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43 lines
1.4 KiB
Diff
43 lines
1.4 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 21 Sep 2017 17:21:40 +0200
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Subject: [PATCH] iommu/iova: Use raw_cpu_ptr() instead of get_cpu_ptr() for
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->fq
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get_cpu_ptr() disabled preemption and returns the ->fq object of the
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current CPU. raw_cpu_ptr() does the same except that it not disable
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preemption which means the scheduler can move it to another CPU after it
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obtained the per-CPU object.
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In this case this is not bad because the data structure itself is
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protected with a spin_lock. This change shouldn't matter however on RT
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it does because the sleeping lock can't be accessed with disabled
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preemption.
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Cc: Joerg Roedel <joro@8bytes.org>
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Cc: iommu@lists.linux-foundation.org
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Reported-by: vinadhy@gmail.com
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/iommu/iova.c | 4 +---
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1 file changed, 1 insertion(+), 3 deletions(-)
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--- a/drivers/iommu/iova.c
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+++ b/drivers/iommu/iova.c
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@@ -570,7 +570,7 @@ void queue_iova(struct iova_domain *iova
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unsigned long pfn, unsigned long pages,
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unsigned long data)
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{
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- struct iova_fq *fq = get_cpu_ptr(iovad->fq);
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+ struct iova_fq *fq = raw_cpu_ptr(iovad->fq);
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unsigned long flags;
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unsigned idx;
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@@ -600,8 +600,6 @@ void queue_iova(struct iova_domain *iova
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if (atomic_cmpxchg(&iovad->fq_timer_on, 0, 1) == 0)
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mod_timer(&iovad->fq_timer,
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jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
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-
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- put_cpu_ptr(iovad->fq);
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}
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EXPORT_SYMBOL_GPL(queue_iova);
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