[PATCH v2] videobuf2: Add missing lock held on vb2_fop_relase
From: sylvester.nawrocki@gmail.com (Sylwester Nawrocki)
Date: 2013-10-19 18:27:10
Also in:
linux-media, linux-samsung-soc, lkml
On 10/19/2013 06:07 PM, Ricardo Ribalda wrote: [...]
quoted hunk ↗ jump to hunk
--- 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.
quoted hunk ↗ jump to hunk
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);
quoted hunk ↗ jump to hunk
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