Commit-ID: 664b4e24c6145830885e854195376351b0eb3eee Gitweb: http://git.kernel.org/tip/664b4e24c6145830885e854195376351b0eb3eee Author: Michal Hocko <mho...@suse.com> AuthorDate: Thu, 7 Apr 2016 17:12:30 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 13 Apr 2016 10:42:22 +0200
locking/rwsem, x86: Provide __down_write_killable() which uses the same fast path as __down_write() except it falls back to call_rwsem_down_write_failed_killable() slow path and return -EINTR if killed. To prevent from code duplication extract the skeleton of __down_write() into a helper macro which just takes the semaphore and the slow path function to be called. Signed-off-by: Michal Hocko <mho...@suse.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Chris Zankel <ch...@zankel.net> Cc: David S. Miller <da...@davemloft.net> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Max Filippov <jcmvb...@gmail.com> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Signed-off-by: Davidlohr Bueso <dbu...@suse.de> Cc: Signed-off-by: Jason Low <jason.l...@hp.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Tony Luck <tony.l...@intel.com> Cc: linux-al...@vger.kernel.org Cc: linux-a...@vger.kernel.org Cc: linux-i...@vger.kernel.org Cc: linux-s...@vger.kernel.org Cc: linux...@vger.kernel.org Cc: linux-xte...@linux-xtensa.org Cc: sparcli...@vger.kernel.org Link: http://lkml.kernel.org/r/1460041951-22347-11-git-send-email-mho...@kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/include/asm/rwsem.h | 41 ++++++++++++++++++++++++++++------------- arch/x86/lib/rwsem.S | 8 ++++++++ 2 files changed, 36 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index 4a8292a..d759c5f 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -99,21 +99,36 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) /* * lock for writing */ +#define ____down_write(sem, slow_path) \ +({ \ + long tmp; \ + struct rw_semaphore* ret = sem; \ + asm volatile("# beginning down_write\n\t" \ + LOCK_PREFIX " xadd %1,(%2)\n\t" \ + /* adds 0xffff0001, returns the old value */ \ + " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \ + /* was the active mask 0 before? */\ + " jz 1f\n" \ + " call " slow_path "\n" \ + "1:\n" \ + "# ending down_write" \ + : "+m" (sem->count), "=d" (tmp), "+a" (ret) \ + : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \ + : "memory", "cc"); \ + ret; \ +}) + static inline void __down_write(struct rw_semaphore *sem) { - long tmp; - asm volatile("# beginning down_write\n\t" - LOCK_PREFIX " xadd %1,(%2)\n\t" - /* adds 0xffff0001, returns the old value */ - " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" - /* was the active mask 0 before? */ - " jz 1f\n" - " call call_rwsem_down_write_failed\n" - "1:\n" - "# ending down_write" - : "+m" (sem->count), "=d" (tmp) - : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) - : "memory", "cc"); + ____down_write(sem, "call_rwsem_down_write_failed"); +} + +static inline int __down_write_killable(struct rw_semaphore *sem) +{ + if (IS_ERR(____down_write(sem, "call_rwsem_down_write_failed_killable"))) + return -EINTR; + + return 0; } /* diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S index be110ef..4534a7e 100644 --- a/arch/x86/lib/rwsem.S +++ b/arch/x86/lib/rwsem.S @@ -106,6 +106,14 @@ ENTRY(call_rwsem_down_write_failed) ret ENDPROC(call_rwsem_down_write_failed) +ENTRY(call_rwsem_down_write_failed_killable) + save_common_regs + movq %rax,%rdi + call rwsem_down_write_failed_killable + restore_common_regs + ret +ENDPROC(call_rwsem_down_write_failed_killable) + ENTRY(call_rwsem_wake) FRAME_BEGIN /* do nothing if still outstanding active readers */
