Re: [PATCH] TTY: Fix loss of echoed characters (2nd follow-on PATCH attached)

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 09 Sep 2008 14:42:12 -0600
Joe Peterson <joe@skyrush.com> wrote:

> 1) Fix tab erasure handling
> 2) Improve locking when working with the echo buffer
> 3) Remove the big kernel lock (BKL) from n_tty
> 
> Tab erasure handling is now more robust and able to handle non-zero
> canon column cases more correctly.  This is done by making correct use
> of what is known in the eraser function (read buffer contents) and what
> is known at the time of processing the tab erasure (column state).
> 
> Also, better locking of the echo buffer will now prevent any attempts to
> process partial multi-byte echo operations.  And since the echo buffer
> code now isolates the tty column state code to the process_out* and
> process_echoes functions, we can remove the big kernel lock (BKL)
> and replace it with more modern mutex locks.

Boy.  Has this been carefully tested with lockdep enabled?