From: Jack Stone <jwjstone@fastmail.fm>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mac <kmac@poczta.fm>,
linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org,
Greg Kroah-Hartman <gregkh@suse.de>
Subject: Re: 'scheduling while atomic' during ppp connection on 2.6.37.1 and 2.6.38
Date: Mon, 21 Mar 2011 17:40:32 +0000 [thread overview]
Message-ID: <4D878D90.6070100@fastmail.fm> (raw)
In-Reply-To: <20110321112723.248e7a52@lxorguk.ukuu.org.uk>
On 21/03/2011 11:27, Alan Cox wrote:
> It's quite likely that was as broken before your change as after. The
> locking in the code makes no sense so I flagged it up. The
> nozomi ntty_write also has lots of oddness in it that really needs
> sorting out.
>
> I suspect that the chunk
>
> if (!dc || !port)
> return -ENODEV;
>
> mutex_lock(&port->tty_sem);
>
> if (unlikely(!port->port.count)) {
> DBG1(" ");
> goto exit;
> }
>
> and
>
> /* notify card */
> if (unlikely(dc == NULL)) {
> DBG1("No device context?");
> goto exit;
> }
>
> and the mutex unlock are actually not doing anything
>
> On the write_room case I think that as the code already uses tty_port
> helpers it needs to simply just return the correct value and not do all
> the other checks. chars_in_buffer() likewise
>
> So in fact I don't think at this point the tty_sem needs replacing with
> anything, but the various bogus port.count checks want ripping out.
>
>
Thank you very much for the explanation. I will do my best to respin the
patch with appropriate changes.
Jack
next prev parent reply other threads:[~2011-03-21 17:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-19 22:06 'scheduling while atomic' during ppp connection on 2.6.37.1 and 2.6.38 Mac
2011-03-20 18:42 ` Jack Stone
2011-03-20 21:52 ` Jiri Slaby
2011-03-20 23:09 ` Jack Stone
2011-03-20 21:58 ` Alan Cox
2011-03-20 23:05 ` Jack Stone
2011-03-21 11:27 ` Alan Cox
2011-03-21 17:40 ` Jack Stone [this message]
2011-03-21 9:15 ` Jiri Slaby
2011-03-21 11:02 ` Alan Cox
2011-03-31 20:53 ` Jiri Slaby
2011-03-31 21:39 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2011-03-19 21:56 Mac
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