Re: [XTF] xenbus: fix xenbus_write() ring overflow

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 03/06/2020 09:21, Pawel Wieczorkiewicz wrote:
> Currently the xenbus_write() does not handle ring wrapping around
> correctly. When ring buffer is almost full and there is not enough
> space for next packet (e.g. there is 12 bytes of space left, but the
> packet header needs to transmit 16 bytes) the memcpy() goes out of the
> ring buffer boundry.
> Instead, the part variable should be limited to the space available in
> the ring buffer, so the memcpy() can fill up the buffer, update len
> variable (to indicate that there is still some data to be copied) and
> thereby the xenbus_write() loop can iterate again to finish copying
> the remainder of data to the beginning of the ring buffer.
>
> Signed-off-by: Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>

Oops.  Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> and pushed.