75 lines
2.7 KiB
Diff
75 lines
2.7 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 22 Mar 2018 16:22:41 +0100
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Subject: [PATCH 09/10] iommu/amd: Make amd_iommu_devtable_lock a spin_lock
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.16/older/patches-4.16.7-rt1.tar.xz
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Upstream commit 2cd1083d79a0a8c223af430ca97884c28a1e2fc0
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Before commit 0bb6e243d7fb ("iommu/amd: Support IOMMU_DOMAIN_DMA type
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allocation") amd_iommu_devtable_lock had a read_lock() user but now
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there are none. In fact, after the mentioned commit we had only
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write_lock() user of the lock. Since there is no reason to keep it as
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writer lock, change its type to a spin_lock.
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I *think* that we might even be able to remove the lock because all its
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current user seem to have their own protection.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Signed-off-by: Joerg Roedel <jroedel@suse.de>
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---
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drivers/iommu/amd_iommu.c | 14 +++++++-------
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1 file changed, 7 insertions(+), 7 deletions(-)
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--- a/drivers/iommu/amd_iommu.c
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+++ b/drivers/iommu/amd_iommu.c
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@@ -80,7 +80,7 @@
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*/
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#define AMD_IOMMU_PGSIZES ((~0xFFFUL) & ~(2ULL << 38))
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-static DEFINE_RWLOCK(amd_iommu_devtable_lock);
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+static DEFINE_SPINLOCK(amd_iommu_devtable_lock);
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static DEFINE_SPINLOCK(pd_bitmap_lock);
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static DEFINE_SPINLOCK(iommu_table_lock);
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@@ -2096,9 +2096,9 @@ static int attach_device(struct device *
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}
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skip_ats_check:
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- write_lock_irqsave(&amd_iommu_devtable_lock, flags);
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+ spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
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ret = __attach_device(dev_data, domain);
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- write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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+ spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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/*
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* We might boot into a crash-kernel here. The crashed kernel
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@@ -2148,9 +2148,9 @@ static void detach_device(struct device
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domain = dev_data->domain;
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/* lock device table */
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- write_lock_irqsave(&amd_iommu_devtable_lock, flags);
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+ spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
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__detach_device(dev_data);
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- write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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+ spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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if (!dev_is_pci(dev))
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return;
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@@ -2813,7 +2813,7 @@ static void cleanup_domain(struct protec
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struct iommu_dev_data *entry;
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unsigned long flags;
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- write_lock_irqsave(&amd_iommu_devtable_lock, flags);
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+ spin_lock_irqsave(&amd_iommu_devtable_lock, flags);
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while (!list_empty(&domain->dev_list)) {
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entry = list_first_entry(&domain->dev_list,
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@@ -2821,7 +2821,7 @@ static void cleanup_domain(struct protec
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__detach_device(entry);
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}
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- write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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+ spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
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}
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static void protection_domain_free(struct protection_domain *domain)
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