qla2xxx: Check for device state before unloading the driver.

During hot swap of PCI device, there can be PCI error on device,
during normal driver unload. The race between normal driver unload and
driver unload due to PCI error, can lead to system crash.Fix is to check
if there is unload going on and allow that function to unload the driver.

Signed-off-by: Sawan Chandak <sawan.chandak@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_dbg.c

@@ -14,7 +14,7 @@
  * | Module Init and Probe        |       0x018f       | 0x0146         |
  * |                              |                    | 0x015b-0x0160	|
  * |                              |                    | 0x016e		|
- * | Mailbox commands             |       0x1192       |		|
+ * | Mailbox commands             |       0x1191       | 		|
  * |                              |                    |		|
  * | Device Discovery             |       0x2003       | 0x2016		|
  * |                              |                    | 0x2011-0x2012, |

drivers/scsi/qla2xxx/qla_def.h

@@ -3658,6 +3658,7 @@ typedef struct scsi_qla_host {
 #define PFLG_DISCONNECTED	0	/* PCI device removed */
 #define PFLG_DRIVER_REMOVING	1	/* PCI driver .remove */
 #define PFLG_DRIVER_PROBING	2	/* PCI driver .probe */
+#define PCI_ERR			30
 
 	uint32_t	device_flags;
 #define SWITCH_FOUND		BIT_0

drivers/scsi/qla2xxx/qla_mbx.c

@@ -64,6 +64,13 @@ qla2x00_mailbox_command(scsi_qla_host_t *vha, mbx_cmd_t *mcp)
 		return QLA_FUNCTION_TIMEOUT;
 	}
 
+	 /* if PCI error, then avoid mbx processing.*/
+	 if (test_bit(PCI_ERR, &base_vha->dpc_flags)) {
+		ql_log(ql_log_warn, vha, 0x1191,
+		    "PCI error, exiting.\n");
+		return QLA_FUNCTION_TIMEOUT;
+	 }
+
 	reg = ha->iobase;
 	io_lock_on = base_vha->flags.init_done;
 
@@ -266,6 +273,7 @@ qla2x00_mailbox_command(scsi_qla_host_t *vha, mbx_cmd_t *mcp)
 
 		uint16_t mb0;
 		uint32_t ictrl;
+		uint16_t        w;
 
 		if (IS_FWI2_CAPABLE(ha)) {
 			mb0 = RD_REG_WORD(&reg->isp24.mailbox0);
@@ -279,15 +287,32 @@ qla2x00_mailbox_command(scsi_qla_host_t *vha, mbx_cmd_t *mcp)
 		    "mb[0]=0x%x\n", command, ictrl, jiffies, mb0);
 		ql_dump_regs(ql_dbg_mbx + ql_dbg_buffer, vha, 0x1019);
 
-		/*
-		 * Attempt to capture a firmware dump for further analysis
-		 * of the current firmware state.  We do not need to do this
-		 * if we are intentionally generating a dump.
-		 */
-		if (mcp->mb[0] != MBC_GEN_SYSTEM_ERROR)
-			ha->isp_ops->fw_dump(vha, 0);
+		/* Capture FW dump only, if PCI device active */
+		if (!pci_channel_offline(vha->hw->pdev)) {
+			pci_read_config_word(ha->pdev, PCI_VENDOR_ID, &w);
+			if (w == 0xffff || ictrl == 0xffffffff) {
+				/* This is special case if there is unload
+				 * of driver happening and if PCI device go
+				 * into bad state due to PCI error condition
+				 * then only PCI ERR flag would be set.
+				 * we will do premature exit for above case.
+				 */
+				if (test_bit(UNLOADING, &base_vha->dpc_flags))
+					set_bit(PCI_ERR, &base_vha->dpc_flags);
+				ha->flags.mbox_busy = 0;
+				rval = QLA_FUNCTION_TIMEOUT;
+				goto premature_exit;
+			}
 
-		rval = QLA_FUNCTION_TIMEOUT;
+			/* Attempt to capture firmware dump for further
+			 * anallysis of the current formware state. we do not
+			 * need to do this if we are intentionally generating
+			 * a dump
+			 */
+			if (mcp->mb[0] != MBC_GEN_SYSTEM_ERROR)
+				ha->isp_ops->fw_dump(vha, 0);
+			rval = QLA_FUNCTION_TIMEOUT;
+		 }
 	}
 
 	ha->flags.mbox_busy = 0;

drivers/scsi/qla2xxx/qla_os.c

@@ -897,12 +897,16 @@ static void
 qla2x00_wait_for_hba_ready(scsi_qla_host_t *vha)
 {
 	struct qla_hw_data *ha = vha->hw;
+	scsi_qla_host_t *base_vha = pci_get_drvdata(ha->pdev);
 
 	while (((qla2x00_reset_active(vha)) || ha->dpc_active ||
 	    ha->flags.mbox_busy) ||
 		test_bit(FX00_RESET_RECOVERY, &vha->dpc_flags) ||
-		test_bit(FX00_TARGET_SCAN, &vha->dpc_flags))
+		test_bit(FX00_TARGET_SCAN, &vha->dpc_flags)) {
+			if (test_bit(UNLOADING, &base_vha->dpc_flags))
+				break;
 		msleep(1000);
+	}
 }
 
 int
@@ -2954,10 +2958,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	ha = NULL;
 
 probe_out:
-	pci_disable_pcie_error_reporting(pdev);
 	pci_disable_device(pdev);
-	if (test_bit(UNLOADING, &base_vha->dpc_flags))
-		return -ENODEV;
 	return ret;
 }
 
@@ -3138,6 +3139,12 @@ qla2x00_remove_one(struct pci_dev *pdev)
 
 	qla2x00_wait_for_hba_ready(base_vha);
 
+	/* if UNLOAD flag is already set, then continue unload,
+	 * where it was set first.
+	 */
+	if (test_bit(UNLOADING, &base_vha->dpc_flags))
+		return;
+
 	set_bit(UNLOADING, &base_vha->dpc_flags);
 
 	if (IS_QLAFX00(ha))
@@ -4917,6 +4924,12 @@ qla2x00_disable_board_on_pci_error(struct work_struct *work)
 	struct pci_dev *pdev = ha->pdev;
 	scsi_qla_host_t *base_vha = pci_get_drvdata(ha->pdev);
 
+	/* if UNLOAD flag is already set, then continue unload,
+	 * where it was set first.
+	 */
+	if (test_bit(UNLOADING, &base_vha->dpc_flags))
+		return;
+
 	ql_log(ql_log_warn, base_vha, 0x015b,
 	    "Disabling adapter.\n");