From 2e39465abc4b7856a0ea6fcf4f6b4668bb5db877 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 4 Aug 2014 12:07:15 +0200 Subject: locking: Remove deprecated smp_mb__() barriers Its been a while and there are no in-tree users left, so remove the deprecated barriers. Signed-off-by: Peter Zijlstra Cc: Chen, Gong Cc: Jacob Pan Cc: Joe Perches Cc: John Sullivan Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Srinivas Pandruvada Cc: Theodore Ts'o Signed-off-by: Ingo Molnar --- include/linux/atomic.h | 36 ------------------------------------ include/linux/bitops.h | 20 -------------------- 2 files changed, 56 deletions(-) (limited to 'include') diff --git a/include/linux/atomic.h b/include/linux/atomic.h index fef3a809e7cf..5b08a8540ecf 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -3,42 +3,6 @@ #define _LINUX_ATOMIC_H #include -/* - * Provide __deprecated wrappers for the new interface, avoid flag day changes. - * We need the ugly external functions to break header recursion hell. - */ -#ifndef smp_mb__before_atomic_inc -static inline void __deprecated smp_mb__before_atomic_inc(void) -{ - extern void __smp_mb__before_atomic(void); - __smp_mb__before_atomic(); -} -#endif - -#ifndef smp_mb__after_atomic_inc -static inline void __deprecated smp_mb__after_atomic_inc(void) -{ - extern void __smp_mb__after_atomic(void); - __smp_mb__after_atomic(); -} -#endif - -#ifndef smp_mb__before_atomic_dec -static inline void __deprecated smp_mb__before_atomic_dec(void) -{ - extern void __smp_mb__before_atomic(void); - __smp_mb__before_atomic(); -} -#endif - -#ifndef smp_mb__after_atomic_dec -static inline void __deprecated smp_mb__after_atomic_dec(void) -{ - extern void __smp_mb__after_atomic(void); - __smp_mb__after_atomic(); -} -#endif - /** * atomic_add_unless - add unless the number is already a given value * @v: pointer of type atomic_t diff --git a/include/linux/bitops.h b/include/linux/bitops.h index cbc5833fb221..be5fd38bd5a0 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -32,26 +32,6 @@ extern unsigned long __sw_hweight64(__u64 w); */ #include -/* - * Provide __deprecated wrappers for the new interface, avoid flag day changes. - * We need the ugly external functions to break header recursion hell. - */ -#ifndef smp_mb__before_clear_bit -static inline void __deprecated smp_mb__before_clear_bit(void) -{ - extern void __smp_mb__before_atomic(void); - __smp_mb__before_atomic(); -} -#endif - -#ifndef smp_mb__after_clear_bit -static inline void __deprecated smp_mb__after_clear_bit(void) -{ - extern void __smp_mb__after_atomic(void); - __smp_mb__after_atomic(); -} -#endif - #define for_each_set_bit(bit, addr, size) \ for ((bit) = find_first_bit((addr), (size)); \ (bit) < (size); \ -- cgit v1.2.3 From 7608a43d8f2e02f8b532f8e11481d7ecf8b5d3f9 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 30 Jul 2014 13:41:54 -0700 Subject: locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate 4badad35 ("locking/mutex: Disable optimistic spinning on some architectures") added a ARCH_SUPPORTS_ATOMIC_RMW flag to disable the mutex optimistic feature on specific archs. Because CONFIG_MUTEX_SPIN_ON_OWNER only depended on DEBUG and SMP, it was ok to have the ->owner field conditional a bit flexible. However by adding a new variable to the matter, we can waste space with the unused field, ie: CONFIG_SMP && (!CONFIG_MUTEX_SPIN_ON_OWNER && !CONFIG_DEBUG_MUTEX). Signed-off-by: Davidlohr Bueso Acked-by: Jason Low Signed-off-by: Peter Zijlstra Cc: aswin@hp.com Cc: Davidlohr Bueso Cc: Heiko Carstens Cc: Jason Low Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Tim Chen Link: http://lkml.kernel.org/r/1406752916-3341-5-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar --- include/linux/mutex.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mutex.h b/include/linux/mutex.h index 8d5535c58cc2..e4c29418f407 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -52,7 +52,7 @@ struct mutex { atomic_t count; spinlock_t wait_lock; struct list_head wait_list; -#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP) +#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_MUTEX_SPIN_ON_OWNER) struct task_struct *owner; #endif #ifdef CONFIG_MUTEX_SPIN_ON_OWNER -- cgit v1.2.3 From 214e0aed639ef40987bf6159fad303171a6de31e Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Wed, 30 Jul 2014 13:41:55 -0700 Subject: locking/Documentation: Move locking related docs into Documentation/locking/ Specifically: Documentation/locking/lockdep-design.txt Documentation/locking/lockstat.txt Documentation/locking/mutex-design.txt Documentation/locking/rt-mutex-design.txt Documentation/locking/rt-mutex.txt Documentation/locking/spinlocks.txt Documentation/locking/ww-mutex-design.txt Signed-off-by: Davidlohr Bueso Acked-by: Randy Dunlap Signed-off-by: Peter Zijlstra Cc: jason.low2@hp.com Cc: aswin@hp.com Cc: Alexei Starovoitov Cc: Al Viro Cc: Andrew Morton Cc: Chris Mason Cc: Dan Streetman Cc: David Airlie Cc: Davidlohr Bueso Cc: David S. Miller Cc: Greg Kroah-Hartman Cc: Heiko Carstens Cc: Jason Low Cc: Josef Bacik Cc: Kees Cook Cc: Linus Torvalds Cc: Lubomir Rintel Cc: Masanari Iida Cc: Paul E. McKenney Cc: Randy Dunlap Cc: Tim Chen Cc: Vineet Gupta Cc: fengguang.wu@intel.com Link: http://lkml.kernel.org/r/1406752916-3341-6-git-send-email-davidlohr@hp.com Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 2 +- include/linux/mutex.h | 2 +- include/linux/rwsem.h | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 008388f920d7..f388481201cd 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -4,7 +4,7 @@ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra * - * see Documentation/lockdep-design.txt for more details. + * see Documentation/locking/lockdep-design.txt for more details. */ #ifndef __LINUX_LOCKDEP_H #define __LINUX_LOCKDEP_H diff --git a/include/linux/mutex.h b/include/linux/mutex.h index e4c29418f407..cc31498fc526 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -133,7 +133,7 @@ static inline int mutex_is_locked(struct mutex *lock) /* * See kernel/locking/mutex.c for detailed documentation of these APIs. - * Also see Documentation/mutex-design.txt. + * Also see Documentation/locking/mutex-design.txt. */ #ifdef CONFIG_DEBUG_LOCK_ALLOC extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h index 035d3c57fc8a..8f498cdde280 100644 --- a/include/linux/rwsem.h +++ b/include/linux/rwsem.h @@ -149,7 +149,7 @@ extern void downgrade_write(struct rw_semaphore *sem); * static then another method for expressing nested locking is * the explicit definition of lock class keys and the use of * lockdep_set_class() at lock initialization time. - * See Documentation/lockdep-design.txt for more details.) + * See Documentation/locking/lockdep-design.txt for more details.) */ extern void down_read_nested(struct rw_semaphore *sem, int subclass); extern void down_write_nested(struct rw_semaphore *sem, int subclass); -- cgit v1.2.3 From 4999201a59ef555f9105d2bb2459ed895627f7aa Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 8 Aug 2014 12:35:36 +0200 Subject: locking/spinlocks: Always evaluate the second argument of spin_lock_nested() Evaluating a macro argument only if certain configuration options have been selected is confusing and error-prone. Hence always evaluate the second argument of spin_lock_nested(). An intentional side effect of this patch is that it avoids that the following warning is reported for netif_addr_lock_nested() when building with CONFIG_DEBUG_LOCK_ALLOC=n and with W=1: include/linux/netdevice.h: In function 'netif_addr_lock_nested': include/linux/netdevice.h:2865:6: warning: variable 'subclass' set but not used [-Wunused-but-set-variable] int subclass = SINGLE_DEPTH_NESTING; ^ Signed-off-by: Bart Van Assche Signed-off-by: Peter Zijlstra Cc: David Rientjes Cc: David S. Miller Cc: Andrew Morton Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Paul E. McKenney Link: http://lkml.kernel.org/r/53E4A7F8.1040700@acm.org Signed-off-by: Ingo Molnar --- include/linux/spinlock.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 3f2867ff0ced..262ba4ef9a8e 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -197,7 +197,13 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock) _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \ } while (0) #else -# define raw_spin_lock_nested(lock, subclass) _raw_spin_lock(lock) +/* + * Always evaluate the 'subclass' argument to avoid that the compiler + * warns about set-but-not-used variables when building with + * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1. + */ +# define raw_spin_lock_nested(lock, subclass) \ + _raw_spin_lock(((void)(subclass), (lock))) # define raw_spin_lock_nest_lock(lock, nest_lock) _raw_spin_lock(lock) #endif -- cgit v1.2.3 From f0bab73cb539fb803c4d419951e8d28aa4964f8f Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Wed, 6 Aug 2014 13:22:01 -0400 Subject: locking/lockdep: Restrict the use of recursive read_lock() with qrwlock Unlike the original unfair rwlock implementation, queued rwlock will grant lock according to the chronological sequence of the lock requests except when the lock requester is in the interrupt context. Consequently, recursive read_lock calls will now hang the process if there is a write_lock call somewhere in between the read_lock calls. This patch updates the lockdep implementation to look for recursive read_lock calls. A new read state (3) is used to mark those read_lock call that cannot be recursively called except in the interrupt context. The new read state does exhaust the 2 bits available in held_lock:read bit field. The addition of any new read state in the future may require a redesign of how all those bits are squeezed together in the held_lock structure. