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2014-01-28rwsem: add rwsem_is_contendedJosef Bacik1-0/+11
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>
2013-03-23Revert "rw_semaphore: remove up/down_read_non_owner"Kent Overstreet1-0/+10
This reverts commit 11b80f459adaf91a712f95e7734a17655a36bf30. 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>
2013-01-16lockdep, rwsem: fix down_write_nest_lock() if !CONFIG_DEBUG_LOCK_ALLOCJiri Kosina1-1/+1
Commit 1b963c81b145 ("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>
2013-01-11lockdep, rwsem: provide down_write_nest_lock()Jiri Kosina1-0/+9
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>
2012-03-28Remove all #inclusions of asm/system.hDavid Howells1-1/+0
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>
2011-09-13locking, rwsem: Annotate inner lock as rawThomas Gleixner1-4/+6
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>
2011-07-26atomic: use <linux/atomic.h>Arun Sharma1-1/+1
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>
2011-07-20rw_semaphore: remove up/down_read_non_ownerChristoph Hellwig1-10/+0
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>
2011-01-27rwsem: Remove redundant asmregparm annotationThomas Gleixner1-4/+4
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>
2011-01-27rwsem: Move duplicate function prototypes to linux/rwsem.hThomas Gleixner1-0/+5
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>
2011-01-27rwsem: Unify the duplicate rwsem_is_locked() inlinesThomas Gleixner1-0/+7
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>
2011-01-27rwsem: Move duplicate init macros and functions to linux/rwsem.hThomas Gleixner1-0/+25
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>
2011-01-27rwsem: Move duplicate struct rwsem declaration to linux/rwsem.hThomas Gleixner1-1/+12
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>
2011-01-27rwsem: Cleanup includesThomas Gleixner1-0/+3
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>
2008-04-30Remove "#ifdef __KERNEL__" checks from unexported headersRobert P. J. Day1-3/+0
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>
2006-07-10[PATCH] lockdep: add more rwsem.h documentationIngo Molnar1-2/+15
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>
2006-07-03[PATCH] lockdep: prove rwsem locking correctnessIngo Molnar1-34/+25
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[PATCH] lockdep: clean up rwsemsIngo Molnar1-24/+0
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>
2006-04-26Don't include linux/config.h from anywhere else in include/David Woodhouse1-1/+0
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds1-0/+115
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!