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25 commits

Author SHA1 Message Date
Ingo Molnar
527187d285 locking/lockdep: Remove cross-release leftovers
There's two cross-release leftover facilities:

 - the crossrelease_hist_*() irq-tracing callbacks (NOPs currently)
 - the complete_release_commit() callback (NOP as well)

Remove them.

Cc: David Sterba <dsterba@suse.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-08 17:30:45 +01:00
Ingo Molnar
e966eaeeb6 locking/lockdep: Remove the cross-release locking checks
This code (CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y),
while it found a number of old bugs initially, was also causing too many
false positives that caused people to disable lockdep - which is arguably
a worse overall outcome.

If we disable cross-release by default but keep the code upstream then
in practice the most likely outcome is that we'll allow the situation
to degrade gradually, by allowing entropy to introduce more and more
false positives, until it overwhelms maintenance capacity.

Another bad side effect was that people were trying to work around
the false positives by uglifying/complicating unrelated code. There's
a marked difference between annotating locking operations and
uglifying good code just due to bad lock debugging code ...

This gradual decrease in quality happened to a number of debugging
facilities in the kernel, and lockdep is pretty complex already,
so we cannot risk this outcome.

Either cross-release checking can be done right with no false positives,
or it should not be included in the upstream kernel.

( Note that it might make sense to maintain it out of tree and go through
  the false positives every now and then and see whether new bugs were
  introduced. )

Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-12-12 12:38:51 +01:00
Ingo Molnar
8c5db92a70 Merge branch 'linus' into locking/core, to resolve conflicts
Conflicts:
	include/linux/compiler-clang.h
	include/linux/compiler-gcc.h
	include/linux/compiler-intel.h
	include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:32:44 +01:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Byungchul Park
a7967bc315 sched/completions: Add support for initializing completions with lockdep_map
Sometimes we want to initialize completions with sparate lockdep maps
to assign lock classes as desired. For example, the workqueue code
needs to directly manage lockdep maps, since only the code is aware of
how to classify lockdep maps properly.

Provide additional macros initializing completions in that way.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: darrick.wong@oracle.com
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-8-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 12:19:03 +02:00
Byungchul Park
24208435e3 locking/lockdep, sched/completions: Change the prefix of lock name for completion variables
CONFIG_LOCKDEP_COMPLETIONS uses "(complete)" as a prefix of lock name
for completion variable.

However, what we should use here is a noun - so use "(completion)" instead.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: amir73il@gmail.com
Cc: axboe@kernel.dk
Cc: darrick.wong@oracle.com
Cc: david@fromorbit.com
Cc: hch@infradead.org
Cc: idryomov@gmail.com
Cc: johan@kernel.org
Cc: johannes.berg@intel.com
Cc: kernel-team@lge.com
Cc: linux-block@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1508921765-15396-4-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-25 12:19:00 +02:00
Boqun Feng
ec81048cc3 sched/completion: Avoid unnecessary stack allocation for COMPLETION_INITIALIZER_ONSTACK()
In theory, COMPLETION_INITIALIZER_ONSTACK() should never affect the
stack allocation of the caller. However, on some compilers, a temporary
structure was allocated for the return value of
COMPLETION_INITIALIZER_ONSTACK().

For example in write_journal() with LOCKDEP_COMPLETIONS=y (GCC is 7.1.1):

	io_comp.comp = COMPLETION_INITIALIZER_ONSTACK(io_comp.comp);
	    2462:       e8 00 00 00 00          callq  2467 <write_journal+0x47>
	    2467:       48 8d 85 80 fd ff ff    lea    -0x280(%rbp),%rax
	    246e:       48 c7 c6 00 00 00 00    mov    $0x0,%rsi
	    2475:       48 c7 c2 00 00 00 00    mov    $0x0,%rdx
		x->done = 0;
	    247c:       c7 85 90 fd ff ff 00    movl   $0x0,-0x270(%rbp)
	    2483:       00 00 00
		init_waitqueue_head(&x->wait);
	    2486:       48 8d 78 18             lea    0x18(%rax),%rdi
	    248a:       e8 00 00 00 00          callq  248f <write_journal+0x6f>
		if (commit_start + commit_sections <= ic->journal_sections) {
	    248f:       41 8b 87 a8 00 00 00    mov    0xa8(%r15),%eax
		io_comp.comp = COMPLETION_INITIALIZER_ONSTACK(io_comp.comp);
	    2496:       48 8d bd e8 f9 ff ff    lea    -0x618(%rbp),%rdi
	    249d:       48 8d b5 90 fd ff ff    lea    -0x270(%rbp),%rsi
	    24a4:       b9 17 00 00 00          mov    $0x17,%ecx
	    24a9:       f3 48 a5                rep movsq %ds:(%rsi),%es:(%rdi)
		if (commit_start + commit_sections <= ic->journal_sections) {
	    24ac:       41 39 c6                cmp    %eax,%r14d
		io_comp.comp = COMPLETION_INITIALIZER_ONSTACK(io_comp.comp);
	    24af:       48 8d bd 90 fd ff ff    lea    -0x270(%rbp),%rdi
	    24b6:       48 8d b5 e8 f9 ff ff    lea    -0x618(%rbp),%rsi
	    24bd:       b9 17 00 00 00          mov    $0x17,%ecx
	    24c2:       f3 48 a5                rep movsq %ds:(%rsi),%es:(%rdi)

