From bba2a8f1f974a45ca6ceaf688b2be7bc1c418a2f Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 28 Dec 2018 06:02:01 +0100 Subject: [PATCH] locking/lockdep: Provide enum lock_usage_bit mask names It makes the code more self-explanatory and tells throughout the code what magic number refers to: - state (Hardirq/Softirq) - direction (used in or enabled above state) - read or write We can even remove some comments that were compensating for the lack of those constant names. Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: https://lkml.kernel.org/r/1545973321-24422-3-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar --- kernel/locking/lockdep.c | 33 ++++++++++-------------------- kernel/locking/lockdep_internals.h | 4 ++++ 2 files changed, 15 insertions(+), 22 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 1dcd8341e35b..608f74ed8bb9 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1624,29 +1624,18 @@ static const char *state_rnames[] = { static inline const char *state_name(enum lock_usage_bit bit) { - return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; + return (bit & LOCK_USAGE_READ_MASK) ? state_rnames[bit >> 2] : state_names[bit >> 2]; } static int exclusive_bit(int new_bit) { - /* - * USED_IN - * USED_IN_READ - * ENABLED - * ENABLED_READ - * - * bit 0 - write/read - * bit 1 - used_in/enabled - * bit 2+ state - */ - - int state = new_bit & ~3; - int dir = new_bit & 2; + int state = new_bit & LOCK_USAGE_STATE_MASK; + int dir = new_bit & LOCK_USAGE_DIR_MASK; /* * keep state, bit flip the direction and strip read. */ - return state | (dir ^ 2); + return state | (dir ^ LOCK_USAGE_DIR_MASK); } static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, @@ -2662,8 +2651,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit new_bit) { int excl_bit = exclusive_bit(new_bit); - int read = new_bit & 1; - int dir = new_bit & 2; + int read = new_bit & LOCK_USAGE_READ_MASK; + int dir = new_bit & LOCK_USAGE_DIR_MASK; /* * mark USED_IN has to look forwards -- to ensure no dependency @@ -2687,19 +2676,19 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this, * states. */ if ((!read || !dir || STRICT_READ_CHECKS) && - !usage(curr, this, excl_bit, state_name(new_bit & ~1))) + !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK))) return 0; /* * Check for read in write conflicts */ if (!read) { - if (!valid_state(curr, this, new_bit, excl_bit + 1)) + if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK)) return 0; if (STRICT_READ_CHECKS && - !usage(curr, this, excl_bit + 1, - state_name(new_bit + 1))) + !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK, + state_name(new_bit + LOCK_USAGE_READ_MASK))) return 0; } @@ -2723,7 +2712,7 @@ mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit) hlock = curr->held_locks + i; if (hlock->read) - hlock_bit += 1; /* READ */ + hlock_bit += LOCK_USAGE_READ_MASK; BUG_ON(hlock_bit >= LOCK_USAGE_STATES); diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 88c847a41c8a..2ebb9d0ea91c 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -22,6 +22,10 @@ enum lock_usage_bit { LOCK_USAGE_STATES }; +#define LOCK_USAGE_READ_MASK 1 +#define LOCK_USAGE_DIR_MASK 2 +#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK)) + /* * Usage-state bitmasks: */