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>

2 files changed, 14 insertions, 13 deletions

diff --git a/drivers/media/pci/ngene/ngene-core.c b/drivers/media/pci/ngene/ngene-core.c
index 24ec576dc3bf..db6796240bce 100644
--- a/drivers/media/pci/ngene/ngene-core.c
+++ b/drivers/media/pci/ngene/ngene-core.c
@@ -50,9 +50,9 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 /* nGene interrupt handler **************************************************/
 /****************************************************************************/
 
-static void event_tasklet(struct tasklet_struct *t)
+static void event_bh_work(struct work_struct *t)
 {
-	struct ngene *dev = from_tasklet(dev, t, event_tasklet);
+	struct ngene *dev = from_work(dev, t, event_bh_work);
 
 	while (dev->EventQueueReadIndex != dev->EventQueueWriteIndex) {
 		struct EVENT_BUFFER Event =
@@ -68,9 +68,9 @@ static void event_tasklet(struct tasklet_struct *t)
 	}
 }
 
-static void demux_tasklet(struct tasklet_struct *t)
+static void demux_bh_work(struct work_struct *t)
 {
-	struct ngene_channel *chan = from_tasklet(chan, t, demux_tasklet);
+	struct ngene_channel *chan = from_work(chan, t, demux_bh_work);
 	struct device *pdev = &chan->dev->pci_dev->dev;
 	struct SBufferHeader *Cur = chan->nextBuffer;
 
@@ -204,7 +204,7 @@ static irqreturn_t irq_handler(int irq, void *dev_id)
 			dev->EventQueueOverflowFlag = 1;
 		}
 		dev->EventBuffer->EventStatus &= ~0x80;
-		tasklet_schedule(&dev->event_tasklet);
+		queue_work(system_bh_wq, &dev->event_bh_work);
 		rc = IRQ_HANDLED;
 	}
 
@@ -217,8 +217,8 @@ static irqreturn_t irq_handler(int irq, void *dev_id)
 			     ngeneBuffer.SR.Flags & 0xC0) == 0x80) {
 				dev->channel[i].nextBuffer->
 					ngeneBuffer.SR.Flags |= 0x40;
-				tasklet_schedule(
-					&dev->channel[i].demux_tasklet);
+				queue_work(system_bh_wq,
+					   &dev->channel[i].demux_bh_work);
 				rc = IRQ_HANDLED;
 			}
 		}
@@ -1181,7 +1181,7 @@ static void ngene_init(struct ngene *dev)
 	struct device *pdev = &dev->pci_dev->dev;
 	int i;
 
-	tasklet_setup(&dev->event_tasklet, event_tasklet);
+	INIT_WORK(&dev->event_bh_work, event_bh_work);
 
 	memset_io(dev->iomem + 0xc000, 0x00, 0x220);
 	memset_io(dev->iomem + 0xc400, 0x00, 0x100);
@@ -1395,7 +1395,7 @@ static void release_channel(struct ngene_channel *chan)
 	if (chan->running)
 		set_transfer(chan, 0);
 
-	tasklet_kill(&chan->demux_tasklet);
+	cancel_work_sync(&chan->demux_bh_work);
 
 	if (chan->ci_dev) {
 		dvb_unregister_device(chan->ci_dev);
@@ -1445,7 +1445,7 @@ static int init_channel(struct ngene_channel *chan)
 	struct ngene_info *ni = dev->card_info;
 	int io = ni->io_type[nr];
 
-	tasklet_setup(&chan->demux_tasklet, demux_tasklet);
+	INIT_WORK(&chan->demux_bh_work, demux_bh_work);
 	chan->users = 0;
 	chan->type = io;
 	chan->mode = chan->type;	/* for now only one mode */
@@ -1649,7 +1649,7 @@ void ngene_remove(struct pci_dev *pdev)
 	struct ngene *dev = pci_get_drvdata(pdev);
 	int i;
 
-	tasklet_kill(&dev->event_tasklet);
+	cancel_work_sync(&dev->event_bh_work);
 	for (i = MAX_STREAM - 1; i >= 0; i--)
 		release_channel(&dev->channel[i]);
 	if (dev->ci.en)
diff --git a/drivers/media/pci/ngene/ngene.h b/drivers/media/pci/ngene/ngene.h
index d1d7da84cd9d..9f989420b9e7 100644
--- a/drivers/media/pci/ngene/ngene.h
+++ b/drivers/media/pci/ngene/ngene.h
@@ -16,6 +16,7 @@
 #include <linux/scatterlist.h>
 
 #include <linux/dvb/frontend.h>
+#include <linux/workqueue.h>
 
 #include <media/dmxdev.h>
 #include <media/dvbdev.h>
@@ -621,7 +622,7 @@ struct ngene_channel {
 	int                   users;
 	struct video_device  *v4l_dev;
 	struct dvb_device    *ci_dev;
-	struct tasklet_struct demux_tasklet;
+	struct work_struct    demux_bh_work;
 
 	struct SBufferHeader *nextBuffer;
 	enum KSSTATE          State;
@@ -717,7 +718,7 @@ struct ngene {
 	struct EVENT_BUFFER   EventQueue[EVENT_QUEUE_SIZE];
 	int                   EventQueueOverflowCount;
 	int                   EventQueueOverflowFlag;
-	struct tasklet_struct event_tasklet;
+	struct work_struct    event_bh_work;
 	struct EVENT_BUFFER  *EventBuffer;
 	int                   EventQueueWriteIndex;
 	int                   EventQueueReadIndex;