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iommu/vt-d: Unnecessary spinlock for root table alloc and free

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The IOMMU root table is allocated and freed in the IOMMU initialization
code in static boot or hot-remove paths. There's no need for a spinlock.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20220706025524.2904370-5-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Lu Baolu 2022-07-12 08:08:55 +08:00 committed by Joerg Roedel
parent 8ac0b64b97
commit 2e1c8dafb8
1 changed files with 5 additions and 13 deletions
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18
drivers/iommu/intel/iommu.c
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@ -809,14 +809,12 @@ static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
static void free_context_table(struct intel_iommu *iommu)
{
int i;
unsigned long flags;
struct context_entry *context;
int i;
if (!iommu->root_entry)
return;
spin_lock_irqsave(&iommu->lock, flags);
if (!iommu->root_entry) {
goto out;
}
for (i = 0; i < ROOT_ENTRY_NR; i++) {
context = iommu_context_addr(iommu, i, 0, 0);
if (context)
@ -828,12 +826,10 @@ static void free_context_table(struct intel_iommu *iommu)
context = iommu_context_addr(iommu, i, 0x80, 0);
if (context)
free_pgtable_page(context);
}
free_pgtable_page(iommu->root_entry);
iommu->root_entry = NULL;
out:
spin_unlock_irqrestore(&iommu->lock, flags);
}
#ifdef CONFIG_DMAR_DEBUG
@ -1232,7 +1228,6 @@ static void domain_unmap(struct dmar_domain *domain, unsigned long start_pfn,
static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
struct root_entry *root;
unsigned long flags;
root = (struct root_entry *)alloc_pgtable_page(iommu->node);
if (!root) {
@ -1242,10 +1237,7 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
}
__iommu_flush_cache(iommu, root, ROOT_SIZE);
spin_lock_irqsave(&iommu->lock, flags);
iommu->root_entry = root;
spin_unlock_irqrestore(&iommu->lock, flags);
return 0;
}