An iucv deadlock may occur, where one CPU is spinning on the
iucv_table_lock for iucv_tasklet_fn(), while another CPU is holding
the iucv_table_lock for an iucv_path_connect() and is waiting for
the first CPU in an smp_call_function.
Solution: replace spin_lock in iucv_tasklet_fn by spin_trylock and
reschedule tasklet in case of non-granted lock.
Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Acked-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress. This
patch introduces such notifications and causes them to be used during
suspend and resume transitions. It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).
[oleg@tv-sign.ru: cleanups]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add missing section annotations and found and fixed some
Coding Style issues.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com>
Calling smp_call_function can lead to a deadlock if it is called
from tasklet context.
Fixing this deadlock requires to move the smp_call_function from the
tasklet context to a work queue. To do that queue the path pending
interrupts to a separate list and move the path cleanup out of
iucv_path_sever to iucv_path_connect and iucv_path_pending.
This creates a new requirement for iucv_path_connect: it may not be
called from tasklet context anymore.
Also fixed compile problem for CONFIG_HOTPLUG_CPU=n and
another one when walking the cpu_online mask. When doing this,
we must disable cpu hotplug.
Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
CC [M] net/iucv/iucv.o
net/iucv/iucv.c: In function 'iucv_init':
net/iucv/iucv.c:1556: error: 'iucv_cpu_notifier' undeclared (first use in this function)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add rewritten IUCV base code to net/iucv.
Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
