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Commit 94e2cc4d authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Alex Williamson
Browse files

iommu/iova: Use raw_cpu_ptr() instead of get_cpu_ptr() for ->fq 



get_cpu_ptr() disabled preemption and returns the ->fq object of the
current CPU. raw_cpu_ptr() does the same except that it not disable
preemption which means the scheduler can move it to another CPU after it
obtained the per-CPU object.
In this case this is not bad because the data structure itself is
protected with a spin_lock. This change shouldn't matter however on RT
it does because the sleeping lock can't be accessed with disabled
preemption.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Reported-by: default avatar <vinadhy@gmail.com>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent a5934725

drivers/iommu/iova.c

+1 −3
Original line number Diff line number Diff line
@@ -542,7 +542,7 @@ void queue_iova(struct iova_domain *iovad, 
		unsigned long pfn, unsigned long pages,

		unsigned long data)

{

	struct iova_fq *fq = get_cpu_ptr(iovad->fq);

	struct iova_fq *fq = raw_cpu_ptr(iovad->fq);

	unsigned long flags;

	unsigned idx;
@@ -572,8 +572,6 @@ void queue_iova(struct iova_domain *iovad, 
	if (atomic_cmpxchg(&iovad->fq_timer_on, 0, 1) == 0)

		mod_timer(&iovad->fq_timer,

			  jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));



	put_cpu_ptr(iovad->fq);

}

EXPORT_SYMBOL_GPL(queue_iova);