On Sat, Dec 21, 2013 at 12:03:55PM +0100, Johan Hovold wrote:
> Fix race in generic write implementation, which could lead to
> temporarily degraded throughput.
>
> The current generic write implementation introduced by commit
> 27c7acf22047 ("USB: serial: reimplement generic fifo-based writes") has
> always had this bug, although it's fairly hard to trigger and the
> consequences are not likely to be noticed.
>
> Specifically, a write() on one CPU while the completion handler is
> running on another could result in only one of the two write urbs being
> utilised to empty the remainder of the write fifo (unless there is a
> second write() that doesn't race during that time).
>
> Cc: stable <stable@xxxxxxxxxxxxxxx> # 2.6.35
> Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>
> Backport of commit 6f6485463aad ("USB: serial: fix race in generic write") to
> v3.12. Applies cleanly also to v3.4 and v3.10.
Thanks for the backport, now applied.
greg k-h
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