From: Oliver Neukum <oliver@neukum.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Greg KH <greg@kroah.com>,
Kernel development list <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>
Subject: Re: [PATCH 4/5] usb_serial: Kill port mutex
Date: Thu, 8 Oct 2009 15:43:01 +0200 [thread overview]
Message-ID: <200910081543.01933.oliver@neukum.org> (raw)
In-Reply-To: <Pine.LNX.4.44L0.0910071720440.4512-100000@iolanthe.rowland.org>
Am Mittwoch, 7. Oktober 2009 23:34:12 schrieb Alan Stern:
> I'm losing track of the original point of this thread. IIRC, the
> problem is how the resume method should know whether or not to submit
> the receive URB(s). It can't afford to acquire the port mutex because
> it might be called by open or close, at which time the mutex is already
> held.
>
> Other schemes could work, but to me it seems simplest to rely on a flag
> protected by a spinlock. The flag would mean "URBs are supposed to be
> queued unless we are suspended". It would be set by open and
> unthrottle, and cleared by close and throttle.
1. Why a spinlock?
2. Can we get by with only one flag?
Regards
Oliver
next prev parent reply other threads:[~2009-10-08 13:41 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-06 15:05 [PATCH 0/5] tty_port_open Alan Cox
2009-10-06 15:06 ` [PATCH 1/5] tty_port: add "tty_port_open" helper Alan Cox
2009-10-06 15:06 ` [PATCH 2/5] tty_port: coding style cleaning pass Alan Cox
2009-10-06 15:06 ` [PATCH 3/5] usb_serial: Use the shutdown() operation Alan Cox
2009-10-06 15:06 ` [PATCH 4/5] usb_serial: Kill port mutex Alan Cox
2009-10-07 5:02 ` Oliver Neukum
2009-10-07 16:03 ` Alan Stern
2009-10-07 16:10 ` Oliver Neukum
2009-10-07 16:34 ` Alan Stern
2009-10-07 16:46 ` Alan Cox
2009-10-07 17:23 ` Alan Stern
2009-10-07 18:25 ` Alan Cox
2009-10-07 18:52 ` Alan Stern
2009-10-07 20:56 ` Oliver Neukum
2009-10-07 21:02 ` Alan Cox
2009-10-07 21:34 ` Alan Stern
2009-10-08 13:43 ` Oliver Neukum [this message]
2009-10-08 14:58 ` Alan Stern
2009-10-08 15:27 ` Oliver Neukum
2009-10-08 16:58 ` Alan Stern
2009-10-08 20:06 ` Alan Stern
2009-10-08 20:40 ` Oliver Neukum
2009-10-08 21:19 ` Alan Cox
2009-10-08 21:31 ` Alan Stern
2009-10-08 22:31 ` Alan Cox
2009-10-08 11:37 ` Oliver Neukum
2009-10-06 15:06 ` [PATCH 5/5] opticon: Fix resume logic Alan Cox
2009-10-06 21:12 ` Oliver Neukum
2009-10-06 22:23 ` Alan Cox
2009-10-07 15:56 ` Johan Hovold
2009-10-07 16:01 ` Oliver Neukum
2009-10-07 15:56 ` Alan Stern
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