[media] v4l2-dev/ioctl.c: add vb2_queue support to video_device

This prepares struct video_device for easier integration with vb2.

It also introduces a new lock that protects the vb2_queue. It is up
to the driver to use it or not. And the driver can associate an owner
filehandle with the queue to check whether queuing requests are
permitted for the calling filehandle.

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

5 files changed, 49 insertions, 19 deletions

diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index c2122e53f051..b82778174eef 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -348,20 +348,14 @@ static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
         int ret = -ENODEV;
 
         if (vdev->fops->unlocked_ioctl) {
-                bool locked = false;
+                struct mutex *lock = v4l2_ioctl_get_lock(vdev, cmd);
 
-                if (vdev->lock) {
-                        /* always lock unless the cmd is marked as "don't use lock" */
-                        locked = !v4l2_is_known_ioctl(cmd) ||
-                                 !test_bit(_IOC_NR(cmd), vdev->disable_locking);
-
-                        if (locked && mutex_lock_interruptible(vdev->lock))
-                                return -ERESTARTSYS;
-                }
+                if (lock && mutex_lock_interruptible(lock))
+                        return -ERESTARTSYS;
                 if (video_is_registered(vdev))
                         ret = vdev->fops->unlocked_ioctl(filp, cmd, arg);
-                if (locked)
-                        mutex_unlock(vdev->lock);
+                if (lock)
+                        mutex_unlock(lock);
         } else if (vdev->fops->ioctl) {
                 /* This code path is a replacement for the BKL. It is a major
                  * hack but it will have to do for those drivers that are not
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index fd6436edde70..70e0efb127a6 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -27,6 +27,7 @@
 #include <media/v4l2-event.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-chip-ident.h>
+#include <media/videobuf2-core.h>
 
 /* Zero out the end of the struct pointed to by p.  Everything after, but
  * not including, the specified field is cleared. */
@@ -1817,6 +1818,8 @@ struct v4l2_ioctl_info {
 #define INFO_FL_STD     (1 << 2)
 /* This is ioctl has its own function */
 #define INFO_FL_FUNC    (1 << 3)
+/* Queuing ioctl */
+#define INFO_FL_QUEUE   (1 << 4)
 /* Zero struct from after the field to the end */
 #define INFO_FL_CLEAR(v4l2_struct, field)                       \
         ((offsetof(struct v4l2_struct, field) +                 \
@@ -1846,15 +1849,15 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO_FNC(VIDIOC_ENUM_FMT, v4l_enum_fmt, v4l_print_fmtdesc, INFO_FL_CLEAR(v4l2_fmtdesc, type)),
         IOCTL_INFO_FNC(VIDIOC_G_FMT, v4l_g_fmt, v4l_print_format, INFO_FL_CLEAR(v4l2_format, type)),
         IOCTL_INFO_FNC(VIDIOC_S_FMT, v4l_s_fmt, v4l_print_format, INFO_FL_PRIO),
-        IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO),
-        IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_CLEAR(v4l2_buffer, length)),
+        IOCTL_INFO_FNC(VIDIOC_REQBUFS, v4l_reqbufs, v4l_print_requestbuffers, INFO_FL_PRIO | INFO_FL_QUEUE),
+        IOCTL_INFO_FNC(VIDIOC_QUERYBUF, v4l_querybuf, v4l_print_buffer, INFO_FL_QUEUE | INFO_FL_CLEAR(v4l2_buffer, length)),
         IOCTL_INFO_STD(VIDIOC_G_FBUF, vidioc_g_fbuf, v4l_print_framebuffer, 0),
         IOCTL_INFO_STD(VIDIOC_S_FBUF, vidioc_s_fbuf, v4l_print_framebuffer, INFO_FL_PRIO),
         IOCTL_INFO_STD(VIDIOC_OVERLAY, vidioc_overlay, v4l_print_u32, INFO_FL_PRIO),
-        IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, 0),
-        IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, 0),
-        IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO),
-        IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO),
+        IOCTL_INFO_FNC(VIDIOC_QBUF, v4l_qbuf, v4l_print_buffer, INFO_FL_QUEUE),
+        IOCTL_INFO_FNC(VIDIOC_DQBUF, v4l_dqbuf, v4l_print_buffer, INFO_FL_QUEUE),
+        IOCTL_INFO_FNC(VIDIOC_STREAMON, v4l_streamon, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
+        IOCTL_INFO_FNC(VIDIOC_STREAMOFF, v4l_streamoff, v4l_print_buftype, INFO_FL_PRIO | INFO_FL_QUEUE),
         IOCTL_INFO_FNC(VIDIOC_G_PARM, v4l_g_parm, v4l_print_streamparm, INFO_FL_CLEAR(v4l2_streamparm, type)),
         IOCTL_INFO_FNC(VIDIOC_S_PARM, v4l_s_parm, v4l_print_streamparm, INFO_FL_PRIO),
         IOCTL_INFO_FNC(VIDIOC_G_STD, v4l_g_std, v4l_print_std, 0),
@@ -1918,8 +1921,8 @@ static struct v4l2_ioctl_info v4l2_ioctls[] = {
         IOCTL_INFO_FNC(VIDIOC_DQEVENT, v4l_dqevent, v4l_print_event, 0),
         IOCTL_INFO_FNC(VIDIOC_SUBSCRIBE_EVENT, v4l_subscribe_event, v4l_print_event_subscription, 0),
         IOCTL_INFO_FNC(VIDIOC_UNSUBSCRIBE_EVENT, v4l_unsubscribe_event, v4l_print_event_subscription, 0),
-        IOCTL_INFO_FNC(VIDIOC_CREATE_BUFS, v4l_create_bufs, v4l_print_create_buffers, INFO_FL_PRIO),
-        IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF, v4l_prepare_buf, v4l_print_buffer, 0),
+        IOCTL_INFO_FNC(VIDIOC_CREATE_BUFS, v4l_create_bufs, v4l_print_create_buffers, INFO_FL_PRIO | INFO_FL_QUEUE),
+        IOCTL_INFO_FNC(VIDIOC_PREPARE_BUF, v4l_prepare_buf, v4l_print_buffer, INFO_FL_QUEUE),
         IOCTL_INFO_STD(VIDIOC_ENUM_DV_TIMINGS, vidioc_enum_dv_timings, v4l_print_enum_dv_timings, 0),
         IOCTL_INFO_STD(VIDIOC_QUERY_DV_TIMINGS, vidioc_query_dv_timings, v4l_print_dv_timings, 0),
         IOCTL_INFO_STD(VIDIOC_DV_TIMINGS_CAP, vidioc_dv_timings_cap, v4l_print_dv_timings_cap, 0),
@@ -1933,6 +1936,18 @@ bool v4l2_is_known_ioctl(unsigned int cmd)
         return v4l2_ioctls[_IOC_NR(cmd)].ioctl == cmd;
 }
 
