[PATCH 2/3] spufs: fix another off-by-one bug in mbox_read

Arnd Bergmann arnd at arndb.de
Wed Oct 25 05:58:32 EST 2006

On Tuesday 24 October 2006 21:53, Will Schmidt wrote:
> Hey Arnd,
>    just curiosity..   What was the behavior before this patch?   just
> leaving a few (0 - 3) characters behind?

It transfers more bytes than requested on a read. If you asked for
four bytes, you got eight.

Note: one nasty property of this file in spufs is that you can only
read multiples of four bytes in the first place, there is no way to
atomically put back a few bytes into the hardware register, so reading
less than four bytes returns -EINVAL. Asking for more than four
should return the largest possible multiple of four.

	Arnd <><

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