc_hba *)host->hostdata;
+	struct lpfc_sli *psli = &phba->sli;
+	struct lpfc_sli_ring  *pring;
+
+	if (state == pci_channel_io_perm_failure) {
+		lpfc_pci_remove_one(pdev);
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+	pci_disable_device(pdev);
+	/*
+	 * There may be I/Os dropped by the firmware.
+	 * Error iocb (I/O) on txcmplq and let the SCSI layer
+	 * retry it after re-establishing link.
+	 */
+	pring = &psli->ring[psli->fcp_ring];
+	lpfc_sli_abort_iocb_ring(phba, pring);
+
+	/* Request a slot reset. */
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
+/**
+ * lpfc_io_slot_reset - called after the pci bus has been reset.
+ * @pdev: Pointer to PCI device
+ *
+ * Restart the card from scratch, as if from a cold-boot.
+ */
+static pci_ers_result_t lpfc_io_slot_reset(struct pci_dev *pdev)
+{
+	struct Scsi_Host *host = pci_get_drvdata(pdev);
+	struct lpfc_hba *phba = (struct lpfc_hba *)host->hostdata;
+	struct lpfc_sli *psli = &phba->sli;
+
+	dev_printk(KERN_INFO, &pdev->dev, "recovering from a slot reset.\n");
+	if (pci_enable_device(pdev)) {
+		printk(KERN_ERR "lpfc: Cannot re-enable "
+			"PCI device after reset.\n");
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
+	pci_set_master(pdev);
+
+	/* Re-establishing Link */
+	spin_lock_irq(phba->host->host_lock);
+	phba->fc_flag |= FC_ESTABLISH_LINK;
+	psli->sli_flag &= ~LPFC_SLI2_ACTIVE;
+	spin_unlock_irq(phba->host->host_lock);
+
+
+	/* Take device offline; this will perform cleanup */
+	lpfc_offline(phba);
+	lpfc_sli_brdrestart(phba);
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+/**
+ * lpfc_io_resume - called when traffic can start flowing again.
+ * @pdev: Pointer to PCI device
+ *
+ * This callback is called when the error recovery driver tells us that
+ * its OK to resume normal operation.
+ */
+static void lpfc_io_resume(struct pci_dev *pdev)
+{
+	struct Scsi_Host *host = pci_get_drvdata(pdev);
+	struct lpfc_hba *phba = (struct lpfc_hba *)host->hostdata;
+
+	if (lpfc_online(phba) == 0) {
+		mod_timer(&phba->fc_estabtmo, jiffies + HZ * 60);
+	}
+}
+
 static struct pci_device_id lpfc_id_table[] = {
 	{PCI_VENDOR_ID_EMULEX, PCI_DEVICE_ID_VIPER,
 		PCI_ANY_ID, PCI_ANY_ID, },
@@ -1857,11 +1946,18 @@ static struct pci_device_id lpfc_id_tabl
 
 MODULE_DEVICE_TABLE(pci, lpfc_id_table);
 
+static struct pci_error_handlers lpfc_err_handler = {
+	.error_detected = lpfc_io_error_detected,
+	.slot_reset = lpfc_io_slot_reset,
+	.resume = lpfc_io_resume,
+};
+
 static struct pci_driver lpfc_driver = {
 	.name		= LPFC_DRIVER_NAME,
 	.id_table	= lpfc_id_table,
 	.probe		= lpfc_pci_probe_one,
 	.remove		= __devexit_p(lpfc_pci_remove_one),
+	.err_handler = &lpfc_err_handler,
 };
 
 static int __init
Index: linux-2.6.20-rc4/drivers/scsi/lpfc/lpfc_sli.c
===================================================================
--- linux-2.6.20-rc4.orig/drivers/scsi/lpfc/lpfc_sli.c	2007-01-08 17:55:41.000000000 -0600
+++ linux-2.6.20-rc4/drivers/scsi/lpfc/lpfc_sli.c	2007-01-10 12:34:27.000000000 -0600
@@ -2104,6 +2104,10 @@ lpfc_sli_issue_mbox(struct lpfc_hba * ph
 	volatile uint32_t word0, ldata;
 	void __iomem *to_slim;
 
+	/* If the PCI channel is in offline state, do not post mbox. */
+	if (unlikely(pci_channel_offline(phba->pcidev)))
+		return MBX_NOT_FINISHED;
+
 	psli = &phba->sli;
 
 	spin_lock_irqsave(phba->host->host_lock, drvr_flag);
@@ -2407,6 +2411,10 @@ lpfc_sli_issue_iocb(struct lpfc_hba *phb
 	struct lpfc_iocbq *nextiocb;
 	IOCB_t *iocb;
 
