Fix the x86-64 cache alignment code to take pgoff into account.
Use the x86 and MIPS cache alignment code as the basis for a generic
cache alignment function.
The old x86 code will always align the mmap to aliasing boundaries,
even if the program mmaps the file with a non-zero pgoff.
If program A mmaps the file with pgoff 0, and program B mmaps the
file with pgoff 1. The old code would align the mmaps, resulting in
misaligned pages:
A: 0123
B: 123
After this patch, they are aligned so the pages line up:
A: 0123
B: 123
Signed-off-by: Michel Lespinasse <wal...@google.com>
Proposed-by: Rik van Riel <r...@redhat.com>
---
arch/x86/kernel/sys_x86_64.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index f00d006d60fd..97ef74b88e0f 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -136,7 +136,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long
addr,
info.low_limit = begin;
info.high_limit = end;
info.align_mask = filp ? get_align_mask() : 0;
- info.align_offset = 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
return vm_unmapped_area(&info);
}
@@ -175,7 +175,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const
unsigned long addr0,
info.low_limit = PAGE_SIZE;
info.high_limit = mm->mmap_base;
info.align_mask = filp ? get_align_mask() : 0;
- info.align_offset = 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
addr = vm_unmapped_area(&info);
if (!(addr & ~PAGE_MASK))
return addr;
--
1.7.7.3
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
