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>

3 files changed, 12 insertions, 10 deletions

diff --git a/drivers/media/pci/tw5864/tw5864-core.c b/drivers/media/pci/tw5864/tw5864-core.c
index 560ff1ddcc83..4d33caf83307 100644
--- a/drivers/media/pci/tw5864/tw5864-core.c
+++ b/drivers/media/pci/tw5864/tw5864-core.c
@@ -144,7 +144,7 @@ static void tw5864_h264_isr(struct tw5864_dev *dev)
 		cur_frame->gop_seqno = input->frame_gop_seqno;
 
 		dev->h264_buf_w_index = next_frame_index;
-		tasklet_schedule(&dev->tasklet);
+		queue_work(system_bh_wq, &dev->bh_work);
 
 		cur_frame = next_frame;
 
diff --git a/drivers/media/pci/tw5864/tw5864-video.c b/drivers/media/pci/tw5864/tw5864-video.c
index 8b1aae4b6319..4f35c159efe5 100644
--- a/drivers/media/pci/tw5864/tw5864-video.c
+++ b/drivers/media/pci/tw5864/tw5864-video.c
@@ -6,6 +6,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/workqueue.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-event.h>
 #include <media/videobuf2-dma-contig.h>
@@ -175,7 +176,7 @@ static const unsigned int intra4x4_lambda3[] = {
 static v4l2_std_id tw5864_get_v4l2_std(enum tw5864_vid_std std);
 static enum tw5864_vid_std tw5864_from_v4l2_std(v4l2_std_id v4l2_std);
 
-static void tw5864_handle_frame_task(struct tasklet_struct *t);
+static void tw5864_handle_frame_work(struct work_struct *t);
 static void tw5864_handle_frame(struct tw5864_h264_frame *frame);
 static void tw5864_frame_interval_set(struct tw5864_input *input);
 
@@ -1062,7 +1063,7 @@ int tw5864_video_init(struct tw5864_dev *dev, int *video_nr)
 	dev->irqmask |= TW5864_INTR_VLC_DONE | TW5864_INTR_TIMER;
 	tw5864_irqmask_apply(dev);
 
-	tasklet_setup(&dev->tasklet, tw5864_handle_frame_task);
+	INIT_WORK(&dev->bh_work, tw5864_handle_frame_work);
 
 	for (i = 0; i < TW5864_INPUTS; i++) {
 		dev->inputs[i].root = dev;
@@ -1079,7 +1080,7 @@ fini_video_inputs:
 	for (i = last_input_nr_registered; i >= 0; i--)
 		tw5864_video_input_fini(&dev->inputs[i]);
 
-	tasklet_kill(&dev->tasklet);
+	cancel_work_sync(&dev->bh_work);
 
 free_dma:
 	for (i = last_dma_allocated; i >= 0; i--) {
@@ -1198,7 +1199,7 @@ void tw5864_video_fini(struct tw5864_dev *dev)
 {
 	int i;
 
-	tasklet_kill(&dev->tasklet);
+	cancel_work_sync(&dev->bh_work);
 
 	for (i = 0; i < TW5864_INPUTS; i++)
 		tw5864_video_input_fini(&dev->inputs[i]);
@@ -1315,9 +1316,9 @@ static int tw5864_is_motion_triggered(struct tw5864_h264_frame *frame)
 	return detected;
 }
 
-static void tw5864_handle_frame_task(struct tasklet_struct *t)
+static void tw5864_handle_frame_work(struct work_struct *t)
 {
-	struct tw5864_dev *dev = from_tasklet(dev, t, tasklet);
+	struct tw5864_dev *dev = from_work(dev, t, bh_work);
 	unsigned long flags;
 	int batch_size = H264_BUF_CNT;
 
diff --git a/drivers/media/pci/tw5864/tw5864.h b/drivers/media/pci/tw5864/tw5864.h
index a8b6fbd5b710..2da5f4215fd9 100644
--- a/drivers/media/pci/tw5864/tw5864.h
+++ b/drivers/media/pci/tw5864/tw5864.h
@@ -12,6 +12,7 @@
 #include <linux/mutex.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
+#include <linux/workqueue.h>
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-ioctl.h>
@@ -85,7 +86,7 @@ struct tw5864_input {
 	int nr; /* input number */
 	struct tw5864_dev *root;
 	struct mutex lock; /* used for vidq and vdev */
-	spinlock_t slock; /* used for sync between ISR, tasklet & V4L2 API */
+	spinlock_t slock; /* used for sync between ISR, bh_work & V4L2 API */
 	struct video_device vdev;
 	struct v4l2_ctrl_handler hdl;
 	struct vb2_queue vidq;
@@ -142,7 +143,7 @@ struct tw5864_h264_frame {
 
 /* global device status */
 struct tw5864_dev {
-	spinlock_t slock; /* used for sync between ISR, tasklet & V4L2 API */
+	spinlock_t slock; /* used for sync between ISR, bh_work & V4L2 API */
 	struct v4l2_device v4l2_dev;
 	struct tw5864_input inputs[TW5864_INPUTS];
 #define H264_BUF_CNT 4
@@ -150,7 +151,7 @@ struct tw5864_dev {
 	int h264_buf_r_index;
 	int h264_buf_w_index;
 
-	struct tasklet_struct tasklet;
+	struct work_struct bh_work;
 
 	int encoder_busy;
 	/* Input number to check next for ready raw picture (in RR fashion) */