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powerpc: qspinlock: Mark accesses to qnode lock checks

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The powerpc implementation of qspinlocks will both poll and spin on the
bitlock guarding a qnode. Mark these accesses with READ_ONCE to convey
to KCSAN that polling is intentional here.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230510033117.1395895-2-rmclure@linux.ibm.com
This commit is contained in:
Rohan McLure 2023-05-10 13:31:07 +10:00 • committed by Michael Ellerman
parent 98e61df570
commit 03d44ee80e
1 changed files with 2 additions and 2 deletions
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4
arch/powerpc/lib/qspinlock.c
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@ -435,7 +435,7 @@ yield_prev:
smp_rmb(); /* See __yield_to_locked_owner comment */
if (!node->locked) {
if (!READ_ONCE(node->locked)) {
yield_to_preempted(prev_cpu, yield_count);
spin_begin();
return preempted;
@ -584,7 +584,7 @@ static __always_inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, b
/* Wait for mcs node lock to be released */
spin_begin();
while (!node->locked) {
while (!READ_ONCE(node->locked)) {
spec_barrier();
if (yield_to_prev(lock, node, old, paravirt))