Re: [PATCH] video4linux: Push down the BKL

!MAILaRCHIVE_VOTE_RePLACE
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To: Alan Cox <alan@...>
Cc: <video4linux-list@...>, <linux-kernel@...>, <mchehab@...>
Date: Friday, May 23, 2008 - 9:56 am

> diff --git a/drivers/media/video/cafe_ccic.c b/drivers/media/video/cafe_ccic.c

Weird, that was always intended to be that way, I'm not sure what
happened.  In any case, consider this part to be

	Acked-by: Jonathan Corbet <corbet@lwn.net>

However, in this part:



This forces the BKL on all V4L2 drivers whether or not they need it.
Given that this code can, in fact, be a path where latency matters
(consider VIDIOC_DQBUF), I'm not sure that's the best way to do it.

On the other hand, the next level of BKL pushdown would be painful as
all hell, given the massive number of callbacks in the V4L2 API.  So I'm
thinking it might be justified to create a video_ioctl2_locked() for
V4L2 drivers which are not yet known to be safe in the absence of the
BKL.  The amount of extra code would be quite small, and it would let
safe drivers operate BKL-free.

jon
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Messages in current thread:
[PATCH] video4linux: Push down the BKL, Alan Cox, (Thu May 22, 5:37 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Mon May 26, 12:59 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Mon May 26, 4:23 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Mon May 26, 5:10 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Mon May 26, 6:01 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Tue May 27, 9:10 am)
Re: [PATCH] video4linux: Push down the BKL, Jonathan Corbet, (Tue May 27, 11:41 am)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Tue May 27, 12:31 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Tue May 27, 2:14 pm)
Re: [PATCH] video4linux: Push down the BKL, Jonathan Corbet, (Tue May 27, 12:37 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Tue May 27, 2:59 pm)
Re: [PATCH] video4linux: Push down the BKL, Arjan van de Ven, (Tue May 27, 3:50 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Tue May 27, 4:24 pm)
Re: [PATCH] video4linux: Push down the BKL, Devin Heitmueller, (Tue May 27, 3:26 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Tue May 27, 5:00 pm)
Re: [PATCH] video4linux: Push down the BKL, Andy Walls, (Tue May 27, 7:48 pm)
Re: [PATCH] video4linux: Push down the BKL, Devin Heitmueller, (Tue May 27, 8:46 pm)
Re: [PATCH] video4linux: Push down the BKL, Hans Verkuil, (Wed May 28, 2:13 am)
Re: [PATCH] video4linux: Push down the BKL, Andy Walls, (Tue May 27, 10:37 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Wed May 28, 4:34 am)
Re: [PATCH] video4linux: Push down the BKL, Devin Heitmueller, (Tue May 27, 10:47 pm)
Re: [PATCH] video4linux: Push down the BKL, Devin Heitmueller, (Tue May 27, 5:22 pm)
Re: [PATCH] video4linux: Push down the BKL, Mike Isely, (Sun May 25, 7:46 pm)
Re: [PATCH] video4linux: Push down the BKL, Hans Verkuil, (Fri May 23, 3:05 pm)
Re: [PATCH] video4linux: Push down the BKL , Jonathan Corbet, (Fri May 23, 9:56 am)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Fri May 23, 11:39 am)
Re: [PATCH] video4linux: Push down the BKL , Jonathan Corbet, (Fri May 23, 12:09 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Fri May 23, 2:58 pm)
Re: [PATCH] video4linux: Push down the BKL, Andy Walls, (Thu May 22, 10:08 pm)
Re: [PATCH] video4linux: Push down the BKL, Alan Cox, (Fri May 23, 5:09 am)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Mon May 26, 12:34 pm)
Re: [PATCH] video4linux: Push down the BKL, Hans Verkuil, (Mon May 26, 12:46 pm)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Mon May 26, 5:14 pm)
Re: [PATCH] video4linux: Push down the BKL, Hans Verkuil, (Fri May 23, 2:16 am)
Re: [PATCH] video4linux: Push down the BKL, Mauro Carvalho Chehab, (Mon May 26, 12:39 pm)
Re: [PATCH] video4linux: Push down the BKL, Hans Verkuil, (Fri May 23, 2:28 am)