iommu: Add a gfp parameter to iommu_map_sg()

Follow the pattern for iommu_map() and remove iommu_map_sg_atomic().

This allows __iommu_dma_alloc_noncontiguous() to use a GFP_KERNEL
allocation here, based on the provided gfp flags.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v3-76b587fe28df+6e3-iommu_map_gfp_jgg@nvidia.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/dma-iommu.c

@@ -833,7 +833,8 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
 			arch_dma_prep_coherent(sg_page(sg), sg->length);
 	}
 
-	ret = iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot);
+	ret = iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, ioprot,
+			   GFP_ATOMIC);
 	if (ret < 0 || ret < size)
 		goto out_free_sg;
 
@@ -1281,7 +1282,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	 * We'll leave any physical concatenation to the IOMMU driver's
 	 * implementation - it knows better than we do.
 	 */
-	ret = iommu_map_sg_atomic(domain, iova, sg, nents, prot);
+	ret = iommu_map_sg(domain, iova, sg, nents, prot, GFP_ATOMIC);
 	if (ret < 0 || ret < iova_len)
 		goto out_free_iova;
 

drivers/iommu/iommu.c

@@ -2470,9 +2470,9 @@ size_t iommu_unmap_fast(struct iommu_domain *domain,
 }
 EXPORT_SYMBOL_GPL(iommu_unmap_fast);
 
-static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-		struct scatterlist *sg, unsigned int nents, int prot,
-		gfp_t gfp)
+ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+		     struct scatterlist *sg, unsigned int nents, int prot,
+		     gfp_t gfp)
 {
 	const struct iommu_domain_ops *ops = domain->ops;
 	size_t len = 0, mapped = 0;
@@ -2480,6 +2480,13 @@ static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 	unsigned int i = 0;
 	int ret;
 
+	might_sleep_if(gfpflags_allow_blocking(gfp));
+
+	/* Discourage passing strange GFP flags */
+	if (WARN_ON_ONCE(gfp & (__GFP_COMP | __GFP_DMA | __GFP_DMA32 |
+				__GFP_HIGHMEM)))
+		return -EINVAL;
+
 	while (i <= nents) {
 		phys_addr_t s_phys = sg_phys(sg);
 
@@ -2519,21 +2526,8 @@ static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 
 	return ret;
 }
-
-ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-		     struct scatterlist *sg, unsigned int nents, int prot)
-{
-	might_sleep();
-	return __iommu_map_sg(domain, iova, sg, nents, prot, GFP_KERNEL);
-}
 EXPORT_SYMBOL_GPL(iommu_map_sg);
 
-ssize_t iommu_map_sg_atomic(struct iommu_domain *domain, unsigned long iova,
-		    struct scatterlist *sg, unsigned int nents, int prot)
-{
-	return __iommu_map_sg(domain, iova, sg, nents, prot, GFP_ATOMIC);
-}
-
 /**
  * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
  * @domain: the iommu domain where the fault has happened

include/linux/iommu.h

@@ -474,10 +474,8 @@ extern size_t iommu_unmap_fast(struct iommu_domain *domain,
 			       unsigned long iova, size_t size,
 			       struct iommu_iotlb_gather *iotlb_gather);
 extern ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-		struct scatterlist *sg, unsigned int nents, int prot);
-extern ssize_t iommu_map_sg_atomic(struct iommu_domain *domain,
-				   unsigned long iova, struct scatterlist *sg,
-				   unsigned int nents, int prot);
+			    struct scatterlist *sg, unsigned int nents,
+			    int prot, gfp_t gfp);
 extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
 extern void iommu_set_fault_handler(struct iommu_domain *domain,
 			iommu_fault_handler_t handler, void *token);
@@ -791,14 +789,7 @@ static inline size_t iommu_unmap_fast(struct iommu_domain *domain,
 
 static inline ssize_t iommu_map_sg(struct iommu_domain *domain,
 				   unsigned long iova, struct scatterlist *sg,
-				   unsigned int nents, int prot)
-{
-	return -ENODEV;
-}
-
-static inline ssize_t iommu_map_sg_atomic(struct iommu_domain *domain,
-				  unsigned long iova, struct scatterlist *sg,
-				  unsigned int nents, int prot)
+				   unsigned int nents, int prot, gfp_t gfp)
 {
 	return -ENODEV;
 }
@@ -1109,7 +1100,8 @@ iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid,
 static inline size_t iommu_map_sgtable(struct iommu_domain *domain,
 			unsigned long iova, struct sg_table *sgt, int prot)
 {
-	return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot);
+	return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot,
+			    GFP_KERNEL);
 }
 
 #ifdef CONFIG_IOMMU_DEBUGFS