iommu/arm-smmu: Check the return type of map_sg and take appropriate action

We cannot call unmap directly if the map_sg fails partially as the tlb
invalidate functions need to enable/prepare clocks, which require
non-atomic context. Let map_sg return the failure and handle this when
we are out of the atomic context.

Change-Id: I6401c1e281850aeda27e32524cae34324045f762
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 435ce03..67c3d70 100644 (file)
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -2073,10 +2073,13 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
        return ret;
 }
 
+static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
+                            size_t size);
 static size_t arm_smmu_map_sg(struct iommu_domain *domain, unsigned long iova,
                           struct scatterlist *sg, unsigned int nents, int prot)
 {
        int ret;
+       size_t size;
        unsigned long flags;
        struct arm_smmu_domain *smmu_domain = domain->priv;
        struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;
@@ -2085,12 +2088,15 @@ static size_t arm_smmu_map_sg(struct iommu_domain *domain, unsigned long iova,
                return -ENODEV;
 
        spin_lock_irqsave(&smmu_domain->pgtbl_lock, flags);
-       ret = ops->map_sg(ops, iova, sg, nents, prot);
+       ret = ops->map_sg(ops, iova, sg, nents, prot, &size);
        spin_unlock_irqrestore(&smmu_domain->pgtbl_lock, flags);
 
-       if (ret)
+       if (ret) {
                if (arm_smmu_assign_table(smmu_domain))
                        return 0;
+       } else {
+               arm_smmu_unmap(domain, iova, size);
+       }
 
        return ret;
 }

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 83cd01d..6274edc 100644 (file)
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -459,7 +459,7 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
 
 static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
                           struct scatterlist *sg, unsigned int nents,
-                          int iommu_prot)
+                          int iommu_prot, size_t *size)
 {
        struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
        arm_lpae_iopte *ptep = data->pgd;
@@ -469,7 +469,6 @@ static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
        size_t mapped = 0;
        int i, ret;
        unsigned int min_pagesz;
-       unsigned long orig_iova = iova;
        struct map_state ms;
 
        /* If no access, then nothing to do */
@@ -529,10 +528,8 @@ static int arm_lpae_map_sg(struct io_pgtable_ops *ops, unsigned long iova,
        return mapped;
 
 out_err:
-       /* undo mappings already done */
-       if (mapped)
-               ops->unmap(ops, orig_iova, mapped);
-
+       /* Return the size of the partial mapping so that they can be undone */
+       *size = mapped;
        return 0;
 }
 

diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index c1c656b..f74f148 100644 (file)
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h
@@ -77,6 +77,8 @@ struct io_pgtable_cfg {
  * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
  *
  * @map:          Map a physically contiguous memory region.
+ * @map_sg:      Map a scatterlist. The size parameter contains the size
+ *               of the partial mapping in case of failure.
  * @unmap:        Unmap a physically contiguous memory region.
  * @iova_to_phys: Translate iova to physical address.
  *
@@ -87,7 +89,8 @@ struct io_pgtable_ops {
        int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
                   phys_addr_t paddr, size_t size, int prot);
        int (*map_sg)(struct io_pgtable_ops *ops, unsigned long iova,
-                        struct scatterlist *sg, unsigned int nents, int prot);
+                        struct scatterlist *sg, unsigned int nents,
+                        int prot, size_t *size);
        size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
                        size_t size);
        phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,