media: ivsc: csi: add separate lock for v4l2 control handler

There're possibilities that privacy status change notification happens
in the middle of the ongoing mei command which already takes the command
lock, but v4l2_ctrl_s_ctrl() would also need the same lock prior to this
patch, so this may results in circular locking problem. This patch adds
one dedicated lock for v4l2 control handler to avoid described issue.

Fixes: 29006e196a56 ("media: pci: intel: ivsc: Add CSI submodule")
Cc: stable@vger.kernel.org # for 6.6 and later
Reported-by: Hao Yao <hao.yao@intel.com>
Signed-off-by: Wentong Wu <wentong.wu@intel.com>
Tested-by: Jason Chen <jason.z.chen@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/pci/intel/ivsc/mei_csi.c b/drivers/media/pci/intel/ivsc/mei_csi.c
index f04a89584334bfefdbc321194913978e94310663..c6d8f72e4eec597a6ca44d87366498e96c5f311a 100644 (file)
--- a/drivers/media/pci/intel/ivsc/mei_csi.c
+++ b/drivers/media/pci/intel/ivsc/mei_csi.c
@@ -126,6 +126,8 @@ struct mei_csi {
        struct v4l2_ctrl_handler ctrl_handler;
        struct v4l2_ctrl *freq_ctrl;
        struct v4l2_ctrl *privacy_ctrl;
+       /* lock for v4l2 controls */
+       struct mutex ctrl_lock;
        unsigned int remote_pad;
        /* start streaming or not */
        int streaming;
@@ -559,11 +561,13 @@ static int mei_csi_init_controls(struct mei_csi *csi)
        u32 max;
        int ret;
 
+       mutex_init(&csi->ctrl_lock);
+
        ret = v4l2_ctrl_handler_init(&csi->ctrl_handler, 2);
        if (ret)
                return ret;
 
-       csi->ctrl_handler.lock = &csi->lock;
+       csi->ctrl_handler.lock = &csi->ctrl_lock;
 
        max = ARRAY_SIZE(link_freq_menu_items) - 1;
        csi->freq_ctrl = v4l2_ctrl_new_int_menu(&csi->ctrl_handler,
@@ -755,6 +759,7 @@ err_entity:
 
 err_ctrl_handler:
        v4l2_ctrl_handler_free(&csi->ctrl_handler);
+       mutex_destroy(&csi->ctrl_lock);
        v4l2_async_nf_unregister(&csi->notifier);
        v4l2_async_nf_cleanup(&csi->notifier);
 
@@ -774,6 +779,7 @@ static void mei_csi_remove(struct mei_cl_device *cldev)
        v4l2_async_nf_unregister(&csi->notifier);
        v4l2_async_nf_cleanup(&csi->notifier);
        v4l2_ctrl_handler_free(&csi->ctrl_handler);
+       mutex_destroy(&csi->ctrl_lock);
        v4l2_async_unregister_subdev(&csi->subdev);
        v4l2_subdev_cleanup(&csi->subdev);
        media_entity_cleanup(&csi->subdev.entity);