We can obviously see the temporary structure allocated, and the compiler
also does two meaningless memcpy with "rep movsq".

And according to:

	https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement-Exprs

The return value of a statement expression is returned by value, so the
temporary variable is created in COMPLETION_INITIALIZER_ONSTACK(), and
that's why the temporary structures are allocted.

To fix this, make the brace block in COMPLETION_INITIALIZER_ONSTACK()
return a pointer and dereference it outside the block rather than return
the whole structure, in this way, we are able to teach the compiler not
to do the unnecessary stack allocation.

This could also reduce the stack size even if !LOCKDEP, for example in
write_journal(), compiled with gcc 7.1.1, the result of command:

	 objdump -d drivers/md/dm-integrity.o | ./scripts/checkstack.pl x86

before:

	0x0000246a write_journal [dm-integrity.o]:              696

after:

	0x00002b7a write_journal [dm-integrity.o]:              296

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/20170823152542.5150-3-boqun.feng@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-29 15:14:38 +02:00
Byungchul Park
ea3f2c0fdf locking/lockdep: Rename CONFIG_LOCKDEP_COMPLETE to CONFIG_LOCKDEP_COMPLETIONS
'complete' is an adjective and LOCKDEP_COMPLETE sounds like 'lockdep is complete',
so pick a better name that uses a noun.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/1502960261-16206-3-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17 11:38:55 +02:00
Byungchul Park
cd8084f91c locking/lockdep: Apply crossrelease to completions
Although wait_for_completion() and its family can cause deadlock, the
lock correctness validator could not be applied to them until now,
because things like complete() are usually called in a different context
from the waiting context, which violates lockdep's assumption.

Thanks to CONFIG_LOCKDEP_CROSSRELEASE, we can now apply the lockdep
detector to those completion operations. Applied it.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/1502089981-21272-10-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10 12:29:10 +02:00
Wolfram Sang
62026aedaa sched: remove INIT_COMPLETION
All users are converted over to reinit_completion(). Remove the old
macro now.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:21 +09:00
Wolfram Sang
c32f74ab28 sched: replace INIT_COMPLETION with reinit_completion
For the casual device driver writer, it is hard to remember when to use
init_completion (to init a completion structure) or INIT_COMPLETION (to
*reinit* a completion structure).  Furthermore, while all other
completion functions exepct a pointer as a parameter, INIT_COMPLETION
does not.  To make it easier to remember which function to use and to
make code more readable, introduce a new inline function with the proper
name and consistent argument type.  Update the kernel-doc for
init_completion while we are here.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-15 09:32:21 +09:00
Peter Zijlstra
b8a216269e sched: Move completion code from core.c to completion.c
Completions already have their own header file: linux/completion.h
Move the implementation out of kernel/sched/core.c and into its own
file: kernel/sched/completion.c.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-x2y49rmxu5dljt66ai2lcfuw@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06 07:49:19 +01:00
Viresh Kumar
0a0fca9d83 sched: Rename sched.c as sched/core.c in comments and Documentation
Most of the stuff from kernel/sched.c was moved to kernel/sched/core.c long time
back and the comments/Documentation never got updated.

I figured it out when I was going through sched-domains.txt and so thought of
fixing it globally.

