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| author | Hans Verkuil <hans.verkuil@cisco.com> | 2012-05-14 16:28:44 +0200 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-05-14 20:06:25 +0200 |
| commit | 47bd4bc1a2624939c9f4ba154a2c18abe9d6c614 (patch) | |
| tree | 7fe3b434161fef4305db7b508d7edd294c981140 /include/media/v4l2-dev.h | |
| parent | [media] v4l2-framework.txt: update the core lock documentation (diff) | |
| download | linux-47bd4bc1a2624939c9f4ba154a2c18abe9d6c614.tar.xz linux-47bd4bc1a2624939c9f4ba154a2c18abe9d6c614.zip | |
[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>
Diffstat (limited to 'include/media/v4l2-dev.h')
| -rw-r--r-- | include/media/v4l2-dev.h | 2 |
1 files changed, 1 insertions, 1 deletions
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 */ |