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From: Hayes Wang <hayeswang@realtek.com>
To: David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	nic_swsd <nic_swsd@realtek.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: RE: [PATCH net-next] r8152: use mutex for hw settings
Date: Thu, 9 Oct 2014 07:59:35 +0000	[thread overview]
Message-ID: <0835B3720019904CB8F7AA43166CEEB2EC397B@RTITMBSTEMP01.realtek.com.tw> (raw)
In-Reply-To: <20141008.154513.1944594723904521723.davem@davemloft.net>

 David Miller [mailto:davem@davemloft.net] 
> Sent: Thursday, October 09, 2014 3:45 AM
[..]
> I think a much simpler fix is to take rtnl_lock() in the workqueue
> function and suspend/resume ops.
> 
> Every other place you are adding the mutex already holds the RTNL
> mutex.

If I use the rtnl_lock(), I get a dead lock when enabling autosuspend.

Case 1:
   autosuspend before calling open.
   rtnl_lock()
   call open
   try to autoresume and rtl8152_resume is called.
   dead lock occurs.

Case 2:
   autosuspend occurs.
   rtnl_lock()
   call close
   try to autoresume and rtl8152_resume is called.
   dead lock occurs.
 
Best Regards,
Hayes

  reply	other threads:[~2014-10-09  8:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-07  5:36 Hayes Wang
2014-10-08 19:45 ` David Miller
2014-10-09  7:59   ` Hayes Wang [this message]
2014-10-09 23:05     ` David Miller
2014-10-09  6:24 ` [PATCH net-next] r8152: add rtnl_lock Hayes Wang
2014-10-09  7:59   ` Hayes Wang
2014-10-09 10:00 ` [PATCH net-next v2 0/3] r8152: use mutex for hw settings Hayes Wang
2014-10-09 10:00   ` [PATCH net-next v2 1/3] r8152: autoresume before setting feature Hayes Wang
2014-10-09 10:00   ` [PATCH net-next v2 2/3] r8152: adjust usb_autopm_xxx Hayes Wang
2014-10-09 10:00   ` [PATCH net-next v2 3/3] r8152: add mutex for hw settings Hayes Wang
2014-10-09 23:06   ` [PATCH net-next v2 0/3] r8152: use " David Miller

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