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List:       v9fs-developer
Subject:    Re: [V9fs-developer] [V9fs-users] 9p read blocks suspend-to-ram
From:       sqweek <sqweek () gmail ! com>
Date:       2014-03-07 8:20:26
Message-ID: CAM104AWzOFffy6oo6dexWBtw_GKxYa0xBniJrkmZ=EA49DEQxw () mail ! gmail ! com
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On 7 March 2014 14:36, sqweek <sqweek@gmail.com> wrote:
> I see some read() syscalls fail with ERESTARTSYS when the system is
> suspended (eg. strace cat /dev/input/mice). p9_client_rpc seems to
> take this as a signal to cancel the pending rpc?

And, since the userspace server has already been frozen at this point,
it cannot read the flush request and the send blocks?

*If* the 9pnet kernel thread is freezable (which is not the default),
I think that using wait_event_freezable() instead of
wait_event_interruptible() will allow the system to sleep by delaying
the RFlush until we wake up again (and the userspace server soon
unfreezes). Whether the stream continues after this depends on how the
server reacts to the RFlush, and how the kernel reacts to the
ERESTARTSYS...

-sqweek

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