Missing "@" in include/linux/wait.h cause "make htmldocs" failed
with following warning messages.
Warning(/home/iida/Repo/linux-next//include/linux/wait.h:304):
No description found for parameter 'cmd1'
Warning(/home/iida/Repo/linux-next//include/linux/wait.h:304):
No description found for parameter 'cmd2'
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Add a new API wait_event_cmd(). It's a variant of wait_even() with two
commands executed. One is executed before sleep, another after sleep.
Modified to match use wait.h approach based on suggestion by
Peter Zijlstra <peterz@infradead.org> - neilb
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
__wait_event_interruptible_lock_irq_timeout() needs the timeout
parameter passed instead of "ret".
This magically compiled since the only user has a local ret
variable. Luckily we got a build warning:
CC drivers/s390/scsi/zfcp_qdio.o
drivers/s390/scsi/zfcp_qdio.c: In function 'zfcp_qdio_sbal_get':
include/linux/wait.h:780:15: warning: 'ret' may be used uninitialized
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20131031114814.GB5551@osiris
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add the new helper, prepare_to_wait_event() which should only be used
by ___wait_event().
prepare_to_wait_event() returns -ERESTARTSYS if signal_pending_state()
is true, otherwise it does prepare_to_wait/exclusive. This allows to
uninline the signal-pending checks in wait_event*() macros.
Also, it can initialize wait->private/func. We do not care if they were
already initialized, the values are the same. This also shaves a couple
of insns from the inlined code.
This obviously makes prepare_*() path a little bit slower, but we are
likely going to sleep anyway, so I think it makes sense to shrink .text:
text data bss dec hex filename
===================================================
before: 5126092 2959248 10117120 18202460 115bf5c vmlinux
after: 5124618 2955152 10117120 18196890 115a99a vmlinux
on my build.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131007161824.GA29757@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 4c663cfc ("wait: fix false timeouts when using
wait_event_timeout()") introduced the additional condition checks
after a timeout but only in the "slow" __wait*() paths.
wait_event_timeout(wq, CONDITION, 0) still returns 0 if CONDITION
is already true and we do not call __wait*().
Now that we have ___wait_cond_timeout() we can use it instead to
ensure that __ret will be properly updated.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131007183106.GA10973@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There's far too much duplication in the __wait_event macros; in order
to fix this introduce ___wait_event() a macro with the capability to
replace most other macros.
With the previous patches changing the various __wait_event*()
implementations to be more uniform; we can now collapse the lot
without also changing generated code.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131002092528.181897111@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit 4c663cf ("wait: fix false timeouts when using
wait_event_timeout()") introduced an additional condition check after
a timeout but there's a few issues;
- it forgot one site
- it put the check after the main loop; not at the actual timeout
check.
Cure both; by wrapping the condition (as suggested by Oleg), this
avoids double evaluation of 'condition' which could be quite big.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131002092528.028892896@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There's two patterns to check signals in the __wait_event*() macros:
if (!signal_pending(current)) {
schedule();
continue;
}
ret = -ERESTARTSYS;
break;
And the more natural:
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
schedule();
Change them all into the latter form.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131002092527.956416254@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds wait_event_interruptible_lock_irq_timeout(), which is a
straight-forward descendant of wait_event_interruptible_timeout() and
wait_event_interruptible_lock_irq().
The zfcp driver used to call wait_event_interruptible_timeout()
in combination with some intricate and error-prone locking. Using
wait_event_interruptible_lock_irq_timeout() as a replacement
nicely cleans up that locking.
This rework removes a situation that resulted in a locking imbalance
in zfcp_qdio_sbal_get():
BUG: workqueue leaked lock or atomic: events/1/0xffffff00/10
last function: zfcp_fc_wka_port_offline+0x0/0xa0 [zfcp]
It was introduced by commit c2af7545aa
"[SCSI] zfcp: Do not wait for SBALs on stopped queue", which had a new
code path related to ZFCP_STATUS_ADAPTER_QDIOUP that took an early exit
without a required lock being held. The problem occured when a
special, non-SCSI I/O request was being submitted in process context,
when the adapter's queues had been torn down. In this case the bug
surfaced when the Fibre Channel port connection for a well-known address
was closed during a concurrent adapter shut-down procedure, which is a
rare constellation.
This patch also fixes these warnings from the sparse tool (make C=1):
drivers/s390/scsi/zfcp_qdio.c:224:12: warning: context imbalance in
'zfcp_qdio_sbal_check' - wrong count at exit
drivers/s390/scsi/zfcp_qdio.c:244:5: warning: context imbalance in
'zfcp_qdio_sbal_get' - unexpected unlock
Last but not least, we get rid of that crappy lock-unlock-lock
sequence at the beginning of the critical section.
It is okay to call zfcp_erp_adapter_reopen() with req_q_lock held.
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org #2.6.35+
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Pull FS-Cache updates from David Howells:
"This contains a number of fixes for various FS-Cache issues plus some
cleanups. The commits are, in order:
1) Provide a system wait_on_atomic_t() and wake_up_atomic_t() sharing
the bit-wait table (enhancement for #8).
2) Don't put spin_lock() in a while-condition as spin_lock() may have
a do {} while(0) wrapper (cleanup).
3) Symbolically name i_mutex lock classes rather than using numbers
in CacheFiles (cleanup).
4) Don't sleep in page release if __GFP_FS is not set (deadlock vs
ext4).
5) Uninline fscache_object_init() (cleanup for #7).
6) Wrap checks on object state (cleanup for #7).
7) Simplify the object state machine by separating work states from
wait states.
8) Simplify cookie retention by objects (NULL pointer deref fix).
9) Remove unused list_to_page() macro (cleanup).
10) Make the remaining-pages counter in the retrieval op atomic
(assertion failure fix).
11) Don't use spin_is_locked() in assertions (assertion failure fix)"
* tag 'fscache-20130702' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
FS-Cache: Don't use spin_is_locked() in assertions
FS-Cache: The retrieval remaining-pages counter needs to be atomic_t
cachefiles: remove unused macro list_to_page()
FS-Cache: Simplify cookie retention for fscache_objects, fixing oops
FS-Cache: Fix object state machine to have separate work and wait states
FS-Cache: Wrap checks on object state
FS-Cache: Uninline fscache_object_init()
FS-Cache: Don't sleep in page release if __GFP_FS is not set
CacheFiles: name i_mutex lock class explicitly
fs/fscache: remove spin_lock() from the condition in while()
Add wait_on_atomic_t() and wake_up_atomic_t()
Many callers of the wait_event_timeout() and
wait_event_interruptible_timeout() expect that the return value will be
positive if the specified condition becomes true before the timeout
elapses. However, at the moment this isn't guaranteed. If the wake-up
handler is delayed enough, the time remaining until timeout will be
calculated as 0 - and passed back as a return value - even if the
condition became true before the timeout has passed.
Fix this by returning at least 1 if the condition becomes true. This
semantic is in line with what wait_for_condition_timeout() does; see
commit bb10ed09 ("sched: fix wait_for_completion_timeout() spurious
failure under heavy load").
Daniel said "We have 3 instances of this bug in drm/i915. One case even
where we switch between the interruptible and not interruptible
wait_event_timeout variants, foolishly presuming they have the same
semantics. I very much like this."
One such bug is reported at
https://bugs.freedesktop.org/show_bug.cgi?id=64133
Signed-off-by: Imre Deak <imre.deak@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Lukas Czerner <lczerner@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
