Commit f6ec8829 authored by Yuyang Du's avatar Yuyang Du Committed by Ingo Molnar

locking/lockdep: Define INITIAL_CHAIN_KEY for chain keys to start with

Chain keys are computed using Jenkins hash function, which needs an initial
hash to start with. Dedicate a macro to make this clear and configurable. A
later patch changes this initial chain key.
Signed-off-by: default avatarYuyang Du <duyuyang@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bvanassche@acm.org
Cc: frederic@kernel.org
Cc: ming.lei@redhat.com
Cc: will.deacon@arm.com
Link: https://lkml.kernel.org/r/20190506081939.74287-9-duyuyang@gmail.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e196e479
...@@ -229,6 +229,7 @@ struct lock_chain { ...@@ -229,6 +229,7 @@ struct lock_chain {
* bitfield and hitting the BUG in hlock_class(). * bitfield and hitting the BUG in hlock_class().
*/ */
#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1) #define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
#define INITIAL_CHAIN_KEY 0
struct held_lock { struct held_lock {
/* /*
......
...@@ -167,7 +167,7 @@ struct task_struct init_task ...@@ -167,7 +167,7 @@ struct task_struct init_task
#endif #endif
#ifdef CONFIG_LOCKDEP #ifdef CONFIG_LOCKDEP
.lockdep_depth = 0, /* no locks held yet */ .lockdep_depth = 0, /* no locks held yet */
.curr_chain_key = 0, .curr_chain_key = INITIAL_CHAIN_KEY,
.lockdep_recursion = 0, .lockdep_recursion = 0,
#endif #endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER #ifdef CONFIG_FUNCTION_GRAPH_TRACER
......
...@@ -362,7 +362,7 @@ static inline u64 iterate_chain_key(u64 key, u32 idx) ...@@ -362,7 +362,7 @@ static inline u64 iterate_chain_key(u64 key, u32 idx)
void lockdep_init_task(struct task_struct *task) void lockdep_init_task(struct task_struct *task)
{ {
task->lockdep_depth = 0; /* no locks held yet */ task->lockdep_depth = 0; /* no locks held yet */
task->curr_chain_key = 0; task->curr_chain_key = INITIAL_CHAIN_KEY;
task->lockdep_recursion = 0; task->lockdep_recursion = 0;
} }
...@@ -857,7 +857,7 @@ static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; ...@@ -857,7 +857,7 @@ static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
static bool check_lock_chain_key(struct lock_chain *chain) static bool check_lock_chain_key(struct lock_chain *chain)
{ {
#ifdef CONFIG_PROVE_LOCKING #ifdef CONFIG_PROVE_LOCKING
u64 chain_key = 0; u64 chain_key = INITIAL_CHAIN_KEY;
int i; int i;
for (i = chain->base; i < chain->base + chain->depth; i++) for (i = chain->base; i < chain->base + chain->depth; i++)
...@@ -2524,7 +2524,7 @@ static void ...@@ -2524,7 +2524,7 @@ static void
print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next) print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
{ {
struct held_lock *hlock; struct held_lock *hlock;
u64 chain_key = 0; u64 chain_key = INITIAL_CHAIN_KEY;
int depth = curr->lockdep_depth; int depth = curr->lockdep_depth;
int i = get_first_held_lock(curr, hlock_next); int i = get_first_held_lock(curr, hlock_next);
...@@ -2544,7 +2544,7 @@ print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_ne ...@@ -2544,7 +2544,7 @@ print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_ne
static void print_chain_keys_chain(struct lock_chain *chain) static void print_chain_keys_chain(struct lock_chain *chain)
{ {
int i; int i;
u64 chain_key = 0; u64 chain_key = INITIAL_CHAIN_KEY;
int class_id; int class_id;
printk("depth: %u\n", chain->depth); printk("depth: %u\n", chain->depth);
...@@ -2848,7 +2848,7 @@ static void check_chain_key(struct task_struct *curr) ...@@ -2848,7 +2848,7 @@ static void check_chain_key(struct task_struct *curr)
#ifdef CONFIG_DEBUG_LOCKDEP #ifdef CONFIG_DEBUG_LOCKDEP
struct held_lock *hlock, *prev_hlock = NULL; struct held_lock *hlock, *prev_hlock = NULL;
unsigned int i; unsigned int i;
u64 chain_key = 0; u64 chain_key = INITIAL_CHAIN_KEY;
for (i = 0; i < curr->lockdep_depth; i++) { for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i; hlock = curr->held_locks + i;
...@@ -2872,7 +2872,7 @@ static void check_chain_key(struct task_struct *curr) ...@@ -2872,7 +2872,7 @@ static void check_chain_key(struct task_struct *curr)
if (prev_hlock && (prev_hlock->irq_context != if (prev_hlock && (prev_hlock->irq_context !=
hlock->irq_context)) hlock->irq_context))
chain_key = 0; chain_key = INITIAL_CHAIN_KEY;
chain_key = iterate_chain_key(chain_key, hlock->class_idx); chain_key = iterate_chain_key(chain_key, hlock->class_idx);
prev_hlock = hlock; prev_hlock = hlock;
} }
...@@ -3787,14 +3787,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, ...@@ -3787,14 +3787,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
/* /*
* How can we have a chain hash when we ain't got no keys?! * How can we have a chain hash when we ain't got no keys?!
*/ */
if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
return 0; return 0;
chain_head = 1; chain_head = 1;
} }
hlock->prev_chain_key = chain_key; hlock->prev_chain_key = chain_key;
if (separate_irq_context(curr, hlock)) { if (separate_irq_context(curr, hlock)) {
chain_key = 0; chain_key = INITIAL_CHAIN_KEY;
chain_head = 1; chain_head = 1;
} }
chain_key = iterate_chain_key(chain_key, class_idx); chain_key = iterate_chain_key(chain_key, class_idx);
...@@ -4636,7 +4636,7 @@ static void remove_class_from_lock_chain(struct pending_free *pf, ...@@ -4636,7 +4636,7 @@ static void remove_class_from_lock_chain(struct pending_free *pf,
return; return;
recalc: recalc:
chain_key = 0; chain_key = INITIAL_CHAIN_KEY;
for (i = chain->base; i < chain->base + chain->depth; i++) for (i = chain->base; i < chain->base + chain->depth; i++)
chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1); chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1);
if (chain->depth && chain->chain_key == chain_key) if (chain->depth && chain->chain_key == chain_key)
......
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