From: Nicolas Pitre <nico@cam.org>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] small tty irq race fix
Date: Mon, 3 Mar 2003 16:51:42 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44.0303031650230.31566-100000@xanadu.home> (raw)
In-Reply-To: <Pine.LNX.4.44.0303031338260.12285-100000@home.transmeta.com>
On Mon, 3 Mar 2003, Linus Torvalds wrote:
>
> On Mon, 3 Mar 2003, Nicolas Pitre wrote:
> >
> > What about this one? It just happens that tty->read_lock is actually used
> > deeper in the same call instance (in n_tty.c) so this looks to be the best
> > lock to use.
>
> Looks ok. I would suggest moving the "spin_lock_irqsave()" to outside the
> 'if'-statement, though, since that should make the code a lot more
> readable, and if the lock is supposed to protect tty->flip.buf_num, then
> let's do it right and protect the read as well, no?
Oh sure.
--- linux-2.5.63/drivers/char/tty_io.c.orig Mon Feb 24 14:05:34 2003
+++ linux-2.5.63/drivers/char/tty_io.c Mon Mar 3 16:49:44 2003
@@ -1944,27 +1944,25 @@
schedule_delayed_work(&tty->flip.work, 1);
return;
}
+
+ spin_lock_irqsave(&tty->read_lock, flags);
if (tty->flip.buf_num) {
cp = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
fp = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
tty->flip.buf_num = 0;
-
- local_irq_save(flags); // FIXME: is this safe?
tty->flip.char_buf_ptr = tty->flip.char_buf;
tty->flip.flag_buf_ptr = tty->flip.flag_buf;
} else {
cp = tty->flip.char_buf;
fp = tty->flip.flag_buf;
tty->flip.buf_num = 1;
-
- local_irq_save(flags); // FIXME: is this safe?
tty->flip.char_buf_ptr = tty->flip.char_buf + TTY_FLIPBUF_SIZE;
tty->flip.flag_buf_ptr = tty->flip.flag_buf + TTY_FLIPBUF_SIZE;
}
count = tty->flip.count;
tty->flip.count = 0;
- local_irq_restore(flags); // FIXME: is this safe?
-
+ spin_unlock_irqrestore(&tty->read_lock, flags);
+
tty->ldisc.receive_buf(tty, cp, fp, count);
}
Nicolas
prev parent reply other threads:[~2003-03-03 21:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-03-03 18:09 [patch] small tty irq race fix Nicolas Pitre
2003-03-03 20:06 ` Alan Cox
2003-03-03 19:15 ` Nicolas Pitre
2003-03-03 21:20 ` Nicolas Pitre
2003-03-03 21:39 ` Linus Torvalds
2003-03-03 21:51 ` Nicolas Pitre [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Pine.LNX.4.44.0303031650230.31566-100000@xanadu.home \
--to=nico@cam.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@transmeta.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).