[PATCH] mm: hugepage accounting fix
2.6.15's hugepage faulting introduced huge_pages_needed accounting into
hugetlbfs: to count how many pages are already in cache, for spot check on
how far a new mapping may be allowed to extend the file. But it's muddled:
each hugepage found covers HPAGE_SIZE, not PAGE_SIZE. Once pages were
already in cache, it would overshoot, wrap its hugepages count backwards,
and so fail a harmless repeat mapping with -ENOMEM. Fixes the problem
found by Don Dupuis.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-By: Adam Litke <agl@us.ibm.com>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index f568102..b351952899 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -72,8 +72,8 @@
unsigned long start = vma->vm_start;
unsigned long end = vma->vm_end;
unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
- pgoff_t next = vma->vm_pgoff;
- pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
+ pgoff_t next = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
+ pgoff_t endpg = next + hugepages;
pagevec_init(&pvec, 0);
while (next < endpg) {