When testing with ethernet downloading, "EMEM address decode error" happens due to race condition between map() and unmap() functions.
This patch adds a spin lock to protect content within as->[count] and as->pts[pde] references, since a function call might be atomic. Signed-off-by: Nicolin Chen <[email protected]> --- drivers/iommu/tegra-smmu.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c index 3999ecb63cfa..236bc6d6d238 100644 --- a/drivers/iommu/tegra-smmu.c +++ b/drivers/iommu/tegra-smmu.c @@ -37,6 +37,7 @@ struct tegra_smmu { unsigned long *asids; struct mutex lock; + spinlock_t as_lock; struct list_head list; @@ -664,17 +665,23 @@ static int tegra_smmu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot, gfp_t gfp) { struct tegra_smmu_as *as = to_smmu_as(domain); + struct tegra_smmu *smmu = as->smmu; + unsigned long flags; dma_addr_t pte_dma; u32 pte_attrs; u32 *pte; + spin_lock_irqsave(&smmu->as_lock, flags); pte = as_get_pte(as, iova, &pte_dma); - if (!pte) + if (!pte) { + spin_unlock_irqrestore(&smmu->as_lock, flags); return -ENOMEM; + } /* If we aren't overwriting a pre-existing entry, increment use */ if (*pte == 0) tegra_smmu_pte_get_use(as, iova); + spin_unlock_irqrestore(&smmu->as_lock, flags); pte_attrs = SMMU_PTE_NONSECURE; @@ -694,6 +701,8 @@ static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size, struct iommu_iotlb_gather *gather) { struct tegra_smmu_as *as = to_smmu_as(domain); + struct tegra_smmu *smmu = as->smmu; + unsigned long flags; dma_addr_t pte_dma; u32 *pte; @@ -702,7 +711,10 @@ static size_t tegra_smmu_unmap(struct iommu_domain *domain, unsigned long iova, return 0; tegra_smmu_set_pte(as, iova, pte, pte_dma, 0); + + spin_lock_irqsave(&smmu->as_lock, flags); tegra_smmu_pte_put_use(as, iova); + spin_unlock_irqrestore(&smmu->as_lock, flags); return size; } @@ -1033,6 +1045,7 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev, INIT_LIST_HEAD(&smmu->groups); mutex_init(&smmu->lock); + spin_lock_init(&smmu->as_lock); smmu->regs = mc->regs; smmu->soc = soc; -- 2.17.1 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
