[PATCH 3.19.y-ckt 82/86] nfs: fix pg_test page count calculation

From: Kamal Mostafa
Date: Tue Oct 27 2015 - 17:49:09 EST


3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>

commit 048883e0b934d9a5103d40e209cb14b7f33d2933 upstream.

We really want sizeof(struct page *) instead. Otherwise we limit
maximum IO size to 64 pages rather than 512 pages on a 64bit system.

Fixes 2e11f829(nfs: cap request size to fit a kmalloced page array).

Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
Fixes: 2e11f8296d22 ("nfs: cap request size to fit a kmalloced page array")
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
fs/nfs/pagelist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 227c53d..9544693 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -491,7 +491,7 @@ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
* for it without upsetting the slab allocator.
*/
if (((desc->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
- sizeof(struct page) > PAGE_SIZE)
+ sizeof(struct page *) > PAGE_SIZE)
return 0;

return min(desc->pg_bsize - desc->pg_count, (size_t)req->wb_bytes);
--
1.9.1

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