[media] v4l: Allow changing control handler lock

Allow choosing the lock used by the control handler. This may be handy
sometimes when a driver providing multiple subdevs does not want to use
several locks to serialise its functions.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 20 insertions, 19 deletions

diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index edb2a6a066ca..e5531ace5ee7 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -1177,7 +1177,8 @@ static inline int handler_set_err(struct v4l2_ctrl_handler *hdl, int err)
 int v4l2_ctrl_handler_init(struct v4l2_ctrl_handler *hdl,
                            unsigned nr_of_controls_hint)
 {
-        mutex_init(&hdl->lock);
+        hdl->lock = &hdl->_lock;
+        mutex_init(hdl->lock);
         INIT_LIST_HEAD(&hdl->ctrls);
         INIT_LIST_HEAD(&hdl->ctrl_refs);
         hdl->nr_of_buckets = 1 + nr_of_controls_hint / 8;
@@ -1198,7 +1199,7 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
         if (hdl == NULL || hdl->buckets == NULL)
                 return;
 
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
         /* Free all nodes */
         list_for_each_entry_safe(ref, next_ref, &hdl->ctrl_refs, node) {
                 list_del(&ref->node);
@@ -1215,7 +1216,7 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
         hdl->buckets = NULL;
         hdl->cached = NULL;
         hdl->error = 0;
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
 }
 EXPORT_SYMBOL(v4l2_ctrl_handler_free);
 
@@ -1280,9 +1281,9 @@ static struct v4l2_ctrl_ref *find_ref_lock(
         struct v4l2_ctrl_ref *ref = NULL;
 
         if (hdl) {
-                mutex_lock(&hdl->lock);
+                mutex_lock(hdl->lock);
                 ref = find_ref(hdl, id);
-                mutex_unlock(&hdl->lock);
+                mutex_unlock(hdl->lock);
         }
         return ref;
 }
@@ -1329,7 +1330,7 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl,
 
         INIT_LIST_HEAD(&new_ref->node);
 
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
 
         /* Add immediately at the end of the list if the list is empty, or if
            the last element in the list has a lower ID.
@@ -1359,7 +1360,7 @@ insert_in_hash:
         hdl->buckets[bucket] = new_ref;
 
 unlock:
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
         return 0;
 }
 
@@ -1445,9 +1446,9 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl,
                 kfree(ctrl);
                 return NULL;
         }
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
         list_add_tail(&ctrl->node, &hdl->ctrls);
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
         return ctrl;
 }
 
@@ -1564,7 +1565,7 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
                 return 0;
         if (hdl->error)
                 return hdl->error;
-        mutex_lock(&add->lock);
+        mutex_lock(add->lock);
         list_for_each_entry(ref, &add->ctrl_refs, node) {
                 struct v4l2_ctrl *ctrl = ref->ctrl;
 
@@ -1578,7 +1579,7 @@ int v4l2_ctrl_add_handler(struct v4l2_ctrl_handler *hdl,
                 if (ret)
                         break;
         }
-        mutex_unlock(&add->lock);
+        mutex_unlock(add->lock);
         return ret;
 }
 EXPORT_SYMBOL(v4l2_ctrl_add_handler);
@@ -1742,11 +1743,11 @@ void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
         len = strlen(prefix);
         if (len && prefix[len - 1] != ' ')
                 colon = ": ";
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
         list_for_each_entry(ctrl, &hdl->ctrls, node)
                 if (!(ctrl->flags & V4L2_CTRL_FLAG_DISABLED))
                         log_ctrl(ctrl, prefix, colon);
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
 }
 EXPORT_SYMBOL(v4l2_ctrl_handler_log_status);
 
@@ -1758,7 +1759,7 @@ int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
 
         if (hdl == NULL)
                 return 0;
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
         list_for_each_entry(ctrl, &hdl->ctrls, node)
                 ctrl->done = false;
 
@@ -1783,7 +1784,7 @@ int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
                 if (ret)
                         break;
         }
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
         return ret;
 }
 EXPORT_SYMBOL(v4l2_ctrl_handler_setup);
@@ -1798,7 +1799,7 @@ int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc)
         if (hdl == NULL)
                 return -EINVAL;
 
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
 
         /* Try to find it */
         ref = find_ref(hdl, id);
@@ -1823,7 +1824,7 @@ int v4l2_queryctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_queryctrl *qc)
                                         break;
                 }
         }
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
         if (!ref)
                 return -EINVAL;
 
@@ -2000,7 +2001,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
            belong to the same cluster. */
 
         /* This has to be done with the handler lock taken. */
-        mutex_lock(&hdl->lock);
+        mutex_lock(hdl->lock);
 
         /* First zero the helper field in the master control references */
         for (i = 0; i < cs->count; i++)
@@ -2022,7 +2023,7 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
                 /* Point the mref helper to the current helper struct. */
                 mref->helper = h;
         }
-        mutex_unlock(&hdl->lock);
+        mutex_unlock(hdl->lock);
         return 0;
 }