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Commit 2cd1083d authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Joerg Roedel
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iommu/amd: Make amd_iommu_devtable_lock a spin_lock 



Before commit 0bb6e243 ("iommu/amd: Support IOMMU_DOMAIN_DMA type
allocation") amd_iommu_devtable_lock had a read_lock() user but now
there are none. In fact, after the mentioned commit we had only
write_lock() user of the lock. Since there is no reason to keep it as
writer lock, change its type to a spin_lock.
I *think* that we might even be able to remove the lock because all its
current user seem to have their own protection.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 993ca6e0

drivers/iommu/amd_iommu.c

+7 −7
Original line number Diff line number Diff line
@@ -80,7 +80,7 @@ 
 */

#define AMD_IOMMU_PGSIZES	((~0xFFFUL) & ~(2ULL << 38))



static DEFINE_RWLOCK(amd_iommu_devtable_lock);

static DEFINE_SPINLOCK(amd_iommu_devtable_lock);

static DEFINE_SPINLOCK(pd_bitmap_lock);

static DEFINE_SPINLOCK(iommu_table_lock);
@@ -2097,9 +2097,9 @@ static int attach_device(struct device *dev, 
	}



skip_ats_check:

	write_lock_irqsave(&amd_iommu_devtable_lock, flags);

	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);

	ret = __attach_device(dev_data, domain);

	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);



	/*

	 * We might boot into a crash-kernel here. The crashed kernel
@@ -2149,9 +2149,9 @@ static void detach_device(struct device *dev) 
	domain   = dev_data->domain;



	/* lock device table */

	write_lock_irqsave(&amd_iommu_devtable_lock, flags);

	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);

	__detach_device(dev_data);

	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);



	if (!dev_is_pci(dev))

		return;
@@ -2814,7 +2814,7 @@ static void cleanup_domain(struct protection_domain *domain) 
	struct iommu_dev_data *entry;

	unsigned long flags;



	write_lock_irqsave(&amd_iommu_devtable_lock, flags);

	spin_lock_irqsave(&amd_iommu_devtable_lock, flags);



	while (!list_empty(&domain->dev_list)) {

		entry = list_first_entry(&domain->dev_list,
@@ -2822,7 +2822,7 @@ static void cleanup_domain(struct protection_domain *domain) 
		__detach_device(entry);

	}



	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

	spin_unlock_irqrestore(&amd_iommu_devtable_lock, flags);

}



static void protection_domain_free(struct protection_domain *domain)