From f8319483f57f1ca22370f4150bb990aca7728a67 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 30 Nov 2016 14:32:25 +1100 Subject: [PATCH] locking/lockdep: Provide a type check for lock_is_held Christoph requested lockdep_assert_held() variants that distinguish between held-for-read or held-for-write. Provide: int lock_is_held_type(struct lockdep_map *lock, int read) which takes the same argument as lock_acquire(.read) and matches it to the held_lock instance. Use of this function should be gated by the debug_locks variable. When that is 0 the return value of the lock_is_held_type() function is undefined. This is done to allow both negative and positive tests for holding locks. By default we provide (positive) lockdep_assert_held{,_exclusive,_read}() macros. Requested-by: Christoph Hellwig Signed-off-by: Peter Zijlstra (Intel) Tested-by: Jens Axboe Reviewed-by: Darrick J. Wong Signed-off-by: Dave Chinner --- include/linux/lockdep.h | 25 +++++++++++++++++++++++-- kernel/locking/lockdep.c | 20 ++++++++++++-------- 2 files changed, 35 insertions(+), 10 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index c1458fede1f9..1e327bb80838 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -338,9 +338,18 @@ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, extern void lock_release(struct lockdep_map *lock, int nested, unsigned long ip); -#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) +/* + * Same "read" as for lock_acquire(), except -1 means any. + */ +extern int lock_is_held_type(struct lockdep_map *lock, int read); -extern int lock_is_held(struct lockdep_map *lock); +static inline int lock_is_held(struct lockdep_map *lock) +{ + return lock_is_held_type(lock, -1); +} + +#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map) +#define lockdep_is_held_type(lock, r) lock_is_held_type(&(lock)->dep_map, (r)) extern void lock_set_class(struct lockdep_map *lock, const char *name, struct lock_class_key *key, unsigned int subclass, @@ -372,6 +381,14 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie); WARN_ON(debug_locks && !lockdep_is_held(l)); \ } while (0) +#define lockdep_assert_held_exclusive(l) do { \ + WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \ + } while (0) + +#define lockdep_assert_held_read(l) do { \ + WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \ + } while (0) + #define lockdep_assert_held_once(l) do { \ WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ } while (0) @@ -428,7 +445,11 @@ struct lock_class_key { }; #define lockdep_depth(tsk) (0) +#define lockdep_is_held_type(l, r) (1) + #define lockdep_assert_held(l) do { (void)(l); } while (0) +#define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0) +#define lockdep_assert_held_read(l) do { (void)(l); } while (0) #define lockdep_assert_held_once(l) do { (void)(l); } while (0) #define lockdep_recursing(tsk) (0) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 589d763a49b3..cff580a6edf9 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3188,7 +3188,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr, return 0; } -static int __lock_is_held(struct lockdep_map *lock); +static int __lock_is_held(struct lockdep_map *lock, int read); /* * This gets called for every mutex_lock*()/spin_lock*() operation. @@ -3329,7 +3329,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, } chain_key = iterate_chain_key(chain_key, class_idx); - if (nest_lock && !__lock_is_held(nest_lock)) + if (nest_lock && !__lock_is_held(nest_lock, -1)) return print_lock_nested_lock_not_held(curr, hlock, ip); if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) @@ -3576,7 +3576,7 @@ found_it: return 1; } -static int __lock_is_held(struct lockdep_map *lock) +static int __lock_is_held(struct lockdep_map *lock, int read) { struct task_struct *curr = current; int i; @@ -3584,8 +3584,12 @@ static int __lock_is_held(struct lockdep_map *lock) for (i = 0; i < curr->lockdep_depth; i++) { struct held_lock *hlock = curr->held_locks + i; - if (match_held_lock(hlock, lock)) - return 1; + if (match_held_lock(hlock, lock)) { + if (read == -1 || hlock->read == read) + return 1; + + return 0; + } } return 0; @@ -3769,7 +3773,7 @@ void lock_release(struct lockdep_map *lock, int nested, } EXPORT_SYMBOL_GPL(lock_release); -int lock_is_held(struct lockdep_map *lock) +int lock_is_held_type(struct lockdep_map *lock, int read) { unsigned long flags; int ret = 0; @@ -3781,13 +3785,13 @@ int lock_is_held(struct lockdep_map *lock) check_flags(flags); current->lockdep_recursion = 1; - ret = __lock_is_held(lock); + ret = __lock_is_held(lock, read); current->lockdep_recursion = 0; raw_local_irq_restore(flags); return ret; } -EXPORT_SYMBOL_GPL(lock_is_held); +EXPORT_SYMBOL_GPL(lock_is_held_type); struct pin_cookie lock_pin_lock(struct lockdep_map *lock) {