linux/include
Prarit Bhargava 6af8bef14d PCI hotplug: acpiphp: Prevent deadlock on PCI-to-PCI bridge remove
I originally submitted a patch to workaround this by pushing all Ejection
Requests and Device Checks onto the kacpi_hotplug queue.

http://marc.info/?l=linux-acpi&m=131678270930105&w=2

The patch is still insufficient in that Bus Checks also need to be added.

Rather than add all events, including non-PCI-hotplug events, to the
hotplug queue, mjg suggested that a better approach would be to modify
the acpiphp driver so only acpiphp events would be added to the
kacpi_hotplug queue.

It's a longer patch, but at least we maintain the benefit of having separate
queues in ACPI.  This, of course, is still only a workaround the problem.
As Bjorn and mjg pointed out, we have to refactor a lot of this code to do
the right thing but at this point it is a better to have this code working.

The acpi core places all events on the kacpi_notify queue.  When the acpiphp
driver is loaded and a PCI card with a PCI-to-PCI bridge is removed the
following call sequence occurs:

cleanup_p2p_bridge()
	    -> cleanup_bridge()
		    -> acpi_remove_notify_handler()
			    -> acpi_os_wait_events_complete()
				    -> flush_workqueue(kacpi_notify_wq)

which is the queue we are currently executing on and the process will hang.

Move all hotplug acpiphp events onto the kacpi_hotplug workqueue.  In
handle_hotplug_event_bridge() and handle_hotplug_event_func() we can simply
push the rest of the work onto the kacpi_hotplug queue and then avoid the
deadlock.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: mjg@redhat.com
Cc: bhelgaas@google.com
Cc: linux-acpi@vger.kernel.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-10-14 09:05:31 -07:00
..
acpi PCI hotplug: acpiphp: Prevent deadlock on PCI-to-PCI bridge remove 2011-10-14 09:05:31 -07:00
asm-generic All Arch: remove linkage for sys_nfsservctl system call 2011-08-26 15:09:58 -07:00
crypto
drm drm: Separate EDID Header Check from EDID Block Check 2011-08-04 14:39:35 +01:00
keys
linux PCI / PM: Extend PME polling to all PCI devices 2011-10-14 09:05:31 -07:00
math-emu
media [media] V4L: initial driver for ov5642 CMOS sensor 2011-07-27 17:56:09 -03:00
mtd
net tcp: fix build error if !CONFIG_SYN_COOKIES 2011-09-18 21:48:01 -04:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2011-07-31 06:23:08 -10:00
rdma atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
rxrpc atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
scsi Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 2011-08-06 22:56:03 -07:00
sound ASoC: omap: Update e-mail address of Jarkko Nikula 2011-08-12 11:45:10 +09:00
target target: Make standard INQUIRY return 'not connected' for tpg_virt_lun0 2011-08-22 19:25:35 +00:00
trace writeback: show raw dirtied_when in trace writeback_single_inode 2011-08-31 08:48:15 +08:00
video OMAP: DSS2: Remove unused opt_clock_available 2011-07-25 10:22:05 +03:00
xen xen/balloon: memory hotplug support for Xen balloon driver 2011-07-25 20:57:08 -07:00
Kbuild