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locking/qspinlock: Always evaluate lockevent* non-event parameter once

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The 'inc' parameter of lockevent_add() and the cond parameter of
lockevent_cond_inc() are only evaluated when CONFIG_LOCK_EVENT_COUNTS
is on. That can cause problem if those parameters are expressions
with side effect like a "++". Fix this by evaluating those non-event
parameters once even if CONFIG_LOCK_EVENT_COUNTS is off. This will also
eliminate the need of the __maybe_unused attribute to the wait_early
local variable in pv_wait_node().

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240319005004.1692705-1-longman@redhat.com
This commit is contained in:
Waiman Long 2024-03-18 20:50:04 -04:00 committed by Ingo Molnar
parent 4ae3dc83b0
commit 3774b28d8f
2 changed files with 3 additions and 3 deletions
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4
kernel/locking/lock_events.h
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@ -53,8 +53,8 @@ static inline void __lockevent_add(enum lock_events event, int inc)
#else /* CONFIG_LOCK_EVENT_COUNTS */
#define lockevent_inc(ev)
#define lockevent_add(ev, c)
#define lockevent_cond_inc(ev, c)
#define lockevent_add(ev, c) do { (void)(c); } while (0)
#define lockevent_cond_inc(ev, c) do { (void)(c); } while (0)
#endif /* CONFIG_LOCK_EVENT_COUNTS */

2
kernel/locking/qspinlock_paravirt.h
View file

@ -294,7 +294,7 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
{
struct pv_node *pn = (struct pv_node *)node;
struct pv_node *pp = (struct pv_node *)prev;
bool __maybe_unused wait_early;
bool wait_early;
int loop;
for (;;) {