lkml.org 
[lkml]   [2007]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] [PATCH] Fix up needless kmap:s
Alex Dubov wrote:
> The patch looks ok.
>
> However, due to certain peculiarities with memorystick and xd I have to emulate a scatter-gather
> in software. Considering that this particular aspect of implementation is the same for all card
> types on this TI chip, it can be shared by tifm_sd driver as well. In this case highmem won't be
> needed to be avoided and kmap_atomic will come back (may be).
>
>

Fair enough. Just make sure you handle the big problem case (kmap only
maps a single page, not the entire sg entry).

> And, by the way, to what extent pagefault_enable/pagefault_disable calls are needed? They are
> present in k(u)map_atomic even for non-highmem pages/architectures.
>
>

They tell the page fault handler that it may not sleep on a page fault.
Currently it only has the behaviour of disabling preemption though. I'd
guess it is present for non-highmem so that things behave somewhat
similar for both the highmem and non-highmem cases.

Rgds

--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
PulseAudio, core developer http://pulseaudio.org
rdesktop, core developer http://www.rdesktop.org

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-02-04 17:53    [W:0.051 / U:0.504 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site