Re: [PATCH] fb: convert lock/unlock_kernel() into local fb mutex
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From: Andrew Morton <akpm@linux-foundation.org>
Date: 2008-08-05 09:01:10
On Tue, 5 Aug 2008 07:37:55 +0200 Krzysztof Helt [off-list ref] wrote:
From: Krzysztof Helt <redacted> Change lock_kernel()/unlock_kernel() to local fb mutex. Each frame buffer instance has its own mutex. The one line try_to_load() function is unrolled to request_module() in two places for readability. Signed-off-by: Krzysztof Helt <redacted> --- The only caveat is that I had to put request_module() call outside this new mutex while it was inside the lock_kernel() (inside fb_open()).
Why did you have to do that? The request_module() in fb_ioctl() is inside the lock...
If the request_module() should be called only inside this mutex please drop the patch.
No, request_module() doesn't need lock_kernel(). The only possible problem I can see is the sole remaining lock_kernel() in drivers/video/console/vgacon.c. The fbcon.c code used to be serialised against vgacon_do_font_op() via lock_kernel, but with this change vgacon_do_font_op() can now run concurrently with all the code which you've put inside fb_info.mutex_lock. Probably not a problem, but please check that sometime. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/