I haven't crossed check if the stuff that is referenced in sched/core.c by all
these files is still present and hasn't changed as that wasn't the motive behind
this patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/cdff76a265326ab8d71922a1db5be599f20aad45.1370329560.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-19 12:58:42 +02:00
Vladimir Davydov
686855f5d8 sched: add wait_for_completion_io[_timeout]
The only difference between wait_for_completion[_timeout]() and
wait_for_completion_io[_timeout]() is that the latter calls
io_schedule_timeout() instead of schedule_timeout() so that the caller
is accounted as waiting for IO, not just sleeping.

These functions can be used for correct iowait time accounting when the
completion struct is actually used for waiting for IO (e.g. completion
of a bio request in the block layer).

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-02-15 16:45:06 +01:00
NeilBrown
6bf4123760 sched: Change wait_for_completion_*_timeout() to return a signed long
wait_for_completion_*_timeout() can return:

   0: if the wait timed out
 -ve: if the wait was interrupted
 +ve: if the completion was completed.

As they currently return an 'unsigned long', the last two cases
are not easily distinguished which can easily result in buggy
code, as is the case for the recently added
wait_for_completion_interruptible_timeout() call in
net/sunrpc/cache.c

So change them both to return 'long'.  As MAX_SCHEDULE_TIMEOUT
is LONG_MAX, a large +ve return value should never overflow.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: J.  Bruce Fields <bfields@fieldses.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110105125016.64ccab0e@notabene.brown>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-05 14:15:50 +01:00
Randy Dunlap
ee2f154a59 docbook: add more wait/wake/completion to device-drivers docbook
Add more wait, wake, and completion interfaces to the device-drivers
docbook.

Fix kernel-doc notation in the added files.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-26 17:32:41 -07:00
Sage Weil
0aa12fb439 sched: add wait_for_completion_killable_timeout
Add missing _killable_timeout variant for wait_for_completion that will
return when a timeout expires or the task is killed.

CC: Ingo Molnar <mingo@elte.hu>
CC: Andreas Herrmann <andreas.herrmann3@amd.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-29 09:12:30 -07:00
Kevin Diggs
65eb3dc609 sched: add kernel doc for the completion, fix kernel-doc-nano-HOWTO.txt
This patch adds kernel doc for the completion feature.

An error in the split-man.pl PERL snippet in kernel-doc-nano-HOWTO.txt is
also fixed.

Signed-off-by: Kevin Diggs <kevdig@hypersurf.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-26 10:26:54 +02:00
Dave Chinner
be4de35263 completions: uninline try_wait_for_completion and completion_done
m68k fails to build with these functions inlined in completion.h.  Move
them out of line into sched.c and export them to avoid this problem.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-15 08:35:44 -07:00
David Chinner
39d2f1ab2a [XFS] extend completions to provide XFS object flush requirements
XFS object flushing doesn't quite match existing completion semantics.  It
mixed exclusive access with completion.  That is, we need to mark an object as
being flushed before flushing it to disk, and then block any other attempt to
flush it until the completion occurs.  We do this but adding an extra count to
the completion before we start using them.  However, we still need to
determine if there is a completion in progress, and allow no-blocking attempts
fo completions to decrement the count.

To do this we introduce:

int try_wait_for_completion(struct completion *x)
	returns a failure status if done == 0, otherwise decrements done
	to zero and returns a "started" status. This is provided
	to allow counted completions to begin safely while holding
	object locks in inverted order.

int completion_done(struct completion *x)
	returns 1 if there is no waiter, 0 if there is a waiter
	(i.e. a completion in progress).

This replaces the use of semaphores for providing this exclusion
and completion mechanism.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31816a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
2008-08-13 16:40:43 +10:00
Matthew Wilcox
009e577e07 Add wait_for_completion_killable
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-12-06 17:40:19 -05:00
Ingo Molnar
b15136e949 sched: fix fastcall mismatch in completion APIs
Jeff Dike noticed that wait_for_completion_interruptible()'s prototype
had a mismatched fastcall.

Fix this by removing the fastcall attributes from all the completion APIs.

Found-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-24 18:23:48 +02:00
Ingo Molnar
f86bf9b7bc [PATCH] lockdep: clean up completion initializer in smpboot.c
Clean up lockdep on-stack-completion initializer.  (This also removes the
dependency on waitqueue_lock_key.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:14 -07:00
Ingo Molnar
8b3db9c542 [PATCH] lockdep: add DECLARE_COMPLETION_ONSTACK() API
lockdep needs to have the waitqueue lock initialized for on-stack waitqueues
implicitly initialized by DECLARE_COMPLETION().  Introduce the API.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:00 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00