scsi: hisi_sas: complete all tasklets prior to host reset

The CQ event is handled in tasklet context, and it could be delayed if
the system loading is high.

It is possible to run into some problems when executing a host reset
when cq_tasklet_vx_hw() is being executed.

So, prior to host reset, execute tasklet_kill() to ensure that all CQ
tasklets are complete.

Besides, as the function hisi_sas_wait_tasklets_done() is added to do
tasklet_kill(), this patch refactors some code where tasklet_kill() is
used.
Signed-off-by: NXiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas.h

@@ -426,4 +426,5 @@ extern void hisi_sas_slot_task_free(struct hisi_hba *hisi_hba,
 				    struct hisi_sas_slot *slot);
 extern void hisi_sas_init_mem(struct hisi_hba *hisi_hba);
 extern void hisi_sas_rst_work_handler(struct work_struct *work);
+extern void hisi_sas_kill_tasklets(struct hisi_hba *hisi_hba);
 #endif

drivers/scsi/hisi_sas/hisi_sas_main.c

@@ -1548,6 +1548,17 @@ void hisi_sas_phy_down(struct hisi_hba *hisi_hba, int phy_no, int rdy)
 }
 EXPORT_SYMBOL_GPL(hisi_sas_phy_down);
 
+void hisi_sas_kill_tasklets(struct hisi_hba *hisi_hba)
+{
+	int i;
+
+	for (i = 0; i < hisi_hba->queue_count; i++) {
+		struct hisi_sas_cq *cq = &hisi_hba->cq[i];
+
+		tasklet_kill(&cq->tasklet);
+	}
+}
+EXPORT_SYMBOL_GPL(hisi_sas_kill_tasklets);
 
 struct scsi_transport_template *hisi_sas_stt;
 EXPORT_SYMBOL_GPL(hisi_sas_stt);

drivers/scsi/hisi_sas/hisi_sas_v2_hw.c

@@ -3375,6 +3375,7 @@ static int soft_reset_v2_hw(struct hisi_hba *hisi_hba)
 
 	interrupt_disable_v2_hw(hisi_hba);
 	hisi_sas_write32(hisi_hba, DLVRY_QUEUE_ENABLE, 0x0);
+	hisi_sas_kill_tasklets(hisi_hba);
 
 	hisi_sas_stop_phys(hisi_hba);
 
@@ -3458,16 +3459,11 @@ static int hisi_sas_v2_remove(struct platform_device *pdev)
 {
 	struct sas_ha_struct *sha = platform_get_drvdata(pdev);
 	struct hisi_hba *hisi_hba = sha->lldd_ha;
-	int i;
 
 	if (timer_pending(&hisi_hba->timer))
 		del_timer(&hisi_hba->timer);
 
-	for (i = 0; i < hisi_hba->queue_count; i++) {
-		struct hisi_sas_cq *cq = &hisi_hba->cq[i];
-
-		tasklet_kill(&cq->tasklet);
-	}
+	hisi_sas_kill_tasklets(hisi_hba);
 
 	return hisi_sas_remove(pdev);
 }

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c

@@ -1768,6 +1768,7 @@ static int soft_reset_v3_hw(struct hisi_hba *hisi_hba)
 
 	interrupt_disable_v3_hw(hisi_hba);
 	hisi_sas_write32(hisi_hba, DLVRY_QUEUE_ENABLE, 0x0);
+	hisi_sas_kill_tasklets(hisi_hba);
 
 	hisi_sas_stop_phys(hisi_hba);
 
@@ -1977,7 +1978,6 @@ hisi_sas_v3_destroy_irqs(struct pci_dev *pdev, struct hisi_hba *hisi_hba)
 		struct hisi_sas_cq *cq = &hisi_hba->cq[i];
 
 		free_irq(pci_irq_vector(pdev, i+16), cq);
-		tasklet_kill(&cq->tasklet);
 	}
 	pci_free_irq_vectors(pdev);
 }
@@ -1993,6 +1993,7 @@ static void hisi_sas_v3_remove(struct pci_dev *pdev)
 	sas_remove_host(sha->core.shost);
 
 	hisi_sas_v3_destroy_irqs(pdev, hisi_hba);
+	hisi_sas_kill_tasklets(hisi_hba);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 	hisi_sas_free(hisi_hba);