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra Cc: Maarten Lankhorst Cc: Rik van Riel Cc: Scott J Norton Cc: Fengguang Wu Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1407345722-61615-2-git-send-email-Waiman.Long@hp.com Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index f388481201cd..b5a84b62fb84 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -478,16 +478,24 @@ static inline void print_irqtrace_events(struct task_struct *curr) * on the per lock-class debug mode: */ +/* + * Read states in the 2-bit held_lock:read field: + * 0: Exclusive lock + * 1: Shareable lock, cannot be recursively called + * 2: Shareable lock, can be recursively called + * 3: Shareable lock, cannot be recursively called except in interrupt context + */ #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) +#define lock_acquire_shared_irecursive(l, s, t, n, i) lock_acquire(l, s, t, 3, 1, n, i) #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) #define spin_release(l, n, i) lock_release(l, n, i) #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) -#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) +#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_irecursive(l, s, t, NULL, i) #define rwlock_release(l, n, i) lock_release(l, n, i) #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) -- cgit v1.2.3 From 8acd91e8620836a56ff62028ed28ba629f2881a0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 30 Sep 2014 15:26:00 +0200 Subject: locking/lockdep: Revert qrwlock recusive stuff Commit f0bab73cb539 ("locking/lockdep: Restrict the use of recursive read_lock() with qrwlock") changed lockdep to try and conform to the qrwlock semantics which differ from the traditional rwlock semantics. In particular qrwlock is fair outside of interrupt context, but in interrupt context readers will ignore all fairness. The problem modeling this is that read and write side have different lock state (interrupts) semantics but we only have a single representation of these. Therefore lockdep will get confused, thinking the lock can cause interrupt lock inversions. So revert it for now; the old rwlock semantics were already imperfectly modeled and the qrwlock extra won't fit either. If we want to properly fix this, I think we need to resurrect the work by Gautham did a few years ago that split the read and write state of locks: http://lwn.net/Articles/332801/ FWIW the locking selftest that would've failed (and was reported by Borislav earlier) is something like: RL(X1); /* IRQ-ON */ LOCK(A); UNLOCK(A); RU(X1); IRQ_ENTER(); RL(X1); /* IN-IRQ */ RU(X1); IRQ_EXIT(); At which point it would report that because A is an IRQ-unsafe lock we can suffer the following inversion: CPU0 CPU1 lock(A) lock(X1) lock(A) lock(X1) And this is 'wrong' because X1 can recurse (assuming the above lock are in fact read-lock) but lockdep doesn't know about this. Signed-off-by: Peter Zijlstra (Intel) Cc: Waiman Long Cc: ego@linux.vnet.ibm.com Cc: bp@alien8.de Cc: Linus Torvalds Cc: Paul E. McKenney Link: http://lkml.kernel.org/r/20140930132600.GA7444@worktop.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) (limited to 'include') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index b5a84b62fb84..f388481201cd 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -478,24 +478,16 @@ static inline void print_irqtrace_events(struct task_struct *curr) * on the per lock-class debug mode: */ -/* - * Read states in the 2-bit held_lock:read field: - * 0: Exclusive lock - * 1: Shareable lock, cannot be recursively called - * 2: Shareable lock, can be recursively called - * 3: Shareable lock, cannot be recursively called except in interrupt context - */ #define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i) #define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i) #define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i) -#define lock_acquire_shared_irecursive(l, s, t, n, i) lock_acquire(l, s, t, 3, 1, n, i) #define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) #define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i) #define spin_release(l, n, i) lock_release(l, n, i) #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) -#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_irecursive(l, s, t, NULL, i) +#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) #define rwlock_release(l, n, i) lock_release(l, n, i) #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) -- cgit v1.2.3