On Mon, May 30, 2011 at 9:45 PM, Tormod Volden wrote: > (*) It actually checks if _DRM_CONTAINS_LOCK is the /only/ flag set. I > suppose this is intentional. My v2 patch does not change anything in the > case of _DRM_SHM: If it contains a lock, it returns a match without > comparing offsets. If no lock, it compares the full offsets. Is this > because the only _DRM_SHM used by userspace is the one with a lock, so > there is never a need to check a userspace-provided offset, or are those > always within 32 bit so a full check is ok? After googling up an old "DRM map design" thread from 2005 (http://thread.gmane.org/gmane.comp.video.dri.devel/19545/focus=19689), and http://dri.freedesktop.org/wiki/DrmMapHandling I think I can answer this to some extent myself: For _DRM_SHM it is not an offset that is passed from/to userspace, but a handle, which I guess is kept within 32 bit. Although this is not fully clear to me after browsing through drm_addmap_core(), where the offset or handle is the result of vmalloc_user(). Tormod _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
