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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: Yuyang Du <duyuyang@gmail.com>
Signed-off-by: Peter 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.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
alistair/sunxi64-5.4-dsi
Yuyang Du 2019-05-06 16:19:24 +08:00 committed by Ingo Molnar
parent e196e479a3
commit f6ec8829ac
3 changed files with 11 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/lockdep.h
View File

@ -229,6 +229,7 @@ struct lock_chain {
* bitfield and hitting the BUG in hlock_class().
*/
#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
#define INITIAL_CHAIN_KEY 0
struct held_lock {
/*

2
init/init_task.c
View File

@ -167,7 +167,7 @@ struct task_struct init_task
#endif
#ifdef CONFIG_LOCKDEP
.lockdep_depth = 0, /* no locks held yet */
.curr_chain_key = 0,
.curr_chain_key = INITIAL_CHAIN_KEY,
.lockdep_recursion = 0,
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER

18
kernel/locking/lockdep.c
View File

@ -362,7 +362,7 @@ static inline u64 iterate_chain_key(u64 key, u32 idx)
void lockdep_init_task(struct task_struct *task)
{
task->lockdep_depth = 0; /* no locks held yet */
task->curr_chain_key = 0;
task->curr_chain_key = INITIAL_CHAIN_KEY;
task->lockdep_recursion = 0;
}
@ -857,7 +857,7 @@ static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
static bool check_lock_chain_key(struct lock_chain *chain)
{
#ifdef CONFIG_PROVE_LOCKING
u64 chain_key = 0;
u64 chain_key = INITIAL_CHAIN_KEY;
int i;
for (i = chain->base; i < chain->base + chain->depth; i++)
@ -2524,7 +2524,7 @@ static void
print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
{
struct held_lock *hlock;
u64 chain_key = 0;
u64 chain_key = INITIAL_CHAIN_KEY;
int depth = curr->lockdep_depth;
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
static void print_chain_keys_chain(struct lock_chain *chain)
{
int i;
u64 chain_key = 0;
u64 chain_key = INITIAL_CHAIN_KEY;
int class_id;
printk("depth: %u\n", chain->depth);
@ -2848,7 +2848,7 @@ static void check_chain_key(struct task_struct *curr)
#ifdef CONFIG_DEBUG_LOCKDEP
struct held_lock *hlock, *prev_hlock = NULL;
unsigned int i;
u64 chain_key = 0;
u64 chain_key = INITIAL_CHAIN_KEY;
for (i = 0; i < curr->lockdep_depth; i++) {
hlock = curr->held_locks + i;
@ -2872,7 +2872,7 @@ static void check_chain_key(struct task_struct *curr)
if (prev_hlock && (prev_hlock->irq_context !=
hlock->irq_context))
chain_key = 0;
chain_key = INITIAL_CHAIN_KEY;
chain_key = iterate_chain_key(chain_key, hlock->class_idx);
prev_hlock = hlock;
}
@ -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?!
*/
if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
if (DEBUG_LOCKS_WARN_ON(chain_key != INITIAL_CHAIN_KEY))
return 0;
chain_head = 1;
}
hlock->prev_chain_key = chain_key;
if (separate_irq_context(curr, hlock)) {
chain_key = 0;
chain_key = INITIAL_CHAIN_KEY;
chain_head = 1;
}
chain_key = iterate_chain_key(chain_key, class_idx);
@ -4636,7 +4636,7 @@ static void remove_class_from_lock_chain(struct pending_free *pf,
return;
recalc:
chain_key = 0;
chain_key = INITIAL_CHAIN_KEY;
for (i = chain->base; i < chain->base + chain->depth; i++)
chain_key = iterate_chain_key(chain_key, chain_hlocks[i] + 1);
if (chain->depth && chain->chain_key == chain_key)