From: Hans Verkuil Date: Mon, 14 May 2012 14:28:44 +0000 (-0300) Subject: [media] v4l2-dev.h: add comment not to use V4L2_FL_LOCK_ALL_FOPS in new drivers X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=47bd4bc1a2624939c9f4ba154a2c18abe9d6c614;p=openwrt%2Fstaging%2Fblogic.git [media] v4l2-dev.h: add comment not to use V4L2_FL_LOCK_ALL_FOPS in new drivers This flag is for legacy drivers only and will go away in the future. A note regarding commit 5126f2590bee412e3053de851cb07f531e4be36a (v4l2-dev: add flag to have the core lock all file operations): That commit message suggests that by not taking the core lock for fops other than unlocked_ioctl all problems relating to AB-BA locking and mm->mmap_sem are solved. This is not the case. More work needs to be done by moving the core lock further down into video_ioctl2. It should only be taken after the copy_from/to_user calls are done. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index b604a7a50940..70d91c99728b 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -40,7 +40,7 @@ struct v4l2_ctrl_handler; /* Use the prio field of v4l2_fh for core priority checking */ #define V4L2_FL_USE_FH_PRIO (2) /* If ioctl core locking is in use, then apply that also to all - file operations. */ + file operations. Don't use this flag in new drivers! */ #define V4L2_FL_LOCK_ALL_FOPS (3) /* Priority helper functions */