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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-16 13:41:02 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-16 13:41:02 -0700 |
commit | 3469d261eac65912927dca13ee8f77c744ad7aa2 (patch) | |
tree | 09b25f80c065d52ee6e158c189ba44bb28bb76fc /arch | |
parent | 1c19b68a279c58d6da4379bf8b6d679a300a1daf (diff) | |
parent | 4544ba8c6b1743499cabb682897a469911845f15 (diff) | |
download | linux-stable-3469d261eac65912927dca13ee8f77c744ad7aa2.tar.gz linux-stable-3469d261eac65912927dca13ee8f77c744ad7aa2.tar.bz2 linux-stable-3469d261eac65912927dca13ee8f77c744ad7aa2.zip |
Merge branch 'locking-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull support for killable rwsems from Ingo Molnar:
"This, by Michal Hocko, implements down_write_killable().
The main usecase will be to update mm_sem usage sites to use this new
API, to allow the mm-reaper introduced in commit aac453635549 ("mm,
oom: introduce oom reaper") to tear down oom victim address spaces
asynchronously with minimum latencies and without deadlock worries"
[ The vfs will want it too as the inode lock is changed from a mutex to
a rwsem due to the parallel lookup and readdir updates ]
* 'locking-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Fix comment on register clobbering
locking/rwsem: Fix down_write_killable()
locking/rwsem, x86: Add frame annotation for call_rwsem_down_write_failed_killable()
locking/rwsem: Provide down_write_killable()
locking/rwsem, x86: Provide __down_write_killable()
locking/rwsem, s390: Provide __down_write_killable()
locking/rwsem, ia64: Provide __down_write_killable()
locking/rwsem, alpha: Provide __down_write_killable()
locking/rwsem: Introduce basis for down_write_killable()
locking/rwsem, sparc: Drop superfluous arch specific implementation
locking/rwsem, sh: Drop superfluous arch specific implementation
locking/rwsem, xtensa: Drop superfluous arch specific implementation
locking/rwsem: Drop explicit memory barriers
locking/rwsem: Get rid of __down_write_nested()
Diffstat (limited to 'arch')
-rw-r--r-- | arch/alpha/include/asm/rwsem.h | 18 | ||||
-rw-r--r-- | arch/ia64/include/asm/rwsem.h | 22 | ||||
-rw-r--r-- | arch/s390/include/asm/rwsem.h | 18 | ||||
-rw-r--r-- | arch/sh/include/asm/Kbuild | 1 | ||||
-rw-r--r-- | arch/sh/include/asm/rwsem.h | 132 | ||||
-rw-r--r-- | arch/sparc/include/asm/Kbuild | 1 | ||||
-rw-r--r-- | arch/sparc/include/asm/rwsem.h | 124 | ||||
-rw-r--r-- | arch/x86/include/asm/rwsem.h | 42 | ||||
-rw-r--r-- | arch/x86/lib/rwsem.S | 16 | ||||
-rw-r--r-- | arch/xtensa/include/asm/Kbuild | 1 | ||||
-rw-r--r-- | arch/xtensa/include/asm/rwsem.h | 131 |
11 files changed, 92 insertions, 414 deletions
diff --git a/arch/alpha/include/asm/rwsem.h b/arch/alpha/include/asm/rwsem.h index a83bbea62c67..0131a7058778 100644 --- a/arch/alpha/include/asm/rwsem.h +++ b/arch/alpha/include/asm/rwsem.h @@ -63,7 +63,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) return res >= 0 ? 1 : 0; } -static inline void __down_write(struct rw_semaphore *sem) +static inline long ___down_write(struct rw_semaphore *sem) { long oldcount; #ifndef CONFIG_SMP @@ -83,10 +83,24 @@ static inline void __down_write(struct rw_semaphore *sem) :"=&r" (oldcount), "=m" (sem->count), "=&r" (temp) :"Ir" (RWSEM_ACTIVE_WRITE_BIAS), "m" (sem->count) : "memory"); #endif - if (unlikely(oldcount)) + return oldcount; +} + +static inline void __down_write(struct rw_semaphore *sem) +{ + if (unlikely(___down_write(sem))) rwsem_down_write_failed(sem); } +static inline int __down_write_killable(struct rw_semaphore *sem) +{ + if (unlikely(___down_write(sem))) + if (IS_ERR(rwsem_down_write_failed_killable(sem))) + return -EINTR; + + return 0; +} + /* * trylock for writing -- returns 1 if successful, 0 if contention */ diff --git a/arch/ia64/include/asm/rwsem.h b/arch/ia64/include/asm/rwsem.h index ce112472bdd6..8b23e070b844 100644 --- a/arch/ia64/include/asm/rwsem.h +++ b/arch/ia64/include/asm/rwsem.h @@ -49,8 +49,8 @@ __down_read (struct rw_semaphore *sem) /* * lock for writing */ -static inline void -__down_write (struct rw_semaphore *sem) +static inline long +___down_write (struct rw_semaphore *sem) { long old, new; @@ -59,10 +59,26 @@ __down_write (struct rw_semaphore *sem) new = old + RWSEM_ACTIVE_WRITE_BIAS; } while (cmpxchg_acq(&sem->count, old, new) != old); - if (old != 0) + return old; +} + +static inline void +__down_write (struct rw_semaphore *sem) +{ + if (___down_write(sem)) rwsem_down_write_failed(sem); } +static inline int +__down_write_killable (struct rw_semaphore *sem) +{ + if (___down_write(sem)) + if (IS_ERR(rwsem_down_write_failed_killable(sem))) + return -EINTR; + + return 0; +} + /* * unlock after reading */ diff --git a/arch/s390/include/asm/rwsem.h b/arch/s390/include/asm/rwsem.h index fead491dfc28..c75e4471e618 100644 --- a/arch/s390/include/asm/rwsem.h +++ b/arch/s390/include/asm/rwsem.h @@ -90,7 +90,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) /* * lock for writing */ -static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) +static inline long ___down_write(struct rw_semaphore *sem) { signed long old, new, tmp; @@ -104,13 +104,23 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) : "=&d" (old), "=&d" (new), "=Q" (sem->count) : "Q" (sem->count), "m" (tmp) : "cc", "memory"); - if (old != 0) - rwsem_down_write_failed(sem); + + return old; } static inline void __down_write(struct rw_semaphore *sem) { - __down_write_nested(sem, 0); + if (___down_write(sem)) + rwsem_down_write_failed(sem); +} + +static inline int __down_write_killable(struct rw_semaphore *sem) +{ + if (___down_write(sem)) + if (IS_ERR(rwsem_down_write_failed_killable(sem))) + return -EINTR; + + return 0; } /* diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild index a319745a7b63..751c3373a92c 100644 --- a/arch/sh/include/asm/Kbuild +++ b/arch/sh/include/asm/Kbuild @@ -26,6 +26,7 @@ generic-y += percpu.h generic-y += poll.h generic-y += preempt.h generic-y += resource.h +generic-y += rwsem.h generic-y += sembuf.h generic-y += serial.h generic-y += shmbuf.h diff --git a/arch/sh/include/asm/rwsem.h b/arch/sh/include/asm/rwsem.h deleted file mode 100644 index edab57265293..000000000000 --- a/arch/sh/include/asm/rwsem.h +++ /dev/null @@ -1,132 +0,0 @@ -/* - * include/asm-sh/rwsem.h: R/W semaphores for SH using the stuff - * in lib/rwsem.c. - */ - -#ifndef _ASM_SH_RWSEM_H -#define _ASM_SH_RWSEM_H - -#ifndef _LINUX_RWSEM_H -#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" -#endif - -#ifdef __KERNEL__ - -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - if (atomic_inc_return((atomic_t *)(&sem->count)) > 0) - smp_wmb(); - else - rwsem_down_read_failed(sem); -} - -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - int tmp; - - while ((tmp = sem->count) >= 0) { - if (tmp == cmpxchg(&sem->count, tmp, - tmp + RWSEM_ACTIVE_READ_BIAS)) { - smp_wmb(); - return 1; - } - } - return 0; -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - int tmp; - - tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic_t *)(&sem->count)); - if (tmp == RWSEM_ACTIVE_WRITE_BIAS) - smp_wmb(); - else - rwsem_down_write_failed(sem); -} - -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - int tmp; - - tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - smp_wmb(); - return tmp == RWSEM_UNLOCKED_VALUE; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - int tmp; - - smp_wmb(); - tmp = atomic_dec_return((atomic_t *)(&sem->count)); - if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - smp_wmb(); - if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic_t *)(&sem->count)) < 0) - rwsem_wake(sem); -} - -/* - * implement atomic add functionality - */ -static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem) -{ - atomic_add(delta, (atomic_t *)(&sem->count)); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - int tmp; - - smp_wmb(); - tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count)); - if (tmp < 0) - rwsem_downgrade_wake(sem); -} - -static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) -{ - __down_write(sem); -} - -/* - * implement exchange and add functionality - */ -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) -{ - smp_mb(); - return atomic_add_return(delta, (atomic_t *)(&sem->count)); -} - -#endif /* __KERNEL__ */ -#endif /* _ASM_SH_RWSEM_H */ diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild index e928618838bc..6024c26c0585 100644 --- a/arch/sparc/include/asm/Kbuild +++ b/arch/sparc/include/asm/Kbuild @@ -16,6 +16,7 @@ generic-y += mm-arch-hooks.h generic-y += module.h generic-y += mutex.h generic-y += preempt.h +generic-y += rwsem.h generic-y += serial.h generic-y += trace_clock.h generic-y += types.h diff --git a/arch/sparc/include/asm/rwsem.h b/arch/sparc/include/asm/rwsem.h deleted file mode 100644 index 069bf4d663a1..000000000000 --- a/arch/sparc/include/asm/rwsem.h +++ /dev/null @@ -1,124 +0,0 @@ -/* - * rwsem.h: R/W semaphores implemented using CAS - * - * Written by David S. Miller (davem@redhat.com), 2001. - * Derived from asm-i386/rwsem.h - */ -#ifndef _SPARC64_RWSEM_H -#define _SPARC64_RWSEM_H - -#ifndef _LINUX_RWSEM_H -#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" -#endif - -#ifdef __KERNEL__ - -#define RWSEM_UNLOCKED_VALUE 0x00000000L -#define RWSEM_ACTIVE_BIAS 0x00000001L -#define RWSEM_ACTIVE_MASK 0xffffffffL -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - if (unlikely(atomic64_inc_return((atomic64_t *)(&sem->count)) <= 0L)) - rwsem_down_read_failed(sem); -} - -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - long tmp; - - while ((tmp = sem->count) >= 0L) { - if (tmp == cmpxchg(&sem->count, tmp, - tmp + RWSEM_ACTIVE_READ_BIAS)) { - return 1; - } - } - return 0; -} - -/* - * lock for writing - */ -static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) -{ - long tmp; - - tmp = atomic64_add_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic64_t *)(&sem->count)); - if (unlikely(tmp != RWSEM_ACTIVE_WRITE_BIAS)) - rwsem_down_write_failed(sem); -} - -static inline void __down_write(struct rw_semaphore *sem) -{ - __down_write_nested(sem, 0); -} - -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - long tmp; - - tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - return tmp == RWSEM_UNLOCKED_VALUE; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic64_dec_return((atomic64_t *)(&sem->count)); - if (unlikely(tmp < -1L && (tmp & RWSEM_ACTIVE_MASK) == 0L)) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - if (unlikely(atomic64_sub_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic64_t *)(&sem->count)) < 0L)) - rwsem_wake(sem); -} - -/* - * implement atomic add functionality - */ -static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem) -{ - atomic64_add(delta, (atomic64_t *)(&sem->count)); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - long tmp; - - tmp = atomic64_add_return(-RWSEM_WAITING_BIAS, (atomic64_t *)(&sem->count)); - if (tmp < 0L) - rwsem_downgrade_wake(sem); -} - -/* - * implement exchange and add functionality - */ -static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem) -{ - return atomic64_add_return(delta, (atomic64_t *)(&sem->count)); -} - -#endif /* __KERNEL__ */ - -#endif /* _SPARC64_RWSEM_H */ diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index ceec86eb68e9..453744c1d347 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -99,26 +99,36 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) /* * lock for writing */ -static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) +#define ____down_write(sem, slow_path) \ +({ \ + long tmp; \ + struct rw_semaphore* ret; \ + asm volatile("# beginning down_write\n\t" \ + LOCK_PREFIX " xadd %1,(%3)\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 void __down_write(struct rw_semaphore *sem) +static inline int __down_write_killable(struct rw_semaphore *sem) { - __down_write_nested(sem, 