+struct mutex *v4l2_ioctl_get_lock(struct video_device *vdev, unsigned cmd)
+{
+        if (_IOC_NR(cmd) >= V4L2_IOCTLS)
+                return vdev->lock;
+        if (test_bit(_IOC_NR(cmd), vdev->disable_locking))
+                return NULL;
+        if (vdev->queue && vdev->queue->lock &&
+                        (v4l2_ioctls[_IOC_NR(cmd)].flags & INFO_FL_QUEUE))
+                return vdev->queue->lock;
+        return vdev->lock;
+}
+
 /* Common ioctl debug function. This function can be used by
    external ioctl messages as well as internal V4L ioctl */
 void v4l_printk_ioctl(const char *prefix, unsigned int cmd)
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index a056e6ee1b68..5c416cdc88d5 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -100,6 +100,9 @@ struct video_device
         /* Control handler associated with this device node. May be NULL. */
         struct v4l2_ctrl_handler *ctrl_handler;
 
+        /* vb2_queue associated with this device node. May be NULL. */
+        struct vb2_queue *queue;
+
         /* Priority state. If NULL, then v4l2_dev->prio will be used. */
         struct v4l2_prio_state *prio;
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index dfd984f10d42..19e93523c2d8 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -304,6 +304,11 @@ extern int v4l2_video_std_construct(struct v4l2_standard *vs,
    then do printk(KERN_DEBUG "%s: ", prefix) first. */
 extern void v4l_printk_ioctl(const char *prefix, unsigned int cmd);
 
+/* Internal use only: get the mutex (if any) that we need to lock for the
+   given command. */
+struct video_device;
+extern struct mutex *v4l2_ioctl_get_lock(struct video_device *vdev, unsigned cmd);
+
 /* names for fancy debug output */
 extern const char *v4l2_field_names[];
 extern const char *v4l2_type_names[];
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index a15d1f1b319e..924e95e0a0a6 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -244,12 +244,23 @@ struct vb2_ops {
         void (*buf_queue)(struct vb2_buffer *vb);
 };
 
+struct v4l2_fh;
+
 /**
  * struct vb2_queue - a videobuf queue
  *
  * @type:       queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
  * @io_modes:   supported io methods (see vb2_io_modes enum)
  * @io_flags:   additional io flags (see vb2_fileio_flags enum)
+ * @lock:       pointer to a mutex that protects the vb2_queue struct. The
+ *              driver can set this to a mutex to let the v4l2 core serialize
+ *              the queuing ioctls. If the driver wants to handle locking
+ *              itself, then this should be set to NULL. This lock is not used
+ *              by the videobuf2 core API.
+ * @owner:      The filehandle that 'owns' the buffers, i.e. the filehandle
+ *              that called reqbufs, create_buffers or started fileio.
+ *              This field is not used by the videobuf2 core API, but it allows
+ *              drivers to easily associate an owner filehandle with the queue.
  * @ops:        driver-specific callbacks
  * @mem_ops:    memory allocator specific callbacks
  * @drv_priv:   driver private data
@@ -273,6 +284,8 @@ struct vb2_queue {
         enum v4l2_buf_type              type;
         unsigned int                    io_modes;
         unsigned int                    io_flags;
+        struct mutex                    *lock;
+        struct v4l2_fh                  *owner;
 
         const struct vb2_ops            *ops;
         const struct vb2_mem_ops        *mem_ops;