Ian Campbell c5cae661d6 xen: fix hang on suspend. ... In 65f63384 "xen: improve error handling in do_suspend" I said: - xs_suspend()/xs_resume() and dpm_suspend_noirq()/dpm_resume_noirq() were not nested in the obvious way. and changed the ordering of the calls as so: BEFORE AFTER xs_suspend dpm_suspend_noirq dpm_suspend_noirq xs_suspend *SUSPEND* *SUSPEND* dpm_resume_noirq dpm_resume_noirq xs_resume xs_resume Clearly this is not an improvement and I was talking rubbish. In particular the new ordering is susceptible to a hang if a xenstore write is in progress at the point at which the suspend kicks in. When the suspend process calls xs_suspend it tries to take the request_mutex but if a write is in progress it could be looping in xenbus_xs.c:read_reply() waiting for something to arrive on &xs_state.reply_list while holding the request_mutex (taken in the caller of read_reply). However if we have done dpm_suspend_noirq before xs_suspend then we won't get any more xenstore interrupts and process_msg() will never be woken up to add anything to the reply_list. Fix this by calling xs_suspend before dpm_suspend_noirq. If dpm_suspend_noirq fails then make sure we go through the xs_suspend_cancel() code path. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stable Kernel <stable@kernel.org>		2010-01-13 10:01:35 +00:00
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xenbus	Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6	2009-12-11 12:18:16 -08:00
xenfs	xen: move Xen-testing predicates to common header	2009-11-04 08:47:24 -08:00
balloon.c	Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6	2009-12-11 12:18:16 -08:00
cpu_hotplug.c	Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6	2009-12-11 12:18:16 -08:00
events.c	xen: don't leak IRQs over suspend/resume.	2009-12-03 11:14:55 -08:00
evtchn.c	xen: move Xen-testing predicates to common header	2009-11-04 08:47:24 -08:00
features.c
grant-table.c	xen: move Xen-testing predicates to common header	2009-11-04 08:47:24 -08:00
Kconfig	Merge commit 'origin/master' into for-linus/xen/master	2009-04-07 13:34:16 -07:00
Makefile	xen: make -fstack-protector work under Xen	2009-09-09 16:37:39 -07:00
manage.c	xen: fix hang on suspend.	2010-01-13 10:01:35 +00:00
sys-hypervisor.c	xen: move Xen-testing predicates to common header	2009-11-04 08:47:24 -08:00
xencomm.c