tree f4403f7ba381255e03fd1b01eccd57c57a7976e8
parent 1dbf37e8adf1ab6b82a510d5e69fa676ed9717c4
author NeilBrown <neilb@suse.de> 1179953889 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1179976454 -0700

md: avoid overflow in raid0 calculation with large components

If a raid0 has a component device larger than 4TB, and is accessed on a 32bit
machines, then as 'chunk' is unsigned long,

   chunk << chunksize_bits

can overflow (this can be as high as the size of the device in KB).  chunk
itself will not overflow (without triggering a BUG).

So change 'chunk' to be 'sector_t, and get rid of the 'BUG' as it becomes
impossible to hit.

Cc: "Jeff Zheng" <Jeff.Zheng@endace.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>