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>

5 files changed, 22 insertions, 20 deletions

diff --git a/drivers/media/platform/intel/pxa_camera.c b/drivers/media/platform/intel/pxa_camera.c
index d904952bf00e..f118aaac0b38 100644
--- a/drivers/media/platform/intel/pxa_camera.c
+++ b/drivers/media/platform/intel/pxa_camera.c
@@ -43,6 +43,7 @@
 #include <linux/videodev2.h>
 
 #include <linux/platform_data/media/camera-pxa.h>
+#include <linux/workqueue.h>
 
 #define PXA_CAM_VERSION "0.0.6"
 #define PXA_CAM_DRV_NAME "pxa27x-camera"
@@ -683,7 +684,7 @@ struct pxa_camera_dev {
 	unsigned int		buf_sequence;
 
 	struct pxa_buffer	*active;
-	struct tasklet_struct	task_eof;
+	struct work_struct	eof_bh_work;
 
 	u32			save_cicr[5];
 };
@@ -1146,9 +1147,9 @@ static void pxa_camera_deactivate(struct pxa_camera_dev *pcdev)
 	clk_disable_unprepare(pcdev->clk);
 }
 
-static void pxa_camera_eof(struct tasklet_struct *t)
+static void pxa_camera_eof_bh_work(struct work_struct *t)
 {
-	struct pxa_camera_dev *pcdev = from_tasklet(pcdev, t, task_eof);
+	struct pxa_camera_dev *pcdev = from_work(pcdev, t, eof_bh_work);
 	unsigned long cifr;
 	struct pxa_buffer *buf;
 
@@ -1185,7 +1186,7 @@ static irqreturn_t pxa_camera_irq(int irq, void *data)
 	if (status & CISR_EOF) {
 		cicr0 = __raw_readl(pcdev->base + CICR0) | CICR0_EOFM;
 		__raw_writel(cicr0, pcdev->base + CICR0);
-		tasklet_schedule(&pcdev->task_eof);
+		queue_work(system_bh_wq, &pcdev->eof_bh_work);
 	}
 
 	return IRQ_HANDLED;
@@ -2383,7 +2384,7 @@ static int pxa_camera_probe(struct platform_device *pdev)
 		}
 	}
 
-	tasklet_setup(&pcdev->task_eof, pxa_camera_eof);
+	INIT_WORK(&pcdev->eof_bh_work, pxa_camera_eof_bh_work);
 
 	pxa_camera_activate(pcdev);
 
@@ -2409,7 +2410,7 @@ static int pxa_camera_probe(struct platform_device *pdev)
 	return 0;
 exit_deactivate:
 	pxa_camera_deactivate(pcdev);
-	tasklet_kill(&pcdev->task_eof);
+	cancel_work_sync(&pcdev->eof_bh_work);
 exit_free_dma:
 	dma_release_channel(pcdev->dma_chans[2]);
 exit_free_dma_u:
@@ -2428,7 +2429,7 @@ static void pxa_camera_remove(struct platform_device *pdev)
 	struct pxa_camera_dev *pcdev = platform_get_drvdata(pdev);
 
 	pxa_camera_deactivate(pcdev);
-	tasklet_kill(&pcdev->task_eof);
+	cancel_work_sync(&pcdev->eof_bh_work);
 	dma_release_channel(pcdev->dma_chans[0]);
 	dma_release_channel(pcdev->dma_chans[1]);
 	dma_release_channel(pcdev->dma_chans[2]);
diff --git a/drivers/media/platform/marvell/mcam-core.c b/drivers/media/platform/marvell/mcam-core.c
index 9dfaea56a46d..c81593c969e0 100644
--- a/drivers/media/platform/marvell/mcam-core.c
+++ b/drivers/media/platform/marvell/mcam-core.c
@@ -439,9 +439,9 @@ static void mcam_ctlr_dma_vmalloc(struct mcam_camera *cam)
 /*
  * Copy data out to user space in the vmalloc case
  */
-static void mcam_frame_tasklet(struct tasklet_struct *t)
+static void mcam_frame_work(struct work_struct *t)
 {
-	struct mcam_camera *cam = from_tasklet(cam, t, s_tasklet);
+	struct mcam_camera *cam = from_work(cam, t, s_bh_work);
 	int i;
 	unsigned long flags;
 	struct mcam_vb_buffer *buf;
@@ -493,7 +493,7 @@ static int mcam_check_dma_buffers(struct mcam_camera *cam)
 
 static void mcam_vmalloc_done(struct mcam_camera *cam, int frame)
 {
-	tasklet_schedule(&cam->s_tasklet);
+	queue_work(system_bh_wq, &cam->s_bh_work);
 }
 
