On Sun, May 21, 2023 at 10:49 PM Hugh Dickins <hughd@xxxxxxxxxx> wrote: > > Use pmdp_get_lockless() in preference to READ_ONCE(*pmdp), to get a more > reliable result with PAE (or READ_ONCE as before without PAE); and remove > the unnecessary extra barrier()s which got left behind in its callers. > > HOWEVER: Note the small print in linux/pgtable.h, where it was designed > specifically for fast GUP, and depends on interrupts being disabled for > its full guarantee: most callers which have been added (here and before) > do NOT have interrupts disabled, so there is still some need for caution. > > Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx> The previous ask here: https://lore.kernel.org/r/CAOUHufZo=fB2HcaCrj2aidLJ2zEhOpi7ou5M_7qOQiuQq8+wTQ@xxxxxxxxxxxxxx/
