From: Oliver Neukum <oneukum@suse.de>
To: Ming Lei <ming.lei@canonical.com>
Cc: linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-pm@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>
Subject: Re: [RFC PATCH 3/3] USB: forbid memory allocation with I/O during bus reset if storage interface exits
Date: Mon, 15 Oct 2012 11:34:33 +0200 [thread overview]
Message-ID: <2564763.3cNFlv543H@linux-lqwf.site> (raw)
In-Reply-To: <1350278059-14904-4-git-send-email-ming.lei@canonical.com>
On Monday 15 October 2012 13:14:19 Ming Lei wrote:
> If one storage interface exists in the device, memory allocation
> with GFP_KERNEL during usb_device_reset() might trigger I/O transfer
> on the storage interface itself and cause deadlock because the
> 'us->dev_mutex' is held in .pre_reset() and the storage interface
> can't do I/O transfer when the reset is triggered by other
> interface, or the error handling can't be completed if the reset
> is triggered by mass storage itself(error handling path).
I think limiting this to devices which have a storage device is not
productive. What if you are using iSCSI or nbd? In the long run
we will see busses attached to busses and as soon as the daughter
bus is hotpluggable you are thwarted anyway. Just do it unconditionally.
Regards
Oliver
next prev parent reply other threads:[~2012-10-15 9:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-15 5:14 [RFC PATCH 0/3] mm/PM/USB: force memory allocation with no io in need Ming Lei
2012-10-15 5:14 ` [RFC PATCH 1/3] mm: teach mm by current context info to not do I/O during memory allocation Ming Lei
2012-10-15 14:33 ` Alan Stern
2012-10-15 14:41 ` Ming Lei
2012-10-15 15:47 ` Minchan Kim
2012-10-16 1:56 ` Ming Lei
2012-10-16 5:49 ` Minchan Kim
2012-10-16 7:08 ` Ming Lei
2012-10-16 13:09 ` Minchan Kim
2012-10-16 13:47 ` Ming Lei
2012-10-16 13:53 ` Minchan Kim
2012-10-15 5:14 ` [RFC PATCH 2/3] PM / Runtime: force memory allocation with no I/O during runtime_resume callbcack Ming Lei
2012-10-15 14:14 ` Alan Stern
2012-10-15 14:35 ` Ming Lei
2012-10-15 5:14 ` [RFC PATCH 3/3] USB: forbid memory allocation with I/O during bus reset if storage interface exits Ming Lei
2012-10-15 9:34 ` Oliver Neukum [this message]
2012-10-15 12:06 ` Ming Lei
2012-10-15 12:30 ` Oliver Neukum
2012-10-15 13:21 ` Ming Lei
2012-10-15 16:04 ` Oliver Neukum
2012-10-15 16:48 ` Greg Kroah-Hartman
2012-10-16 7:41 ` Ming Lei
2012-10-15 16:48 ` Greg Kroah-Hartman
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