• Krzysztof Helt's avatar
    fbdev: add mutex for fb_mmap locking · 537a1bf0
    Krzysztof Helt authored
    
    
    Add a mutex to avoid a circular locking problem between the mm layer
    semaphore and fbdev ioctl mutex through the fb_mmap() call.
    
    Also, add mutex to all places where smem_start and smem_len fields change
    so the mutex inside the fb_mmap() is actually used.  Changing of these
    fields before calling the framebuffer_register() are not mutexed.
    
    This is 2.6.31 material.  It removes one lockdep (fb_mmap() and
    register_framebuffer()) but there is still another one (fb_release() and
    register_framebuffer()).  It also cleans up handling of the smem_start and
    smem_len fields used by mutexed section of the fb_mmap().
    Signed-off-by: default avatarKrzysztof Helt <krzysztof.h1@wp.pl>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
    Cc: <stable@kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    537a1bf0
w100fb.c 47.9 KB