Commit Graph

20 Commits

Author SHA1 Message Date
Josef Bacik 4a444b1f06 rwsem: add rwsem_is_contended
Btrfs needs a simple way to know if it needs to let go of it's read lock on a
rwsem.  Introduce rwsem_is_contended to check to see if there are any waiters on
this rwsem currently.  This is just a hueristic, it is meant to be light and not
100% accurate and called by somebody already holding on to the rwsem in either
read or write.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
2014-01-28 13:20:09 -08:00
Kent Overstreet 84759c6d18 Revert "rw_semaphore: remove up/down_read_non_owner"
This reverts commit 11b80f459a.

Bcache needs rw semaphores for cache coherency in writeback mode -
writes have to take a read lock on a per cache device rw sem, and
release it when the bio completes.

But since this is for bios it's naturally not in the context of the
process that originally took the lock.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Christoph Hellwig <hch@infradead.org>
CC: David Howells <dhowells@redhat.com>
2013-03-23 15:53:52 -07:00
Jiri Kosina e65b9ad222 lockdep, rwsem: fix down_write_nest_lock() if !CONFIG_DEBUG_LOCK_ALLOC
Commit 1b963c81b1 ("lockdep, rwsem: provide down_write_nest_lock()")
contains a bug in a codepath when CONFIG_DEBUG_LOCK_ALLOC is disabled,
which causes down_read() to be called instead of down_write() by mistake
on such configurations.  Fix that.

Reported-and-tested-by: Andrew Clayton <andrew@digital-domain.net>
Reported-and-tested-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-16 12:13:20 -08:00
Jiri Kosina 1b963c81b1 lockdep, rwsem: provide down_write_nest_lock()
down_write_nest_lock() provides a means to annotate locking scenario
where an outer lock is guaranteed to serialize the order nested locks
are being acquired.

This is analogoue to already existing mutex_lock_nest_lock() and
spin_lock_nest_lock().

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-11 14:54:55 -08:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
Thomas Gleixner ddb6c9b58a locking, rwsem: Annotate inner lock as raw
There is no reason to allow the lock protecting rwsems (the
ownerless variant) to be preemptible on -rt. Convert it to raw.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-13 11:11:59 +02:00
Arun Sharma 60063497a9 atomic: use <linux/atomic.h>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26 16:49:47 -07:00
Christoph Hellwig 11b80f459a rw_semaphore: remove up/down_read_non_owner
Now that the last users is gone these can be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:47 -04:00
Thomas Gleixner d123375425 rwsem: Remove redundant asmregparm annotation
Peter Zijlstra pointed out, that the only user of asmregparm (x86) is
compiling the kernel already with -mregparm=3. So the annotation of
the rwsem functions is redundant. Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <alpine.LFD.2.00.1101262130450.31804@localhost6.localdomain6>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27 12:30:40 +01:00
Thomas Gleixner aac72277fd rwsem: Move duplicate function prototypes to linux/rwsem.h
All architecture specific rwsem headers carry the same function
prototypes. Just x86 adds asmregparm, which is an empty define on all
other architectures. S390 has a stale rwsem_downgrade_write()
prototype.

Remove the duplicates and add the prototypes to linux/rwsem.h

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Henderson <rth@twiddle.net>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.970840140@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27 12:30:39 +01:00
Thomas Gleixner 41e5887fa3 rwsem: Unify the duplicate rwsem_is_locked() inlines
Instead of having the same implementation in each architecture, move
it to linux/rwsem.h and remove the duplicates. It's unlikely that an
arch will ever implement something different, but we can deal with
that when it happens.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.876773757@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27 12:30:39 +01:00
Thomas Gleixner 12249b3441 rwsem: Move duplicate init macros and functions to linux/rwsem.h
The rwsem initializers and related macros and functions are mostly the
same. Some of them lack the lockdep initializer, but having it in
place does not matter for architectures which do not support lockdep.

powerpc, sparc, x86: No functional change

sh, s390: Removes the duplicate init_rwsem (inline and #define)

alpha, ia64, xtensa: Use the lockdep capable init function in
       	     	     lib/rwsem.c which is just uninlining the init
       	     	     function for the LOCKDEP=n case

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.771812729@linutronix.de>
2011-01-27 12:30:39 +01:00
Thomas Gleixner 1c8ed640d9 rwsem: Move duplicate struct rwsem declaration to linux/rwsem.h
The difference between these declarations is the data type of the
count member and the lack of lockdep in some architectures/

long is equivivalent to signed long and the #ifdef guarded dep_map
member does not hurt anyone.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.679641914@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27 12:30:39 +01:00
Thomas Gleixner c16a87ce06 rwsem: Cleanup includes
All rwsem implementations include the same headers. Include them from
include/linux/rwsem.h

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Matt Turner <mattst88@gmail.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Acked-by: David Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
LKML-Reference: <20110126195833.483520950@linutronix.de>
2011-01-27 12:30:38 +01:00
Robert P. J. Day 735643ee6c Remove "#ifdef __KERNEL__" checks from unexported headers
Remove the "#ifdef __KERNEL__" tests from unexported header files in
linux/include whose entire contents are wrapped in that preprocessor
test.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:54 -07:00
Ingo Molnar 5fca80e8b4 [PATCH] lockdep: add more rwsem.h documentation
Add more documentation to rwsem.h.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: David Howells <dhowells@redhat.com>
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 4ea2176dfa [PATCH] lockdep: prove rwsem locking correctness
Use the lock validator framework to prove rwsem locking correctness.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:04 -07:00
Ingo Molnar c4e05116a2 [PATCH] lockdep: clean up rwsems
Clean up rwsems.

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 15:27:01 -07:00
David Woodhouse 62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
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