https://github.com/torvalds/linux
Revision ad4b3fb7ff9940bcdb1e4cd62bd189d10fa636ba authored by Christoffer Dall on 21 December 2012, 18:03:50 UTC, committed by Linus Torvalds on 26 December 2012, 22:57:34 UTC
Unfortunately with !CONFIG_PAGEFLAGS_EXTENDED, (!PageHead) is false, and (PageHead) is true, for tail pages. If this is indeed the intended behavior, which I doubt because it breaks cache cleaning on some ARM systems, then the nomenclature is highly problematic. This patch makes sure PageHead is only true for head pages and PageTail is only true for tail pages, and neither is true for non-compound pages. [ This buglet seems ancient - seems to have been introduced back in Apr 2008 in commit 6a1e7f777f61: "pageflags: convert to the use of new macros". And the reason nobody noticed is because the PageHead() tests are almost all about just sanity-checking, and only used on pages that are actual page heads. The fact that the old code returned true for tail pages too was thus not really noticeable. - Linus ] Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Will Deacon <Will.Deacon@arm.com> Cc: Steve Capper <Steve.Capper@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: stable@kernel.org # 2.6.26+ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 637704c
Tip revision: ad4b3fb7ff9940bcdb1e4cd62bd189d10fa636ba authored by Christoffer Dall on 21 December 2012, 18:03:50 UTC
mm: Fix PageHead when !CONFIG_PAGEFLAGS_EXTENDED
mm: Fix PageHead when !CONFIG_PAGEFLAGS_EXTENDED
Tip revision: ad4b3fb
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