• Dave Hansen's avatar
    x86/mm: Use pte_none() to test for empty PTE · dcb32d99
    Dave Hansen authored
    The page table manipulation code seems to have grown a couple of
    sites that are looking for empty PTEs.  Just in case one of these
    entries got a stray bit set, use pte_none() instead of checking
    for a zero pte_val().
    
    The use pte_same() makes me a bit nervous.  If we were doing a
    pte_same() check against two cleared entries and one of them had
    a stray bit set, it might fail the pte_same() check.  But, I
    don't think we ever _do_ pte_same() for cleared entries.  It is
    almost entirely used for checking for races in fault-in paths.
    Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave@sr71.net>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Luis R. Rodriguez <mcgrof@suse.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Toshi Kani <toshi.kani@hp.com>
    Cc: dave.hansen@intel.com
    Cc: linux-mm@kvack.org
    Cc: mhocko@suse.com
    Link: http://lkml.kernel.org/r/20160708001915.813703D9@viggo.jf.intel.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    dcb32d99
pageattr.c 47.9 KB