[media] uvcvideo: Lock stream mutex when accessing format-related information

The stream mutex protects access to the struct uvc_streaming ctrl,
cur_format and cur_frame fields as well as to the hardware probe
control. Lock it appropriately.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 58 insertions, 27 deletions

diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index 07dd2357fbb9..2f6dc6b97348 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -226,12 +226,14 @@ static int uvc_v4l2_try_format(struct uvc_streaming *stream,
          * developers test their webcams with the Linux driver as well as with
          * the Windows driver).
          */
+        mutex_lock(&stream->mutex);
         if (stream->dev->quirks & UVC_QUIRK_PROBE_EXTRAFIELDS)
                 probe->dwMaxVideoFrameSize =
                         stream->ctrl.dwMaxVideoFrameSize;
 
         /* Probe the device. */
         ret = uvc_probe_video(stream, probe);
+        mutex_unlock(&stream->mutex);
         if (ret < 0)
                 goto done;
 
@@ -255,14 +257,21 @@ done:
 static int uvc_v4l2_get_format(struct uvc_streaming *stream,
         struct v4l2_format *fmt)
 {
-        struct uvc_format *format = stream->cur_format;
-        struct uvc_frame *frame = stream->cur_frame;
+        struct uvc_format *format;
+        struct uvc_frame *frame;
+        int ret = 0;
 
         if (fmt->type != stream->type)
                 return -EINVAL;
 
-        if (format == NULL || frame == NULL)
-                return -EINVAL;
+        mutex_lock(&stream->mutex);
+        format = stream->cur_format;
+        frame = stream->cur_frame;
+
+        if (format == NULL || frame == NULL) {
+                ret = -EINVAL;
+                goto done;
+        }
 
         fmt->fmt.pix.pixelformat = format->fcc;
         fmt->fmt.pix.width = frame->wWidth;
@@ -273,7 +282,9 @@ static int uvc_v4l2_get_format(struct uvc_streaming *stream,
         fmt->fmt.pix.colorspace = format->colorspace;
         fmt->fmt.pix.priv = 0;
 
-        return 0;
+done:
+        mutex_unlock(&stream->mutex);
+        return ret;
 }
 
 static int uvc_v4l2_set_format(struct uvc_streaming *stream,
@@ -287,18 +298,24 @@ static int uvc_v4l2_set_format(struct uvc_streaming *stream,
         if (fmt->type != stream->type)
                 return -EINVAL;
 
-        if (uvc_queue_allocated(&stream->queue))
-                return -EBUSY;
-
         ret = uvc_v4l2_try_format(stream, fmt, &probe, &format, &frame);
         if (ret < 0)
                 return ret;
 
+        mutex_lock(&stream->mutex);
+
+        if (uvc_queue_allocated(&stream->queue)) {
+                ret = -EBUSY;
+                goto done;
+        }
+
         memcpy(&stream->ctrl, &probe, sizeof probe);
         stream->cur_format = format;
         stream->cur_frame = frame;
 
-        return 0;
+done:
+        mutex_unlock(&stream->mutex);
+        return ret;
 }
 
 static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
@@ -309,7 +326,10 @@ static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
         if (parm->type != stream->type)
                 return -EINVAL;
 
+        mutex_lock(&stream->mutex);
         numerator = stream->ctrl.dwFrameInterval;
+        mutex_unlock(&stream->mutex);
+
         denominator = 10000000;
         uvc_simplify_fraction(&numerator, &denominator, 8, 333);
 
@@ -336,7 +356,6 @@ static int uvc_v4l2_get_streamparm(struct uvc_streaming *stream,
 static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
                 struct v4l2_streamparm *parm)
 {
-        struct uvc_frame *frame = stream->cur_frame;
         struct uvc_streaming_control probe;
         struct v4l2_fract timeperframe;
         uint32_t interval;
@@ -345,28 +364,36 @@ static int uvc_v4l2_set_streamparm(struct uvc_streaming *stream,
         if (parm->type != stream->type)
                 return -EINVAL;
 
-        if (uvc_queue_streaming(&stream->queue))
-                return -EBUSY;
-
         if (parm->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
                 timeperframe = parm->parm.capture.timeperframe;
         else
                 timeperframe = parm->parm.output.timeperframe;
 
