50 lines
1.7 KiB
Diff
50 lines
1.7 KiB
Diff
From c07f325700496f69d09b17356014b35c3aa5c12e Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Tue, 5 Sep 2017 14:11:41 +0200
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Subject: [PATCH 339/365] iommu/amd: Use raw_cpu_ptr() instead of get_cpu_ptr()
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for ->flush_queue
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get_cpu_ptr() disabled preemption and returns the ->flush_queue object
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of the current CPU. raw_cpu_ptr() does the same except that it not
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disable preemption which means the scheduler can move it to another CPU
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after it 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: stable-rt@vger.kernel.org
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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: Vinod Adhikary <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/amd_iommu.c | 4 +---
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1 file changed, 1 insertion(+), 3 deletions(-)
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diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
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index e5693cbc0e3b..573e9279289e 100644
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--- a/drivers/iommu/amd_iommu.c
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+++ b/drivers/iommu/amd_iommu.c
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@@ -2315,7 +2315,7 @@ static void queue_add(struct dma_ops_domain *dma_dom,
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pages = __roundup_pow_of_two(pages);
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address >>= PAGE_SHIFT;
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- queue = get_cpu_ptr(&flush_queue);
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+ queue = raw_cpu_ptr(&flush_queue);
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spin_lock_irqsave(&queue->lock, flags);
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if (queue->next == FLUSH_QUEUE_SIZE)
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@@ -2332,8 +2332,6 @@ static void queue_add(struct dma_ops_domain *dma_dom,
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if (atomic_cmpxchg(&queue_timer_on, 0, 1) == 0)
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mod_timer(&queue_timer, jiffies + msecs_to_jiffies(10));
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-
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- put_cpu_ptr(&flush_queue);
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}
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--
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2.28.0
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