 #else /* MCAM_MODE_VMALLOC */
@@ -1305,7 +1305,7 @@ static int mcam_setup_vb2(struct mcam_camera *cam)
 		break;
 	case B_vmalloc:
 #ifdef MCAM_MODE_VMALLOC
-		tasklet_setup(&cam->s_tasklet, mcam_frame_tasklet);
+		INIT_WORK(&cam->s_bh_work, mcam_frame_work);
 		vq->ops = &mcam_vb2_ops;
 		vq->mem_ops = &vb2_vmalloc_memops;
 		cam->dma_setup = mcam_ctlr_dma_vmalloc;
diff --git a/drivers/media/platform/marvell/mcam-core.h b/drivers/media/platform/marvell/mcam-core.h
index 51e66db45af6..989dc6859a53 100644
--- a/drivers/media/platform/marvell/mcam-core.h
+++ b/drivers/media/platform/marvell/mcam-core.h
@@ -9,6 +9,7 @@
 
 #include <linux/list.h>
 #include <linux/clk-provider.h>
+#include <linux/workqueue.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-dev.h>
@@ -167,7 +168,7 @@ struct mcam_camera {
 	unsigned int dma_buf_size;	/* allocated size */
 	void *dma_bufs[MAX_DMA_BUFS];	/* Internal buffer addresses */
 	dma_addr_t dma_handles[MAX_DMA_BUFS]; /* Buffer bus addresses */
-	struct tasklet_struct s_tasklet;
+	struct work_struct s_bh_work;
 #endif
 	unsigned int sequence;		/* Frame sequence number */
 	unsigned int buf_seq[MAX_DMA_BUFS]; /* Sequence for individual bufs */
diff --git a/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.c b/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.c
index 2f58a0d0df85..67d3d6e50d2e 100644
--- a/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.c
+++ b/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.c
@@ -72,16 +72,16 @@ static void c8sectpfe_timer_interrupt(struct timer_list *t)
 
 		/* is this descriptor initialised and TP enabled */
 		if (channel->irec && readl(channel->irec + DMA_PRDS_TPENABLE))
-			tasklet_schedule(&channel->tsklet);
+			queue_work(system_bh_wq, &channel->bh_work);
 	}
 
 	fei->timer.expires = jiffies +	msecs_to_jiffies(POLL_MSECS);
 	add_timer(&fei->timer);
 }
 
-static void channel_swdemux_tsklet(struct tasklet_struct *t)
+static void channel_swdemux_bh_work(struct work_struct *t)
 {
-	struct channel_info *channel = from_tasklet(channel, t, tsklet);
+	struct channel_info *channel = from_work(channel, t, bh_work);
 	struct c8sectpfei *fei;
 	unsigned long wp, rp;
 	int pos, num_packets, n, size;
@@ -210,7 +210,7 @@ static int c8sectpfe_start_feed(struct dvb_demux_feed *dvbdmxfeed)
 
 		dev_dbg(fei->dev, "Starting channel=%p\n", channel);
 
-		tasklet_setup(&channel->tsklet, channel_swdemux_tsklet);
+		INIT_WORK(&channel->bh_work, channel_swdemux_bh_work);
 
 		/* Reset the internal inputblock sram pointers */
 		writel(channel->fifo,
@@ -303,7 +303,7 @@ static int c8sectpfe_stop_feed(struct dvb_demux_feed *dvbdmxfeed)
 		/* disable this channels descriptor */
 		writel(0,  channel->irec + DMA_PRDS_TPENABLE);
 
-		tasklet_disable(&channel->tsklet);
+		disable_work_sync(&channel->bh_work);
 
 		/* now request memdma channel goes idle */
 		idlereq = (1 << channel->tsin_id) | IDLEREQ;
@@ -630,8 +630,8 @@ static int configure_memdma_and_inputblock(struct c8sectpfei *fei,
 	writel(tsin->back_buffer_busaddr, tsin->irec + DMA_PRDS_BUSWP_TP(0));
 	writel(tsin->back_buffer_busaddr, tsin->irec + DMA_PRDS_BUSRP_TP(0));
 
-	/* initialize tasklet */
-	tasklet_setup(&tsin->tsklet, channel_swdemux_tsklet);
+	/* initialize bh work */
+	INIT_WORK(&tsin->bh_work, channel_swdemux_bh_work);
 
 	return 0;
 
diff --git a/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.h b/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.h
index bf377cc82225..c1b124c6ef12 100644
--- a/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.h
+++ b/drivers/media/platform/st/sti/c8sectpfe/c8sectpfe-core.h
@@ -51,7 +51,7 @@ struct channel_info {
 	unsigned long  fifo;
 
 	struct completion idle_completion;
-	struct tasklet_struct tsklet;
+	struct work_struct bh_work;
 
 	struct c8sectpfei *fei;
 	void __iomem *irec;