[SCSI] pm8001: simplify workqueue usage

pm8001 manages its own list of pending works and cancel them on device
free.  It is unnecessarily complex and has a race condition - the
works are canceled but not synced, so the work could still be running
during and after the data structures are freed.

This patch simplifies workqueue usage.

* A driver specific workqueue pm8001_wq is created to serve these
  work items.

* To avoid confusion, the "queue" suffixes are dropped from work items
  and functions.

* Delayed queueing was never used.  pm8001_work now uses work_struct
  instead.

* The driver no longer keeps track of pending works.  All pm8001_works
  are queued to pm8001_wq and the workqueue is flushed as necessary.

flush_scheduled_work() usage is removed during conversion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
index 7f064f9ca82..bdb6b27dedd 100644
--- a/drivers/scsi/pm8001/pm8001_sas.h
+++ b/drivers/scsi/pm8001/pm8001_sas.h
@@ -50,6 +50,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/pci.h>
 #include <linux/interrupt.h>
+#include <linux/workqueue.h>
 #include <scsi/libsas.h>
 #include <scsi/scsi_tcq.h>
 #include <scsi/sas_ata.h>
@@ -379,18 +380,16 @@ struct pm8001_hba_info {
 #ifdef PM8001_USE_TASKLET
 	struct tasklet_struct	tasklet;
 #endif
-	struct list_head 	wq_list;
 	u32			logging_level;
 	u32			fw_status;
 	const struct firmware 	*fw_image;
 };
 
-struct pm8001_wq {
-	struct delayed_work work_q;
+struct pm8001_work {
+	struct work_struct work;
 	struct pm8001_hba_info *pm8001_ha;
 	void *data;
 	int handler;
-	struct list_head entry;
 };
 
 struct pm8001_fw_image_header {
@@ -460,6 +459,9 @@ struct fw_control_ex {
 	void			*param3;
 };
 
+/* pm8001 workqueue */
+extern struct workqueue_struct *pm8001_wq;
+
 /******************** function prototype *********************/
 int pm8001_tag_alloc(struct pm8001_hba_info *pm8001_ha, u32 *tag_out);
 void pm8001_tag_init(struct pm8001_hba_info *pm8001_ha);