-        memcpy(&probe, &stream->ctrl, sizeof probe);
         interval = uvc_fraction_to_interval(timeperframe.numerator,
                 timeperframe.denominator);
-
         uvc_trace(UVC_TRACE_FORMAT, "Setting frame interval to %u/%u (%u).\n",
                 timeperframe.numerator, timeperframe.denominator, interval);
-        probe.dwFrameInterval = uvc_try_frame_interval(frame, interval);
+
+        mutex_lock(&stream->mutex);
+
+        if (uvc_queue_streaming(&stream->queue)) {
+                mutex_unlock(&stream->mutex);
+                return -EBUSY;
+        }
+
+        memcpy(&probe, &stream->ctrl, sizeof probe);
+        probe.dwFrameInterval =
+                uvc_try_frame_interval(stream->cur_frame, interval);
 
         /* Probe the device with the new settings. */
         ret = uvc_probe_video(stream, &probe);
-        if (ret < 0)
+        if (ret < 0) {
+                mutex_unlock(&stream->mutex);
                 return ret;
+        }
 
         memcpy(&stream->ctrl, &probe, sizeof probe);
+        mutex_unlock(&stream->mutex);
 
         /* Return the actual frame period. */
         timeperframe.numerator = probe.dwFrameInterval;
@@ -869,15 +896,17 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
         case VIDIOC_CROPCAP:
         {
                 struct v4l2_cropcap *ccap = arg;
-                struct uvc_frame *frame = stream->cur_frame;
 
                 if (ccap->type != stream->type)
                         return -EINVAL;
 
                 ccap->bounds.left = 0;
                 ccap->bounds.top = 0;
-                ccap->bounds.width = frame->wWidth;
-                ccap->bounds.height = frame->wHeight;
+
+                mutex_lock(&stream->mutex);
+                ccap->bounds.width = stream->cur_frame->wWidth;
+                ccap->bounds.height = stream->cur_frame->wHeight;
+                mutex_unlock(&stream->mutex);
 
                 ccap->defrect = ccap->bounds;
 
@@ -894,8 +923,6 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
         case VIDIOC_REQBUFS:
         {
                 struct v4l2_requestbuffers *rb = arg;
-                unsigned int bufsize =
-                        stream->ctrl.dwMaxVideoFrameSize;
 
                 if (rb->type != stream->type ||
                     rb->memory != V4L2_MEMORY_MMAP)
@@ -904,7 +931,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 if ((ret = uvc_acquire_privileges(handle)) < 0)
                         return ret;
 
-                ret = uvc_alloc_buffers(&stream->queue, rb->count, bufsize);
+                mutex_lock(&stream->mutex);
+                ret = uvc_alloc_buffers(&stream->queue, rb->count,
+                                        stream->ctrl.dwMaxVideoFrameSize);
+                mutex_unlock(&stream->mutex);
                 if (ret < 0)
                         return ret;
 
@@ -952,7 +982,9 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
                 if (!uvc_has_privileges(handle))
                         return -EBUSY;
 
+                mutex_lock(&stream->mutex);
                 ret = uvc_video_enable(stream, 1);
+                mutex_unlock(&stream->mutex);
                 if (ret < 0)
                         return ret;
                 break;
diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index 5555f0102838..5673d673504b 100644
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -293,8 +293,6 @@ int uvc_probe_video(struct uvc_streaming *stream,
         unsigned int i;
         int ret;
 
-        mutex_lock(&stream->mutex);
-
         /* Perform probing. The device should adjust the requested values
          * according to its capabilities. However, some devices, namely the
          * first generation UVC Logitech webcams, don't implement the Video
@@ -346,7 +344,6 @@ int uvc_probe_video(struct uvc_streaming *stream,
         }
 
 done:
-        mutex_unlock(&stream->mutex);
         return ret;
 }
 
diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h
index ea893bc0df07..45f01e7e13d2 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -436,7 +436,9 @@ struct uvc_streaming {
         struct uvc_streaming_control ctrl;
         struct uvc_format *cur_format;
         struct uvc_frame *cur_frame;
-
+        /* Protect access to ctrl, cur_format, cur_frame and hardware video
+         * probe control.
+         */
         struct mutex mutex;
 
         unsigned int frozen : 1;