+	/* If the PCI channel is in offline state, do not post iocbs. */
+	if (unlikely(pci_channel_offline(phba->pcidev)))
+		return IOCB_ERROR;
+
 	/*
 	 * We should never get an IOCB if we are in a < LINK_DOWN state
 	 */
@@ -3154,6 +3162,10 @@ lpfc_intr_handler(int irq, void *dev_id)
 	if (unlikely(!phba))
 		return IRQ_NONE;
 
+	/* If the pci channel is offline, ignore all the interrupts. */
+	if (unlikely(pci_channel_offline(phba->pcidev)))
+		return IRQ_NONE;
+
 	phba->sli.slistat.sli_intr++;
 
 	/*

Re: lpfc PCIe error recovey

[Linas Vepstas]

On Wed, Jan 10, 2007 at 04:59:39PM -0600, linas wrote:
> 
> > However, on a Power4 architecture there are errors reported
> > in upper layer (we discussed this in one of earlier emails) followed 
> > by SCSI errors.
> 
> I'm trying to investigate now.

I found two distinct power4 bugs. I posted a patch for one yesterday,
under the subject heading 

  [PATCH] Urgent: powerpc 2.6.20-rc4 dma broken on non-LPAR pseries

This affects only recent mainline kernels; it would not affect
older or distro kernels.   

The other patch is attached below.  After some more testing,
I'll submit to mainline.

--linas


Subject: [PATCH] pSeries: EEH improperly enabled for some Power4 systems

It appears that EEH is improperly enabled for some Power4 systems.
On these systems, the ibm,set-eeh-option returns a value of success
even when EEH is not supported on the given node. Thus, an explicit
check for support is required.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com> 

----
 arch/powerpc/platforms/pseries/eeh.c |   19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

Index: linux-2.6.20-rc4/arch/powerpc/platforms/pseries/eeh.c
===================================================================
--- linux-2.6.20-rc4.orig/arch/powerpc/platforms/pseries/eeh.c	2007-01-11 14:15:02.000000000 -0600
+++ linux-2.6.20-rc4/arch/powerpc/platforms/pseries/eeh.c	2007-01-11 15:14:39.000000000 -0600
@@ -748,6 +748,7 @@ struct eeh_early_enable_info {
 /* Enable eeh for the given device node. */
 static void *early_enable_eeh(struct device_node *dn, void *data)
 {
+	unsigned int rets[3];
 	struct eeh_early_enable_info *info = data;
 	int ret;
 	const char *status = get_property(dn, "status", NULL);
@@ -804,16 +805,14 @@ static void *early_enable_eeh(struct dev
 		                regs[0], info->buid_hi, info->buid_lo,
 		                EEH_ENABLE);
 
+		enable = 0;
 		if (ret == 0) {
-			eeh_subsystem_enabled = 1;
-			pdn->eeh_mode |= EEH_MODE_SUPPORTED;
 			pdn->eeh_config_addr = regs[0];
 
 			/* If the newer, better, ibm,get-config-addr-info is supported, 
 			 * then use that instead. */
 			pdn->eeh_pe_config_addr = 0;
 			if (ibm_get_config_addr_info != RTAS_UNKNOWN_SERVICE) {
-				unsigned int rets[2];
 				ret = rtas_call (ibm_get_config_addr_info, 4, 2, rets, 
 					pdn->eeh_config_addr, 
 					info->buid_hi, info->buid_lo,
@@ -821,6 +820,20 @@ static void *early_enable_eeh(struct dev
 				if (ret == 0)
 					pdn->eeh_pe_config_addr = rets[0];
 			}
+
+			/* Some older systems (Power4) allow the
+			 * ibm,set-eeh-option call to succeed even on nodes
+			 * where EEH is not supported. Verify support
+			 * explicitly. */
+			ret = read_slot_reset_state(pdn, rets);
+			if ((ret == 0) && (rets[1] == 1))
+				enable = 1;
+		}
+
+		if (enable) {
+			eeh_subsystem_enabled = 1;
+			pdn->eeh_mode |= EEH_MODE_SUPPORTED;
+
 #ifdef DEBUG
 			printk(KERN_DEBUG "EEH: %s: eeh enabled, config=%x pe_config=%x\n",
 			       dn->full_name, pdn->eeh_config_addr, pdn->eeh_pe_config_addr);