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Subject[PATCH] mm: pagewalk: call pte_hole() for VM_PFNMAP during walk_page_range
Date
walk_page_range silently skips vma having VM_PFNMAP set,
which leads to undesirable behaviour at client end (who
called walk_page_range). For example for pagemap_read,
when no callbacks are called against VM_PFNMAP vma,
pagemap_read may prepare pagemap data for next virtual
address range at wrong index.

Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>
---
The fix is revised, based upon the suggestion here at
http://www.spinics.net/lists/linux-mm/msg83058.html

mm/pagewalk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index ad83195..b264bda 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -199,7 +199,10 @@ int walk_page_range(unsigned long addr, unsigned long end,
*/
if ((vma->vm_start <= addr) &&
(vma->vm_flags & VM_PFNMAP)) {
- next = vma->vm_end;
+ if (walk->pte_hole)
+ err = walk->pte_hole(addr, next, walk);
+ if (err)
+ break;
pgd = pgd_offset(walk->mm, next);
continue;
}
--
Shiraz Hashim
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation



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