From: Ilija Hadzic Date: Fri, 28 Oct 2011 21:43:28 +0000 (-0400) Subject: drm: make DRM_UNLOCKED ioctls with their own mutex X-Git-Tag: v3.3-rc1~121^2~17 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=09b4ea47d1041612b101c369969db123ac2c1511;p=pandora-kernel.git drm: make DRM_UNLOCKED ioctls with their own mutex drm_getclient, drm_getstats and drm_getmap (with a few minor adjustments) do not need global mutex, so fix that and make the said ioctls DRM_UNLOCKED. Details: drm_getclient: the only thing that should be protected here is dev->filelist and that is already protected everywhere with dev->struct_mutex. drm_getstats: there is no need for any mutex here because the loop runs through quasi-static (set at load time only) data, and the actual count access is done with atomic_read() drm_getmap already uses dev->struct_mutex to protect dev->maplist, which also used to protect the same structure everywhere else except at three places: * drm_getsarea, which doesn't grab *any* mutex before touching dev->maplist (so no drm_global_mutex doesn't help here either; different issue for a different patch). However, drivers seem to call it only at initialization time so it probably doesn't matter * drm_master_destroy, which is called from drm_master_put, which in turn is protected with dev->struct_mutex everywhere else in drm module, so we are good here too. * drm_getsareactx, which releases the dev->struct_mutex too early, but this patch includes the fix for that. v2: * incorporate comments received from Daniel Vetter * include the (long) explanation above to make it clear what we are doing (and why), also at Daniel Vetter's request * tighten up mutex grab/release locations to only encompass real critical sections, rather than some random code around them Signed-off-by: Ilija Hadzic Reviewed-by: Daniel Vetter Signed-off-by: Dave Airlie --- Reading git-diff-tree failed