linux-stable/drivers/xen/xenbus
David Woodhouse 5f46400f7a xen: Fix XenStore initialisation for XS_LOCAL
In commit 3499ba8198 ("xen: Fix event channel callback via INTX/GSI")
I reworked the triggering of xenbus_probe().

I tried to simplify things by taking out the workqueue based startup
triggered from wake_waiting(); the somewhat poorly named xenbus IRQ
handler.

I missed the fact that in the XS_LOCAL case (Dom0 starting its own
xenstored or xenstore-stubdom, which happens after the kernel is booted
completely), that IRQ-based trigger is still actually needed.

So... put it back, except more cleanly. By just spawning a xenbus_probe
thread which waits on xb_waitq and runs the probe the first time it
gets woken, just as the workqueue-based hack did.

This is actually a nicer approach for *all* the back ends with different
interrupt methods, and we can switch them all over to that without the
complex conditions for when to trigger it. But not in -rc6. This is
the minimal fix for the regression, although it's a step in the right
direction instead of doing a partial revert and actually putting the
workqueue back. It's also simpler than the workqueue.

Fixes: 3499ba8198 ("xen: Fix event channel callback via INTX/GSI")
Reported-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/4c9af052a6e0f6485d1de43f2c38b1461996db99.camel@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
2021-01-27 08:59:52 +01:00
..
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xenbus.h xen: Fix event channel callback via INTX/GSI 2021-01-13 16:12:00 +01:00
xenbus_client.c xen/xenbus: Add 'will_handle' callback support in xenbus_watch_path() 2020-12-14 10:04:18 +01:00
xenbus_comms.c xen: Fix event channel callback via INTX/GSI 2021-01-13 16:12:00 +01:00
xenbus_dev_backend.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xenbus_dev_frontend.c xen/xenbus: fix self-deadlock after killing user process 2019-10-02 16:40:11 -04:00
xenbus_probe.c xen: Fix XenStore initialisation for XS_LOCAL 2021-01-27 08:59:52 +01:00
xenbus_probe_backend.c xenbus/xenbus_backend: Disallow pending watch messages 2020-12-14 10:08:40 +01:00
xenbus_probe_frontend.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
xenbus_xs.c xen/xenbus: Count pending messages for each watch 2020-12-14 10:07:13 +01:00