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2016-04-13locking/rwsem: Introduce basis for down_write_killable()Michal Hocko1-0/+12
Introduce a generic implementation necessary for down_write_killable(). This is a trivial extension of the already existing down_write() call which can be interrupted by SIGKILL. This patch doesn't provide down_write_killable() yet because arches have to provide the necessary pieces before. rwsem_down_write_failed() which is a generic slow path for the write lock is extended to take a task state and renamed to __rwsem_down_write_failed_common(). The return value is either a valid semaphore pointer or ERR_PTR(-EINTR). rwsem_down_write_failed_killable() is exported as a new way to wait for the lock and be killable. For rwsem-spinlock implementation the current __down_write() it updated in a similar way as __rwsem_down_write_failed_common() except it doesn't need new exports just visible __down_write_killable(). Architectures which are not using the generic rwsem implementation are supposed to provide their __down_write_killable() implementation and use rwsem_down_write_failed_killable() for the slow path. Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Zankel <chris@zankel.net> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Signed-off-by: Jason Low <jason.low2@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-alpha@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/1460041951-22347-7-git-send-email-mhocko@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-13locking/rwsem: Get rid of __down_write_nested()Michal Hocko1-6/+1
This is no longer used anywhere and all callers (__down_write()) use 0 as a subclass. Ditch __down_write_nested() to make the code easier to follow. This shouldn't introduce any functional change. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Zankel <chris@zankel.net> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Signed-off-by: Jason Low <jason.low2@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-alpha@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/1460041951-22347-2-git-send-email-mhocko@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-06locking/rwsem: Use acquire/release semanticsDavidlohr Bueso1-7/+14
As of 654672d4ba1 (locking/atomics: Add _{acquire|release|relaxed}() variants of some atomic operations) and 6d79ef2d30e (locking, asm-generic: Add _{relaxed|acquire|release}() variants for 'atomic_long_t'), weakly ordered archs can benefit from more relaxed use of barriers when locking and unlocking, instead of regular full barrier semantics. While currently only arm64 supports such optimizations, updating corresponding locking primitives serves for other archs to immediately benefit as well, once the necessary machinery is implemented of course. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E.McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1443643395-17016-6-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-14asm-generic: rwsem: de-PPCify rwsem.hWill Deacon1-5/+5
asm-generic/rwsem.h used to live under arch/powerpc. During its liberation to common code, a few references to its former home where preserved, in particular the definition of RWSEM_ACTIVE_MASK is predicated on CONFIG_PPC64. This patch updates the ifdefs and comments to architecturally neutral versions. Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Richard Kuo <rkuo@codeaurora.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2011-11-01Hexagon: Add locking types and functionsRichard Kuo1-0/+132
Signed-off-by: Richard Kuo <rkuo@codeaurora.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>