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From: Oliver Neukum <oneukum@suse.com>
To: guido@kiener-muenchen.de
Cc: dpenkler@gmail.com, steve_bayless@keysight.com,
	Greg KH <gregkh@linuxfoundation.org>,
	pankaj.adhikari@ni.com, guido.kiener@rohde-schwarz.com,
	linux-usb@vger.kernel.org
Subject: [02/12] usb: usbtmc: Support Read Status Byte with SRQ per file handle
Date: Sat, 26 May 2018 17:29:17 +0200	[thread overview]
Message-ID: <1527348557.26281.2.camel@suse.com> (raw)

Am Donnerstag, den 24.05.2018, 12:31 +0000 schrieb guido@kiener-
muenchen.de:
> Zitat von Oliver Neukum <oneukum@suse.com>:
> 
> > Am Montag, den 21.05.2018, 21:00 +0000 schrieb guido@kiener-
> > muenchen.de:
> > > 
> > > I looked for a race here, but I do not find a race between open and release,
> > > since a refcount of "file_data->data->kref" is always hold by
> > > usbtmc_probe/disconnect.
> > > 
> > > However I see a race between usbtmc_open and usbtmc_disconnect. Are these
> > > callback functions called mutual exclusive?
> > 
> > No, they are not.
> 
> In the meantime I found these conflictive hints:
> 
> https://github.com/torvalds/linux/commit/52a749992ca6a0fd304609af40ed3bfd6cef4660
> and
> https://elixir.bootlin.com/linux/v4.17-rc6/source/include/linux/usb.h#L1164
> 
> What do you think?
> My current feeling is that open/disconnect is mutual exclusive.
> We also could verify what really happens.

Ok, I remember.

You are safe, if and only if you share the USB minor number space.

	Regards
		Oliver
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             reply	other threads:[~2018-05-26 15:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-26 15:29 Oliver Neukum [this message]
  -- strict thread matches above, loose matches on Subject: below --
2018-05-24 12:31 [02/12] usb: usbtmc: Support Read Status Byte with SRQ per file handle Guido Kiener
2018-05-23 11:47 Oliver Neukum
2018-05-21 21:00 Guido Kiener
2018-05-18 13:10 Greg Kroah-Hartman
2018-05-18 12:36 Guido Kiener
2018-05-18 12:02 Greg Kroah-Hartman
2018-05-18 11:52 Guido Kiener
2018-05-17 17:03 Guido Kiener
2018-05-17 16:56 Greg Kroah-Hartman
2018-05-17 16:44 Randy Dunlap
2018-05-17 16:20 Greg Kroah-Hartman

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