Messages in this thread Patch in this message | | | From | Yuyang Du <> | Subject | [PATCH v3 03/18] locking/lockdep: Adjust lock usage bit character checks | Date | Thu, 21 Mar 2019 15:57:10 +0800 |
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The lock usage bit characters are defined and determined with tricks. Use a macro and add some explanation to make it a bit clearer. Then adjust the logic to check the usage, which optimizes the code a bit.
No functional change.
Signed-off-by: Yuyang Du <duyuyang@gmail.com> --- kernel/locking/lockdep.c | 21 ++++++++++++++++----- kernel/locking/lockdep_internals.h | 1 + 2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 41137ad..db0473d 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -514,15 +514,26 @@ static inline unsigned long lock_flag(enum lock_usage_bit bit) static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) { + /* + * The usage character defaults to '.' (i.e., irqs disabled and not in + * irq context), which is the safest usage category. + */ char c = '.'; - if (class->usage_mask & lock_flag(bit + 2)) + /* + * The order of the following usage checks matters, which will + * result in the outcome character as follows: + * + * - '+': irq is enabled and not in irq context + * - '-': in irq context and irq is disabled + * - '?': in irq context and irq is enabled + */ + if (class->usage_mask & lock_flag(bit + LOCK_USAGE_TO_ENABLED_STEP)) { c = '+'; - if (class->usage_mask & lock_flag(bit)) { - c = '-'; - if (class->usage_mask & lock_flag(bit + 2)) + if (class->usage_mask & lock_flag(bit)) c = '?'; - } + } else if (class->usage_mask & lock_flag(bit)) + c = '-'; return c; } diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index d4c1974..2fd31d5 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -25,6 +25,7 @@ enum lock_usage_bit { #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)) +#define LOCK_USAGE_TO_ENABLED_STEP 2 /* * Usage-state bitmasks: -- 1.8.3.1
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