0); + 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 be110efa0096..bf2c6074efd2 100644 --- a/arch/x86/lib/rwsem.S +++ b/arch/x86/lib/rwsem.S @@ -29,8 +29,10 @@ * there is contention on the semaphore. * * %eax contains the semaphore pointer on entry. Save the C-clobbered - * registers (%eax, %edx and %ecx) except %eax whish is either a return - * value or just clobbered.. + * registers (%eax, %edx and %ecx) except %eax which is either a return + * value or just gets clobbered. Same is true for %edx so make sure GCC + * reloads it after the slow path, by making it hold a temporary, for + * example see ____down_write(). */ #define save_common_regs \ @@ -106,6 +108,16 @@ ENTRY(call_rwsem_down_write_failed) ret ENDPROC(call_rwsem_down_write_failed) +ENTRY(call_rwsem_down_write_failed_killable) + FRAME_BEGIN + save_common_regs + movq %rax,%rdi + call rwsem_down_write_failed_killable + restore_common_regs + FRAME_END + ret +ENDPROC(call_rwsem_down_write_failed_killable) + ENTRY(call_rwsem_wake) FRAME_BEGIN /* do nothing if still outstanding active readers */ diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild index b56855a1382a..28cf4c5d65ef 100644 --- a/arch/xtensa/include/asm/Kbuild +++ b/arch/xtensa/include/asm/Kbuild @@ -22,6 +22,7 @@ generic-y += mm-arch-hooks.h generic-y += percpu.h generic-y += preempt.h generic-y += resource.h +generic-y += rwsem.h generic-y += sections.h generic-y += siginfo.h generic-y += statfs.h diff --git a/arch/xtensa/include/asm/rwsem.h b/arch/xtensa/include/asm/rwsem.h deleted file mode 100644 index 249619e7e7f2..000000000000 --- a/arch/xtensa/include/asm/rwsem.h +++ /dev/null @@ -1,131 +0,0 @@ -/* - * include/asm-xtensa/rwsem.h - * - * This file is subject to the terms and conditions of the GNU General Public - * License. See the file "COPYING" in the main directory of this archive - * for more details. - * - * Largely copied from include/asm-ppc/rwsem.h - * - * Copyright (C) 2001 - 2005 Tensilica Inc. - */ - -#ifndef _XTENSA_RWSEM_H -#define _XTENSA_RWSEM_H - -#ifndef _LINUX_RWSEM_H -#error "Please don't include <asm/rwsem.h> directly, use <linux/rwsem.h> instead." -#endif - -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - if (atomic_add_return(1,(atomic_t *)(&sem->count)) > 0) - smp_wmb(); - else - rwsem_down_read_failed(sem); -} - -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - int tmp; - - while ((tmp = sem->count) >= 0) { - if (tmp == cmpxchg(&sem->count, tmp, - tmp + RWSEM_ACTIVE_READ_BIAS)) { - smp_wmb(); - return 1; - } - } - return 0; -} - -/* - * lock for writing - */ -static inline void __down_write(struct rw_semaphore *sem) -{ - int tmp; - - tmp = atomic_add_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic_t *)(&sem->count)); - if (tmp == RWSEM_ACTIVE_WRITE_BIAS) - smp_wmb(); - else - rwsem_down_write_failed(sem); -} - -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - int tmp; - - tmp = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - smp_wmb(); - return tmp == RWSEM_UNLOCKED_VALUE; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - int tmp; - - smp_wmb(); - tmp = atomic_sub_return(1,(atomic_t *)(&sem->count)); - if (tmp < -1 && (tmp & RWSEM_ACTIVE_MASK) == 0) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - smp_wmb(); - if (atomic_sub_return(RWSEM_ACTIVE_WRITE_BIAS, - (atomic_t *)(&sem->count)) < 0) - rwsem_wake(sem); -} - -/* - * implement atomic add functionality - */ -static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem) -{ - atomic_add(delta, (atomic_t *)(&sem->count)); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - int tmp; - - smp_wmb(); - tmp = atomic_add_return(-RWSEM_WAITING_BIAS, (atomic_t *)(&sem->count)); - if (tmp < 0) - rwsem_downgrade_wake(sem); -} - -/* - * implement exchange and add functionality - */ -static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem) -{ - smp_mb(); - return atomic_add_return(delta, (atomic_t *)(&sem->count)); -} - -#endif /* _XTENSA_RWSEM_H */ |