[60/93] devmem: fix kmem write bug on memory holes

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

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


From: Wu Fengguang <fengguang.wu@xxxxxxxxx>


commit c85e9a97c4102ce2e83112da850d838cfab5ab13 upstream

devmem: fix kmem write bug on memory holes

[ cebbert@xxxxxxxxxx : backport to 2.6.32 ]

write_kmem() used to assume vwrite() always return the full buffer length.
However now vwrite() could return 0 to indicate memory hole.  This
creates a bug that "buf" is not advanced accordingly.

Fix it to simply ignore the return value, hence the memory hole.

Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Chuck Ebbert <cebbert@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/char/mem.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -593,7 +593,7 @@ static ssize_t write_kmem(struct file *
 					break;
 				}
 			}
-			len = vwrite(kbuf, (char *)p, len);
+			vwrite(kbuf, (char *)p, len);
 			count -= len;
 			buf += len;
 			virtr += len;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/