The patch titled
mm/shmem.c: fix division by zero
has been added to the -mm tree. Its filename is
mm-shmemc-fix-division-by-zero.patch
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Subject: mm/shmem.c: fix division by zero
From: Yuri Tikhonov <yur@xxxxxxxxxxx>
Fix a division by zero which we have in shmem_truncate_range() and
shmem_unuse_inode() when using big PAGE_SIZE values (e.g. 256KB on ppc44x).
With 256KB PAGE_SIZE the ENTRIES_PER_PAGEPAGE constant becomes too large
(0x1.0000.0000), so this patch just changes the types from 'ulong' to
'ullong' where it's necessary.
Signed-off-by: Yuri Tikhonov <yur@xxxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN mm/shmem.c~mm-shmemc-fix-division-by-zero mm/shmem.c
--- a/mm/shmem.c~mm-shmemc-fix-division-by-zero
+++ a/mm/shmem.c
@@ -65,7 +65,7 @@ static struct vfsmount *shm_mnt;
#include <asm/pgtable.h>
#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
-#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
+#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
#define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
@@ -103,7 +103,7 @@ static unsigned long shmem_default_max_i
}
#endif
-static int shmem_getpage(struct inode *inode, unsigned long idx,
+static int shmem_getpage(struct inode *inode, unsigned long long idx,
struct page **pagep, enum sgp_type sgp, int *type);
static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
@@ -541,7 +541,7 @@ static void shmem_truncate_range(struct
int punch_hole;
spinlock_t *needs_lock;
spinlock_t *punch_lock;
- unsigned long upper_limit;
+ unsigned long long upper_limit;
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
@@ -1183,7 +1183,7 @@ static inline struct mempolicy *shmem_ge
* vm. If we swap it in we mark it dirty since we also free the swap
* entry since a page cannot live in both the swap and page cache
*/
-static int shmem_getpage(struct inode *inode, unsigned long idx,
+static int shmem_getpage(struct inode *inode, unsigned long long idx,
struct page **pagep, enum sgp_type sgp, int *type)
{
struct address_space *mapping = inode->i_mapping;
_
Patches currently in -mm which might be from yur@xxxxxxxxxxx are
mm-shmemc-fix-division-by-zero.patch
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