s390/spinlock: refactor arch_spin_lock_wait[_flags]
Reorder the spinlock wait code to make it more readable. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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@ -31,23 +31,31 @@ void arch_spin_lock_wait(arch_spinlock_t *lp)
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int count;
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while (1) {
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owner = lp->lock;
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if (!owner || smp_vcpu_scheduled(~owner)) {
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count = spin_retry;
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do {
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if (arch_spin_is_locked(lp))
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continue;
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owner = ACCESS_ONCE(lp->lock);
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/* Try to get the lock if it is free. */
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if (!owner) {
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if (_raw_compare_and_swap(&lp->lock, 0, cpu))
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return;
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} while (count-- > 0);
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if (MACHINE_IS_LPAR)
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continue;
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}
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owner = lp->lock;
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if (owner)
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/* Check if the lock owner is running. */
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if (!smp_vcpu_scheduled(~owner)) {
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smp_yield_cpu(~owner);
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continue;
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}
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/* Loop for a while on the lock value. */
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count = spin_retry;
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do {
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owner = ACCESS_ONCE(lp->lock);
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} while (owner && count-- > 0);
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if (!owner)
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continue;
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/*
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* For multiple layers of hypervisors, e.g. z/VM + LPAR
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* yield the CPU if the lock is still unavailable.
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*/
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if (!MACHINE_IS_LPAR)
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smp_yield_cpu(~owner);
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if (_raw_compare_and_swap(&lp->lock, 0, cpu))
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return;
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}
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}
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EXPORT_SYMBOL(arch_spin_lock_wait);
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@ -60,27 +68,32 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags)
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local_irq_restore(flags);
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while (1) {
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owner = lp->lock;
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if (!owner || smp_vcpu_scheduled(~owner)) {
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count = spin_retry;
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do {
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if (arch_spin_is_locked(lp))
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continue;
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owner = ACCESS_ONCE(lp->lock);
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/* Try to get the lock if it is free. */
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if (!owner) {
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local_irq_disable();
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if (_raw_compare_and_swap(&lp->lock, 0, cpu))
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return;
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local_irq_restore(flags);
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} while (count-- > 0);
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if (MACHINE_IS_LPAR)
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}
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/* Check if the lock owner is running. */
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if (!smp_vcpu_scheduled(~owner)) {
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smp_yield_cpu(~owner);
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continue;
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}
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owner = lp->lock;
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if (owner)
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/* Loop for a while on the lock value. */
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count = spin_retry;
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do {
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owner = ACCESS_ONCE(lp->lock);
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} while (owner && count-- > 0);
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if (!owner)
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continue;
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/*
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* For multiple layers of hypervisors, e.g. z/VM + LPAR
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* yield the CPU if the lock is still unavailable.
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*/
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if (!MACHINE_IS_LPAR)
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smp_yield_cpu(~owner);
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local_irq_disable();
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if (_raw_compare_and_swap(&lp->lock, 0, cpu))
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return;
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local_irq_restore(flags);
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}
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}
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EXPORT_SYMBOL(arch_spin_lock_wait_flags);
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