Messages in this thread Patch in this message | | | Date | Sat, 19 Oct 2013 20:27:02 +0200 | From | Sylwester Nawrocki <> | Subject | Re: [PATCH v2] videobuf2: Add missing lock held on vb2_fop_relase |
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On 10/19/2013 06:07 PM, Ricardo Ribalda wrote: [...] > --- > drivers/media/platform/exynos4-is/fimc-capture.c | 2 +- > drivers/media/platform/exynos4-is/fimc-lite.c | 2 +- > drivers/media/usb/em28xx/em28xx-video.c | 2 +- > drivers/media/v4l2-core/videobuf2-core.c | 18 +++++++++++++++++- > include/media/videobuf2-core.h | 2 ++ > 5 files changed, 22 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/platform/exynos4-is/fimc-capture.c b/drivers/media/platform/exynos4-is/fimc-capture.c > index fb27ff7..c38d247c 100644 > --- a/drivers/media/platform/exynos4-is/fimc-capture.c > +++ b/drivers/media/platform/exynos4-is/fimc-capture.c > @@ -549,7 +549,7 @@ static int fimc_capture_release(struct file *file) > vc->streaming = false; > } > > - ret = vb2_fop_release(file); > + ret = __vb2_fop_release(file, true); > > if (close) { > clear_bit(ST_CAPT_BUSY,&fimc->state); > diff --git a/drivers/media/platform/exynos4-is/fimc-lite.c b/drivers/media/platform/exynos4-is/fimc-lite.c > index e5798f7..021d804 100644 > --- a/drivers/media/platform/exynos4-is/fimc-lite.c > +++ b/drivers/media/platform/exynos4-is/fimc-lite.c > @@ -546,7 +546,7 @@ static int fimc_lite_release(struct file *file) > mutex_unlock(&entity->parent->graph_mutex); > } > > - vb2_fop_release(file); > + __vb2_fop_release(file, true); > pm_runtime_put(&fimc->pdev->dev); > clear_bit(ST_FLITE_SUSPENDED,&fimc->state); > > diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c > index 9d10334..6a5c147 100644 > --- a/drivers/media/usb/em28xx/em28xx-video.c > +++ b/drivers/media/usb/em28xx/em28xx-video.c > @@ -1664,7 +1664,7 @@ static int em28xx_v4l2_close(struct file *filp) > em28xx_videodbg("users=%d\n", dev->users); > > mutex_lock(&dev->lock); > - vb2_fop_release(filp); > + __vb2_fop_release(filp, false);
I believe no modifications are needed for this driver.
> if (dev->users == 1) { > /* the device is already disconnect, > diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c > index 594c75e..ce309a8 100644 > --- a/drivers/media/v4l2-core/videobuf2-core.c > +++ b/drivers/media/v4l2-core/videobuf2-core.c > @@ -2619,16 +2619,32 @@ int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma) > } > EXPORT_SYMBOL_GPL(vb2_fop_mmap); > > -int vb2_fop_release(struct file *file) > +int __vb2_fop_release(struct file *file, bool lock_is_held) > { > struct video_device *vdev = video_devdata(file); > + struct mutex *lock; > > if (file->private_data == vdev->queue->owner) { > + if (lock_is_held) > + lock = NULL; > + else > + lock = vdev->queue->lock ? > + vdev->queue->lock : vdev->lock; > + if (lock) > + mutex_lock(lock); > vb2_queue_release(vdev->queue); > vdev->queue->owner = NULL; > + if (lock) > + mutex_unlock(lock); > } > return v4l2_fh_release(file); > } > +EXPORT_SYMBOL_GPL(__vb2_fop_release); > + > +int vb2_fop_release(struct file *file) > +{ > + return __vb2_fop_release(file, false); > +} > EXPORT_SYMBOL_GPL(vb2_fop_release);
It might be better to make it something like:
static int _vb2_fop_release(struct file *file, bool locked) { struct video_device *vdev = video_devdata(file); struct mutex *lock;
if (file->private_data == vdev->queue->owner) { lock = vdev->queue->lock ? vdev->queue->lock : vdev->lock;
if (lock && !locked) mutex_lock(lock);
vb2_queue_release(vdev->queue); vdev->queue->owner = NULL; if (lock && !locked) mutex_unlock(lock); } return v4l2_fh_release(file); }
int vb2_fop_release(struct file *file) { return _vb2_fop_release(file, false); } EXPORT_SYMBOL_GPL(vb2_fop_release);
/* * This function should be used instead of vb2_fop_release() * if the caller already holds the video queue mutex. */ int __vb2_fop_release(struct file *file) { return _vb2_fop_release(file, true); } EXPORT_SYMBOL_GPL(__vb2_fop_release);
since __vb2_fop_release(file, false); is basically useless, it is same as vb2_fop_release(file);
> ssize_t vb2_fop_write(struct file *file, char __user *buf, > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > index 6781258..cd1e4d5 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -491,6 +491,8 @@ int vb2_ioctl_expbuf(struct file *file, void *priv, > > int vb2_fop_mmap(struct file *file, struct vm_area_struct *vma); > int vb2_fop_release(struct file *file); > +/* must be used if the lock is held. */
Let's put any comments at the function body, not here.
> +int __vb2_fop_release(struct file *file, bool lock_is_held);
int __vb2_fop_release(struct file *file);
> ssize_t vb2_fop_write(struct file *file, char __user *buf, > size_t count, loff_t *ppos); > ssize_t vb2_fop_read(struct file *file, char __user *buf,
Thanks, Sylwester
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