• Arnd Bergmann's avatar
    drm: convert drm_ioctl to unlocked_ioctl · ed8b6704
    Arnd Bergmann authored
    drm_ioctl is called with the Big Kernel Lock held,
    which shows up very high in statistics on vfs_ioctl.
    
    Moving the lock into the drm_ioctl function itself
    makes sure we blame the right subsystem and it gets
    us one step closer to eliminating the locked version
    of fops->ioctl.
    
    Since drm_ioctl does not require the lock itself,
    we only need to hold it while calling the specific
    handler. The 32 bit conversion handlers do not
    interact with any other code, so they don't need
    the BKL here either and can just call drm_ioctl.
    
    As a bonus, this cleans up all the other users
    of drm_ioctl which now no longer have to find
    the inode or call lock_kernel.
    
    [airlied: squashed the non-driver bits
    of the second patch in here, this provides
    the flag for drivers to use to select unlocked
    ioctls - but doesn't modify any drivers].
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    Cc: David Airlie <airlied@linux.ie>
    Cc: dri-devel@lists.sourceforge.net
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
    ed8b6704
i810_dma.c 32.6 KB