hugepage: fix broken check for offset alignment in hugepage mappings
commitdec4ad86c2fbea062e9ef9caa6d6e79f7c5e0b12
authorDavid Gibson <david@gibson.dropbear.id.au>
Fri, 31 Aug 2007 06:56:40 +0000 (30 23:56 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Fri, 31 Aug 2007 08:42:23 +0000 (31 01:42 -0700)
tree9882d3b1f59fb293cf0f70afc80bdc7bb1e0021e
parent4a58448b0a375f7198de34dd0d3e2881afeaf025
hugepage: fix broken check for offset alignment in hugepage mappings

For hugepage mappings, the file offset, like the address and size, needs to
be aligned to the size of a hugepage.

In commit 68589bc353037f233fe510ad9ff432338c95db66, the check for this was
moved into prepare_hugepage_range() along with the address and size checks.
 But since BenH's rework of the get_unmapped_area() paths leading up to
commit 4b1d89290b62bb2db476c94c82cf7442aab440c8, prepare_hugepage_range()
is only called for MAP_FIXED mappings, not for other mappings.  This means
we're no longer ever checking for an aligned offset - I've confirmed that
mmap() will (apparently) succeed with a misaligned offset on both powerpc
and i386 at least.

This patch restores the check, removing it from prepare_hugepage_range()
and putting it back into hugetlbfs_file_mmap().  I'm putting it there,
rather than in the get_unmapped_area() path so it only needs to go in one
place, than separately in the half-dozen or so arch-specific
implementations of hugetlb_get_unmapped_area().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/i386/mm/hugetlbpage.c
arch/ia64/mm/hugetlbpage.c
arch/sparc64/mm/hugetlbpage.c
fs/hugetlbfs/inode.c
include/linux/hugetlb.h