From 58188afeb727e0f73706f1460707bd3ba6ccc221 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Thu, 22 Jun 2017 16:53:57 +0100 Subject: [PATCH] iommu/arm-smmu-v3: Remove io-pgtable spinlock As for SMMUv2, take advantage of io-pgtable's newfound tolerance for concurrency. Unfortunately in this case the command queue lock remains a point of serialisation for the unmap path, but there may be a little more we can do to ameliorate that in future. Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- drivers/iommu/arm-smmu-v3.c | 33 ++++++--------------------------- 1 file changed, 6 insertions(+), 27 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index d50c8d4b9af9..884b1a49a52a 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -646,7 +646,6 @@ struct arm_smmu_domain { struct mutex init_mutex; /* Protects smmu pointer */ struct io_pgtable_ops *pgtbl_ops; - spinlock_t pgtbl_lock; enum arm_smmu_domain_stage stage; union { @@ -1414,7 +1413,6 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) } mutex_init(&smmu_domain->init_mutex); - spin_lock_init(&smmu_domain->pgtbl_lock); return &smmu_domain->domain; } @@ -1686,44 +1684,29 @@ out_unlock: static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot) { - int ret; - unsigned long flags; - struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); - struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; + struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; if (!ops) return -ENODEV; - spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags); - ret = ops->map(ops, iova, paddr, size, prot); - spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags); - return ret; + return ops->map(ops, iova, paddr, size, prot); } static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) { - size_t ret; - unsigned long flags; - struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); - struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; + struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; if (!ops) return 0; - spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags); - ret = ops->unmap(ops, iova, size); - spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags); - return ret; + return ops->unmap(ops, iova, size); } static phys_addr_t arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) { - phys_addr_t ret; - unsigned long flags; - struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); - struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; + struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; if (domain->type == IOMMU_DOMAIN_IDENTITY) return iova; @@ -1731,11 +1714,7 @@ arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova) if (!ops) return 0; - spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags); - ret = ops->iova_to_phys(ops, iova); - spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags); - - return ret; + return ops->iova_to_phys(ops, iova); } static struct platform_driver arm_smmu_driver; -- 2.20.1