[media] em28xx: remove V4L2_FL_LOCK_ALL_FOPS

Add proper locking to the file operations, allowing for the removal
of the V4L2_FL_LOCK_ALL_FOPS flag.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 35 insertions, 17 deletions

diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index 50f5f4fc2148..ecb23df7f16e 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -2146,9 +2146,12 @@ static int em28xx_v4l2_open(struct file *filp)
                         dev->users);
 
 
+        if (mutex_lock_interruptible(&dev->lock))
+                return -ERESTARTSYS;
         fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL);
         if (!fh) {
                 em28xx_errdev("em28xx-video.c: Out of memory?!\n");
+                mutex_unlock(&dev->lock);
                 return -ENOMEM;
         }
         fh->dev = dev;
@@ -2189,6 +2192,7 @@ static int em28xx_v4l2_open(struct file *filp)
                                     V4L2_BUF_TYPE_VBI_CAPTURE,
                                     V4L2_FIELD_SEQ_TB,
                                     sizeof(struct em28xx_buffer), fh, &dev->lock);
+        mutex_unlock(&dev->lock);
 
         return errCode;
 }
@@ -2243,6 +2247,7 @@ static int em28xx_v4l2_close(struct file *filp)
 
         em28xx_videodbg("users=%d\n", dev->users);
 
+        mutex_lock(&dev->lock);
         if (res_check(fh, EM28XX_RESOURCE_VIDEO)) {
                 videobuf_stop(&fh->vb_vidq);
                 res_free(fh, EM28XX_RESOURCE_VIDEO);
@@ -2261,6 +2266,7 @@ static int em28xx_v4l2_close(struct file *filp)
                         kfree(dev->alt_max_pkt_size);
                         kfree(dev);
                         kfree(fh);
+                        mutex_unlock(&dev->lock);
                         return 0;
                 }
 
@@ -2285,6 +2291,7 @@ static int em28xx_v4l2_close(struct file *filp)
         videobuf_mmap_free(&fh->vb_vbiq);
         kfree(fh);
         dev->users--;
+        mutex_unlock(&dev->lock);
         return 0;
 }
 
@@ -2304,35 +2311,35 @@ em28xx_v4l2_read(struct file *filp, char __user *buf, size_t count,
         if (rc < 0)
                 return rc;
 
+        if (mutex_lock_interruptible(&dev->lock))
+                return -ERESTARTSYS;
         /* FIXME: read() is not prepared to allow changing the video
            resolution while streaming. Seems a bug at em28xx_set_fmt
          */
 
         if (fh->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
                 if (res_locked(dev, EM28XX_RESOURCE_VIDEO))
-                        return -EBUSY;
-
-                return videobuf_read_stream(&fh->vb_vidq, buf, count, pos, 0,
+                        rc = -EBUSY;
+                else
+                        rc = videobuf_read_stream(&fh->vb_vidq, buf, count, pos, 0,
                                         filp->f_flags & O_NONBLOCK);
-        }
-
-
-        if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
+        } else if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
                 if (!res_get(fh, EM28XX_RESOURCE_VBI))
-                        return -EBUSY;
-
-                return videobuf_read_stream(&fh->vb_vbiq, buf, count, pos, 0,
+                        rc = -EBUSY;
+                else
+                        rc = videobuf_read_stream(&fh->vb_vbiq, buf, count, pos, 0,
                                         filp->f_flags & O_NONBLOCK);
         }
+        mutex_unlock(&dev->lock);
 
-        return 0;
+        return rc;
 }
 
 /*
- * em28xx_v4l2_poll()
+ * em28xx_poll()
  * will allocate buffers when called for the first time
  */
-static unsigned int em28xx_v4l2_poll(struct file *filp, poll_table *wait)
+static unsigned int em28xx_poll(struct file *filp, poll_table *wait)
 {
         struct em28xx_fh *fh = filp->private_data;
         struct em28xx *dev = fh->dev;
@@ -2355,6 +2362,18 @@ static unsigned int em28xx_v4l2_poll(struct file *filp, poll_table *wait)
         }
 }
 
+static unsigned int em28xx_v4l2_poll(struct file *filp, poll_table *wait)
+{
+        struct em28xx_fh *fh = filp->private_data;
+        struct em28xx *dev = fh->dev;
+        unsigned int res;
+
+        mutex_lock(&dev->lock);
+        res = em28xx_poll(filp, wait);
+        mutex_unlock(&dev->lock);
+        return res;
+}
+
 /*
  * em28xx_v4l2_mmap()
  */
@@ -2368,10 +2387,13 @@ static int em28xx_v4l2_mmap(struct file *filp, struct vm_area_struct *vma)
         if (rc < 0)
                 return rc;
 
+        if (mutex_lock_interruptible(&dev->lock))
+                return -ERESTARTSYS;
         if (fh->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                 rc = videobuf_mmap_mapper(&fh->vb_vidq, vma);
         else if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE)
                 rc = videobuf_mmap_mapper(&fh->vb_vbiq, vma);
+        mutex_unlock(&dev->lock);
 
         em28xx_videodbg("vma start=0x%08lx, size=%ld, ret=%d\n",
                 (unsigned long)vma->vm_start,
@@ -2495,10 +2517,6 @@ static struct video_device *em28xx_vdev_init(struct em28xx *dev,
         vfd->release    = video_device_release;
         vfd->debug      = video_debug;
         vfd->lock       = &dev->lock;
-        /* Locking in file operations other than ioctl should be done
-           by the driver, not the V4L2 core.
-           This driver needs auditing so that this flag can be removed. */
-        set_bit(V4L2_FL_LOCK_ALL_FOPS, &vfd->flags);
 
         snprintf(vfd->name, sizeof(vfd->name), "%s %s",
                  dev->name, type_name);