From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Pavan Savoy <pavan_savoy@sify.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: locks inside receive_buf
Date: Thu, 31 Mar 2011 11:25:59 +0100 [thread overview]
Message-ID: <20110331112559.090948a7@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <AANLkTi=FrmB=u09wvLoXzQstnV3h-U58R728t3k6_-B-@mail.gmail.com>
On Wed, 30 Mar 2011 17:51:27 +0530
Pavan Savoy <pavan_savoy@sify.com> wrote:
> Hi,
>
> Does holding a lock make any sense inside the line discipline's
> ops->receive_buf?
> I see the locks being held and released - during some calls like
> flush_to_ldisc, which end up calling receive_buf....
>
>
> and yes, I would like to have a lock because, there are other
> functions in my ldisc driver executed in process context ...
> Is there some hints as to what should be the do's and don'ts inside
> the ldisc ops functions ? (say tty_wakeup ...)
It's not well documented no. Your ld->receive_buf is single threaded and
runs from a sleeping context (but please don't sleep too long)
The output path from user space will be in a sleeping context too, but
you can call the write method of the tty your driver is using from
interrupt context or holding a spinlock (eg from timers)
next prev parent reply other threads:[~2011-03-31 10:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-30 12:21 Pavan Savoy
2011-03-31 10:25 ` Alan Cox [this message]
2011-03-31 11:18 ` Pavan Savoy
2011-03-31 14:33 ` Steven Rostedt
2011-04-01 7:12 ` Pavan Savoy
2011-04-01 13:46 ` Steven Rostedt
2011-04-05 11:13 ` Pavan Savoy
2011-04-05 13:04 ` Steven Rostedt
2011-04-06 8:56 ` Pavan Savoy
2011-05-17 11:30 ` Pavan Savoy
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