Commit-ID: f6ec8829ac9d59b637366c13038f15d6f6156fe1 Gitweb: https://git.kernel.org/tip/f6ec8829ac9d59b637366c13038f15d6f6156fe1 Author: Yuyang Du <[email protected]> AuthorDate: Mon, 6 May 2019 16:19:24 +0800 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 3 Jun 2019 11:55:43 +0200
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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/lockdep.h | 1 + init/init_task.c | 2 +- kernel/locking/lockdep.c | 18 +++++++++--------- 3 files changed, 11 insertions(+), 10 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 5d05b8149f19..d4e69595dbd4 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -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 { /* diff --git a/init/init_task.c b/init/init_task.c index 1b15cb90d64f..afa6ad795355 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -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 diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index b7d9c28ecf3b..9edf6f12b711 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -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)
