qla2xxx: Prevent removal and board_disable race

Introduce mutual exclusion between the qla2xxx_remove_one PCI driver
callback and qla2x00_disable_board_on_pci_error, which is scheduled as
board_disable work by qla2x00_check_reg{32,16}_for_disconnect:

* Leave the driver-specific data attached to the underlying PCI device
intact in qla2x00_disable_board_on_pci_error, so that qla2x00_remove_one
has enough breadcrumbs to determine that any board_disable work has been
completed.

* In qla2xxx_remove_one, set a bit to prevent any subsequent
board_disable work from scheduling, then cancel and wait until pending
work has completed.

* Reuse the PCI device enable count check in qla2x00_remove_one to
determine if board_disable has occured. The original purpose of this
check was unnecessary since the driver remove function wasn't called
when the probe fails.

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>

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 4267ec6..1398818 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -3404,6 +3404,7 @@ typedef struct scsi_qla_host {
 
        unsigned long   pci_flags;
 #define PFLG_DISCONNECTED      0       /* PCI device removed */
+#define PFLG_DRIVER_REMOVING   1       /* PCI driver .remove */
 
        uint32_t        device_flags;
 #define SWITCH_FOUND           BIT_0

diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index fd75b91..341c64d 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -117,7 +117,8 @@ 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)) {
+               if (!test_and_set_bit(PFLG_DISCONNECTED, &vha->pci_flags) &&
+                   !test_bit(PFLG_DRIVER_REMOVING, &vha->pci_flags)) {
                        /*
                         * Schedule this (only once) on the default system
                         * workqueue so that all the adapter workqueues and the

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 3bfa89d..84d4df6 100644 (file)
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -3131,15 +3131,25 @@ qla2x00_remove_one(struct pci_dev *pdev)
        scsi_qla_host_t *base_vha;
        struct qla_hw_data  *ha;
 
+       base_vha = pci_get_drvdata(pdev);
+       ha = base_vha->hw;
+
+       /* Indicate device removal to prevent future board_disable and wait
+        * until any pending board_disable has completed. */
+       set_bit(PFLG_DRIVER_REMOVING, &base_vha->pci_flags);
+       cancel_work_sync(&ha->board_disable);
+
        /*
-        * If the PCI device is disabled that means that probe failed and any
-        * resources should be have cleaned up on probe exit.
+        * If the PCI device is disabled then there was a PCI-disconnect and
+        * qla2x00_disable_board_on_pci_error has taken care of most of the
+        * resources.
         */
-       if (!atomic_read(&pdev->enable_cnt))
+       if (!atomic_read(&pdev->enable_cnt)) {
+               scsi_host_put(base_vha->host);
+               kfree(ha);
+               pci_set_drvdata(pdev, NULL);
                return;
-
-       base_vha = pci_get_drvdata(pdev);
-       ha = base_vha->hw;
+       }
 
        qla2x00_wait_for_hba_ready(base_vha);
 
@@ -4799,18 +4809,15 @@ qla2x00_disable_board_on_pci_error(struct work_struct *work)
        qla82xx_md_free(base_vha);
        qla2x00_free_queues(ha);
 
-       scsi_host_put(base_vha->host);
-
        qla2x00_unmap_iobases(ha);
 
        pci_release_selected_regions(ha->pdev, ha->bars);
-       kfree(ha);
-       ha = NULL;
-
        pci_disable_pcie_error_reporting(pdev);
        pci_disable_device(pdev);
-       pci_set_drvdata(pdev, NULL);
 
+       /*
+        * Let qla2x00_remove_one cleanup qla_hw_data on device removal.
+        */
 }
 
 /**************************************************************************