lkml.org 
[lkml]   [2006]   [Jun]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH][RFC] kill TTY_DONT_FLIP
Alan Cox wrote:
> Looks good to me on a first review.

I looked at the paths taken by n_tty_receive_buf()
for how they would effect read_chan():

* tty state (put_tty_queue,eraser,finish_erasing,etc)
* read wakeups
* start_tty/stop_tty
* put_char/opost

everything looks OK without TTY_DONT_FLIP

2.0.X relied on the BKL (and dinosaurs roamed the Earth)

2.1.X introduced TTY_DONT_FLIP to prevent read_chan and
n_tty_receive_buf from executing at the same time.

2.2.15 added tty->read_lock around the N_TTY read buffer,
which is the only thing needing protection in this context.

The usual progression to finer grained locking.
This looks like a safe removal.

The review also revealed a spot in reset_buffer_flags()
where tty->read_lock needs to be extended around
modifications of canon_head, canon_data, and read_flags.
I'll make a patch for that.

--
Paul Fulghum
Microgate Systems, Ltd.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-06-23 16:02    [W:0.090 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site