On 10 September 2012 17:29, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> 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 <p.zabel@xxxxxxxxxxxxxx>
> ---
> 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 mutex dev_mutex;
> struct v4l2_m2m_dev *m2m_dev;
> struct vb2_alloc_ctx *alloc_ctx;
> - int instances;
> + struct list_head instances;
> + unsigned long instance_mask;
> };
>
> struct coda_params {
> @@ -152,6 +153,7 @@ struct coda_params {
>
> struct coda_ctx {
> struct coda_dev *dev;
> + struct list_head list;
> 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 <javier.martin@xxxxxxxxxxxxxxxxx
--
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60
www.vista-silicon.com
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
