qla2xxx: Prevent probe and board_disable race

The PCI register read checking introduced in commit fe1b806f
("qla2xxx: Disable adapter when we encounter a PCI disconnect") is
active during driver probe. Hold off scheduling any board removal until
the driver probe has completed. This ensures that the the board_disable
work structure is initialized and more importantly, avoids racing
qla2x00_probe_one.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/qla2xxx/qla_def.h

@@ -3405,6 +3405,7 @@ typedef struct scsi_qla_host {
 	unsigned long	pci_flags;
 #define PFLG_DISCONNECTED	0	/* PCI device removed */
 #define PFLG_DRIVER_REMOVING	1	/* PCI driver .remove */
+#define PFLG_DRIVER_PROBING	2	/* PCI driver .probe */
 
 	uint32_t	device_flags;
 #define SWITCH_FOUND		BIT_0

drivers/scsi/qla2xxx/qla_isr.c

@@ -118,7 +118,8 @@ qla2x00_check_reg32_for_disconnect(scsi_qla_host_t *vha, uint32_t reg)
 	/* Check for PCI disconnection */
 	if (reg == 0xffffffff) {
 		if (!test_and_set_bit(PFLG_DISCONNECTED, &vha->pci_flags) &&
-		    !test_bit(PFLG_DRIVER_REMOVING, &vha->pci_flags)) {
+		    !test_bit(PFLG_DRIVER_REMOVING, &vha->pci_flags) &&
+		    !test_bit(PFLG_DRIVER_PROBING, &vha->pci_flags)) {
 			/*
 			 * Schedule this (only once) on the default system
 			 * workqueue so that all the adapter workqueues and the

drivers/scsi/qla2xxx/qla_os.c

@@ -2632,6 +2632,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	}
 
 	pci_set_drvdata(pdev, base_vha);
+	set_bit(PFLG_DRIVER_PROBING, &base_vha->pci_flags);
 
 	host = base_vha->host;
 	base_vha->req = req;
@@ -2928,6 +2929,7 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	qlt_add_target(ha, base_vha);
 
+	clear_bit(PFLG_DRIVER_PROBING, &base_vha->pci_flags);
 	return 0;
 
 probe_init_failed: