Commit 08f36ff6 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Thomas Gleixner
Browse files

lockdep: Make lockdep checking constant 



There are several places in the kernel which would like to pass a const
pointer to lockdep_is_held().  Constify the entire path so nobody has to
trick the compiler.

Signed-off-by: default avatarMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Link: https://lkml.kernel.org/r/20180117151414.23686-3-willy@infradead.org
parent 64f29d1b

include/linux/lockdep.h

+2 −2
Original line number Diff line number Diff line
@@ -337,9 +337,9 @@ extern void lock_release(struct lockdep_map *lock, int nested, 
/*

 * 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_type(const struct lockdep_map *lock, int read);



static inline int lock_is_held(struct lockdep_map *lock)

static inline int lock_is_held(const struct lockdep_map *lock)

{

	return lock_is_held_type(lock, -1);

}

kernel/locking/lockdep.c

+7 −6
Original line number Diff line number Diff line
@@ -648,7 +648,7 @@ static int count_matching_names(struct lock_class *new_class) 
}



static inline struct lock_class *

look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)

look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)

{

	struct lockdep_subclass_key *key;

	struct hlist_head *hash_head;
@@ -3276,7 +3276,7 @@ print_lock_nested_lock_not_held(struct task_struct *curr, 
	return 0;

}



static int __lock_is_held(struct lockdep_map *lock, int read);

static int __lock_is_held(const struct lockdep_map *lock, int read);



/*

 * This gets called for every mutex_lock*()/spin_lock*() operation.
@@ -3485,13 +3485,14 @@ print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock, 
	return 0;

}



static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)

static int match_held_lock(const struct held_lock *hlock,

					const struct lockdep_map *lock)

{

	if (hlock->instance == lock)

		return 1;



	if (hlock->references) {

		struct lock_class *class = lock->class_cache[0];

		const struct lock_class *class = lock->class_cache[0];



		if (!class)

			class = look_up_lock_class(lock, 0);
@@ -3727,7 +3728,7 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) 
	return 1;

}



static int __lock_is_held(struct lockdep_map *lock, int read)

static int __lock_is_held(const struct lockdep_map *lock, int read)

{

	struct task_struct *curr = current;

	int i;
@@ -3941,7 +3942,7 @@ void lock_release(struct lockdep_map *lock, int nested, 
}

EXPORT_SYMBOL_GPL(lock_release);



int lock_is_held_type(struct lockdep_map *lock, int read)

int lock_is_held_type(const struct lockdep_map *lock, int read)

{

	unsigned long flags;

	int ret = 0;

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