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authorHans Verkuil <hans.verkuil@cisco.com>2012-05-14 11:28:44 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-05-14 15:06:25 -0300
commit47bd4bc1a2624939c9f4ba154a2c18abe9d6c614 (patch)
tree7fe3b434161fef4305db7b508d7edd294c981140
parent74f22c48640cf39df1f9cbf4fac07f5fcd365a48 (diff)
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op-kernel-dev-47bd4bc1a2624939c9f4ba154a2c18abe9d6c614.tar.gz
[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 <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
-rw-r--r--include/media/v4l2-dev.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index b604a7a..70d91c9 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 */
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