scsi: hisi_sas: Fix the conflict between dev gone and host reset
There is a possible conflict when a device is removed and host reset occurs
concurrently.
The reason is that then the device is notified as gone, we try to clear the
ITCT, which is notified via an interrupt. The dev gone function pends on
this event with a completion, which is completed when the ITCT interrupt
occurs.
But host reset will disable all interrupts, the wait_for_completion() may
wait indefinitely.
This patch adds an semaphore to synchronise this two processes. The
semaphore is taken by the host reset as the basis of synchronising.
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index 7052a5d..78e5a92 100644
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -277,6 +277,7 @@
int n_phy;
spinlock_t lock;
+ struct semaphore sem;
struct timer_list timer;
struct workqueue_struct *wq;
diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 1c424bb..823386f 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -914,7 +914,9 @@
hisi_sas_dereg_device(hisi_hba, device);
+ down(&hisi_hba->sem);
hisi_hba->hw->clear_itct(hisi_hba, sas_dev);
+ up(&hisi_hba->sem);
device->lldd_dev = NULL;
}
@@ -1364,6 +1366,7 @@
if (test_and_set_bit(HISI_SAS_RESET_BIT, &hisi_hba->flags))
return -1;
+ down(&hisi_hba->sem);
dev_info(dev, "controller resetting...\n");
old_state = hisi_hba->hw->get_phys_state(hisi_hba);
@@ -1378,6 +1381,7 @@
if (rc) {
dev_warn(dev, "controller reset failed (%d)\n", rc);
clear_bit(HISI_SAS_REJECT_CMD_BIT, &hisi_hba->flags);
+ up(&hisi_hba->sem);
scsi_unblock_requests(shost);
goto out;
}
@@ -1388,6 +1392,7 @@
hisi_hba->hw->phys_init(hisi_hba);
msleep(1000);
hisi_sas_refresh_port_id(hisi_hba);
+ up(&hisi_hba->sem);
if (hisi_hba->reject_stp_links_msk)
hisi_sas_terminate_stp_reject(hisi_hba);
@@ -2016,6 +2021,7 @@
struct device *dev = hisi_hba->dev;
int i, s, max_command_entries = hisi_hba->hw->max_command_entries;
+ sema_init(&hisi_hba->sem, 1);
spin_lock_init(&hisi_hba->lock);
for (i = 0; i < hisi_hba->n_phy; i++) {
hisi_sas_phy_init(hisi_hba, i);