lkml.org 
[lkml]   [2007]   [May]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [GIT PULL] MMC updates
Nick Piggin wrote:
>
> If you want to ensure you always only modify host->removed from under
> the spinlock, it would be enforcable by introducing an accessor function
> and doing a BUG_ON(!spin_is_locked()) in there.
>
> If you just want to ensure that host->removed is 0 at this point, you
> shouldn't need any spinlocks AFAIKS... that way you can probably afford
> to move it out from CONFIG_MMC_DEBUG and get wider testing.
>

The host->removed member is only used for this simple test. It is set in
mmc_host_remove() to indicate that the removal process has begun. At
this point it is invalid to call mmc_detect_change() (the place this
patch fixes). So the spinlocks are mostly there so that things are
properly ordered when we go SMP. Some creative barriers would probably
work as well, but I find spinlocks more "normal" and hence more readable.

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: 2007-05-09 09:55    [W:0.498 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site