Re: [PATCH v4 06/16] media: coda: keep track of active instances
On 10 September 2012 17:29, Philipp Zabel wrote:
> Determining the next free instance just by incrementing and decrementing
> an instance counter does not work: if there are two instances opened,
> 0 and 1, and instance 0 is released, the next call to coda_open will
> create a new instance with index 1, but instance 1 is already in use.
>
> Instead, scan a bitfield of active instances to determine the first
> free instance index.
>
> Signed-off-by: Philipp Zabel
> ---
> drivers/media/platform/coda.c | 21 +
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/platform/coda.c b/drivers/media/platform/coda.c
> index d069787..159df08 100644
> --- a/drivers/media/platform/coda.c
> +++ b/drivers/media/platform/coda.c
> @@ -134,7 +134,8 @@ struct coda_dev {
> struct mutexdev_mutex;
> struct v4l2_m2m_dev *m2m_dev;
> struct vb2_alloc_ctx*alloc_ctx;
> - int instances;
> + struct list_headinstances;
> + unsigned long instance_mask;
> };
>
> struct coda_params {
> @@ -152,6 +153,7 @@ struct coda_params {
>
> struct coda_ctx {
> struct coda_dev *dev;
> + struct list_headlist;
> int aborting;
> int rawstreamon;
> int compstreamon;
> @@ -1357,14 +1359,22 @@ static int coda_queue_init(void *priv, struct
> vb2_queue *src_vq,
> return vb2_queue_init(dst_vq);
> }
>
> +static int coda_next_free_instance(struct coda_dev *dev)
> +{
> + return ffz(dev->instance_mask);
> +}
> +
> static int coda_open(struct file *file)
> {
> struct coda_dev *dev = video_drvdata(file);
> struct coda_ctx *ctx = NULL;
> int ret = 0;
> + int idx;
>
> - if (dev->instances >= CODA_MAX_INSTANCES)
> + idx = coda_next_free_instance(dev);
> + if (idx >= CODA_MAX_INSTANCES)
> return -EBUSY;
> + set_bit(idx, &dev->instance_mask);
>
> ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
> if (!ctx)
> @@ -1374,6 +1384,7 @@ static int coda_open(struct file *file)
> file->private_data = &ctx->fh;
> v4l2_fh_add(&ctx->fh);
> ctx->dev = dev;
> + ctx->idx = idx;
>
> set_default_params(ctx);
> ctx->m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx,
> @@ -1402,7 +1413,7 @@ static int coda_open(struct file *file)
> }
>
> coda_lock(ctx);
> - ctx->idx = dev->instances++;
> + list_add(&ctx->list, &dev->instances);
> coda_unlock(ctx);
>
> clk_prepare_enable(dev->clk_per);
> @@ -1429,7 +1440,7 @@ static int coda_release(struct file *file)
> ctx);
>
> coda_lock(ctx);
> - dev->instances--;
> + list_del(&ctx->list);
> coda_unlock(ctx);
>
> dma_free_coherent(&dev->plat_dev->dev, CODA_PARA_BUF_SIZE,
> @@ -1440,6 +1451,7 @@ static int coda_release(struct file *file)
> clk_disable_unprepare(dev->clk_ahb);
> v4l2_fh_del(&ctx->fh);
> v4l2_fh_exit(&ctx->fh);
> + clear_bit(ctx->idx, &dev->instance_mask);
> kfree(ctx);
>
> return 0;
> @@ -1822,6 +1834,7 @@ static int __devinit coda_probe(struct platform_device
> *pdev)
> }
>
> spin_lock_init(&dev->irqlock);
> + INIT_LIST_HEAD(&dev->instances);
>
> dev->plat_dev = pdev;
> dev->clk_per = devm_clk_get(&pdev->dev, "per");
> --
> 1.7.10.4
>
Tested-by: Javier Martin http://vger.kernel.org/majordomo-info.html
[PATCH v4 06/16] media: coda: keep track of active instances
Determining the next free instance just by incrementing and decrementing
an instance counter does not work: if there are two instances opened,
0 and 1, and instance 0 is released, the next call to coda_open will
create a new instance with index 1, but instance 1 is already in use.
Instead, scan a bitfield of active instances to determine the first
free instance index.
Signed-off-by: Philipp Zabel
---
drivers/media/platform/coda.c | 21 +
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/media/platform/coda.c b/drivers/media/platform/coda.c
index d069787..159df08 100644
--- a/drivers/media/platform/coda.c
+++ b/drivers/media/platform/coda.c
@@ -134,7 +134,8 @@ struct coda_dev {
struct mutexdev_mutex;
struct v4l2_m2m_dev *m2m_dev;
struct vb2_alloc_ctx*alloc_ctx;
- int instances;
+ struct list_headinstances;
+ unsigned long instance_mask;
};
struct coda_params {
@@ -152,6 +153,7 @@ struct coda_params {
struct coda_ctx {
struct coda_dev *dev;
+ struct list_headlist;
int aborting;
int rawstreamon;
int compstreamon;
@@ -1357,14 +1359,22 @@ static int coda_queue_init(void *priv, struct vb2_queue
*src_vq,
return vb2_queue_init(dst_vq);
}
+static int coda_next_free_instance(struct coda_dev *dev)
+{
+ return ffz(dev->instance_mask);
+}
+
static int coda_open(struct file *file)
{
struct coda_dev *dev = video_drvdata(file);
struct coda_ctx *ctx = NULL;
int ret = 0;
+ int idx;
- if (dev->instances >= CODA_MAX_INSTANCES)
+ idx = coda_next_free_instance(dev);
+ if (idx >= CODA_MAX_INSTANCES)
return -EBUSY;
+ set_bit(idx, &dev->instance_mask);
ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
if (!ctx)
@@ -1374,6 +1384,7 @@ static int coda_open(struct file *file)
file->private_data = &ctx->fh;
v4l2_fh_add(&ctx->fh);
ctx->dev = dev;
+ ctx->idx = idx;
set_default_params(ctx);
ctx->m2m_ctx = v4l2_m2m_ctx_init(dev->m2m_dev, ctx,
@@ -1402,7 +1413,7 @@ static int coda_open(struct file *file)
}
coda_lock(ctx);
- ctx->idx = dev->instances++;
+ list_add(&ctx->list, &dev->instances);
coda_unlock(ctx);
clk_prepare_enable(dev->clk_per);
@@ -1429,7 +1440,7 @@ static int coda_release(struct file *file)
ctx);
coda_lock(ctx);
- dev->instances--;
+ list_del(&ctx->list);
coda_unlock(ctx);
dma_free_coherent(&dev->plat_dev->dev, CODA_PARA_BUF_SIZE,
@@ -1440,6 +1451,7 @@ static int coda_release(struct file *file)
clk_disable_unprepare(dev->clk_ahb);
v4l2_fh_del(&ctx->fh);
v4l2_fh_exit(&ctx->fh);
+ clear_bit(ctx->idx, &dev->instance_mask);
kfree(ctx);
return 0;
@@ -1822,6 +1834,7 @@ static int __devinit coda_probe(struct platform_device
*pdev)
}
spin_lock_init(&dev->irqlock);
+ INIT_LIST_HEAD(&dev->instances);
dev->plat_dev = pdev;
dev->clk_per = devm_clk_get(&pdev->dev, "per");
--
1.7.10.4
--
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