Re: [PATCH] lib/checksum.c: optimize do_csum a bit

From: David Miller
Date: Thu Jul 07 2011 - 07:29:39 EST


From: Ian Abbott <abbotti@xxxxxxxxx>
Date: Thu, 7 Jul 2011 12:18:49 +0100

> Reduce the number of variables modified by the loop in do_csum() by 1,
> which seems like a good idea. On Nios II (a RISC CPU with 3-operand
> instruction set) it reduces the loop from 7 to 6 instructions, including
> the conditional branch.
>
> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>

I think you'll overshoot past the end of the buffer when there are
trailing bytes to handle.

The whole reason we need the count variable is to handle those
kinds of cases.
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