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locking/lockdep: Provide a type check for lock_is_held

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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 <hch@lst.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Peter Zijlstra 2016-11-30 14:32:25 +11:00 committed by Dave Chinner
parent 3816199506
commit f8319483f5
2 changed files with 35 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

25
include/linux/lockdep.h
View file

@ -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, extern void lock_release(struct lockdep_map *lock, int nested,
unsigned long ip); 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, extern void lock_set_class(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, unsigned int subclass, 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)); \ WARN_ON(debug_locks && !lockdep_is_held(l)); \
} while (0) } 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 { \ #define lockdep_assert_held_once(l) do { \
WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \ WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
} while (0) } while (0)
@ -428,7 +445,11 @@ struct lock_class_key { };
#define lockdep_depth(tsk) (0) #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(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_assert_held_once(l) do { (void)(l); } while (0)
#define lockdep_recursing(tsk) (0) #define lockdep_recursing(tsk) (0)

20
kernel/locking/lockdep.c
View file

@ -3188,7 +3188,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr,
return 0; 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. * 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); 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); return print_lock_nested_lock_not_held(curr, hlock, ip);
if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
@ -3576,7 +3576,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
return 1; 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; struct task_struct *curr = current;
int i; int i;
@ -3584,8 +3584,12 @@ static int __lock_is_held(struct lockdep_map *lock)
for (i = 0; i < curr->lockdep_depth; i++) { for (i = 0; i < curr->lockdep_depth; i++) {
struct held_lock *hlock = curr->held_locks + i; struct held_lock *hlock = curr->held_locks + i;
if (match_held_lock(hlock, lock)) if (match_held_lock(hlock, lock)) {
return 1; if (read == -1 || hlock->read == read)
return 1;
return 0;
}
} }
return 0; return 0;
@ -3769,7 +3773,7 @@ void lock_release(struct lockdep_map *lock, int nested,
} }
EXPORT_SYMBOL_GPL(lock_release); 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; unsigned long flags;
int ret = 0; int ret = 0;
@ -3781,13 +3785,13 @@ int lock_is_held(struct lockdep_map *lock)
check_flags(flags); check_flags(flags);
current->lockdep_recursion = 1; current->lockdep_recursion = 1;
ret = __lock_is_held(lock); ret = __lock_is_held(lock, read);
current->lockdep_recursion = 0; current->lockdep_recursion = 0;
raw_local_irq_restore(flags); raw_local_irq_restore(flags);
return ret; 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) struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
{ {