media: Convert from tasklet to BH workqueue

The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.

This patch converts drivers/media/* from tasklet to BH workqueue.

Based on the work done by Tejun Heo <tj@kernel.org>

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/media/usb/ttusb-dec/ttusb_dec.c b/drivers/media/usb/ttusb-dec/ttusb_dec.c
index 79faa2560613..b4575fe89c95 100644
--- a/drivers/media/usb/ttusb-dec/ttusb_dec.c
+++ b/drivers/media/usb/ttusb-dec/ttusb_dec.c
@@ -19,6 +19,7 @@
 #include <linux/input.h>
 
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
 
 #include <media/dmxdev.h>
 #include <media/dvb_demux.h>
@@ -139,7 +140,7 @@ struct ttusb_dec {
 	int			v_pes_postbytes;
 
 	struct list_head	urb_frame_list;
-	struct tasklet_struct	urb_tasklet;
+	struct work_struct	urb_bh_work;
 	spinlock_t		urb_frame_list_lock;
 
 	struct dvb_demux_filter	*audio_filter;
@@ -766,9 +767,9 @@ static void ttusb_dec_process_urb_frame(struct ttusb_dec *dec, u8 *b,
 	}
 }
 
-static void ttusb_dec_process_urb_frame_list(struct tasklet_struct *t)
+static void ttusb_dec_process_urb_frame_list(struct work_struct *t)
 {
-	struct ttusb_dec *dec = from_tasklet(dec, t, urb_tasklet);
+	struct ttusb_dec *dec = from_work(dec, t, urb_bh_work);
 	struct list_head *item;
 	struct urb_frame *frame;
 	unsigned long flags;
@@ -822,7 +823,7 @@ static void ttusb_dec_process_urb(struct urb *urb)
 				spin_unlock_irqrestore(&dec->urb_frame_list_lock,
 						       flags);
 
-				tasklet_schedule(&dec->urb_tasklet);
+				queue_work(system_bh_wq, &dec->urb_bh_work);
 			}
 		}
 	} else {
@@ -1198,11 +1199,11 @@ static int ttusb_dec_alloc_iso_urbs(struct ttusb_dec *dec)
 	return 0;
 }
 
-static void ttusb_dec_init_tasklet(struct ttusb_dec *dec)
+static void ttusb_dec_init_bh_work(struct ttusb_dec *dec)
 {
 	spin_lock_init(&dec->urb_frame_list_lock);
 	INIT_LIST_HEAD(&dec->urb_frame_list);
-	tasklet_setup(&dec->urb_tasklet, ttusb_dec_process_urb_frame_list);
+	INIT_WORK(&dec->urb_bh_work, ttusb_dec_process_urb_frame_list);
 }
 
 static int ttusb_init_rc( struct ttusb_dec *dec)
@@ -1588,12 +1589,12 @@ static void ttusb_dec_exit_usb(struct ttusb_dec *dec)
 	ttusb_dec_free_iso_urbs(dec);
 }
 
-static void ttusb_dec_exit_tasklet(struct ttusb_dec *dec)
+static void ttusb_dec_exit_bh_work(struct ttusb_dec *dec)
 {
 	struct list_head *item;
 	struct urb_frame *frame;
 
-	tasklet_kill(&dec->urb_tasklet);
+	cancel_work_sync(&dec->urb_bh_work);
 
 	while ((item = dec->urb_frame_list.next) != &dec->urb_frame_list) {
 		frame = list_entry(item, struct urb_frame, urb_frame_list);
@@ -1703,7 +1704,7 @@ static int ttusb_dec_probe(struct usb_interface *intf,
 
 	ttusb_dec_init_v_pes(dec);
 	ttusb_dec_init_filters(dec);
-	ttusb_dec_init_tasklet(dec);
+	ttusb_dec_init_bh_work(dec);
 
 	dec->active = 1;
 
@@ -1729,7 +1730,7 @@ static void ttusb_dec_disconnect(struct usb_interface *intf)
 	dprintk("%s\n", __func__);
 
 	if (dec->active) {
-		ttusb_dec_exit_tasklet(dec);
+		ttusb_dec_exit_bh_work(dec);
 		ttusb_dec_exit_filters(dec);
 		if(enable_rc)
 			ttusb_dec_exit_rc(dec);