iommu: return full error code from iommu_map_sg[_atomic]()

Convert to ssize_t return code so the return code from __iommu_map()
can be returned all the way down through dma_iommu_map_sg().
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/iommu/iommu.c

@@ -2567,9 +2567,9 @@ size_t iommu_unmap_fast(struct iommu_domain *domain,
 }
 EXPORT_SYMBOL_GPL(iommu_unmap_fast);
 
-static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-			     struct scatterlist *sg, unsigned int nents, int prot,
-			     gfp_t gfp)
+static 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_ops *ops = domain->ops;
 	size_t len = 0, mapped = 0;
@@ -2610,19 +2610,18 @@ static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 	/* undo mappings already done */
 	iommu_unmap(domain, iova, mapped);
 
-	return 0;
-
+	return ret;
 }
 
-size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-		    struct scatterlist *sg, unsigned int nents, int prot)
+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);
 
-size_t iommu_map_sg_atomic(struct iommu_domain *domain, unsigned long iova,
+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);

include/linux/iommu.h

@@ -414,11 +414,11 @@ extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 extern size_t iommu_unmap_fast(struct iommu_domain *domain,
 			       unsigned long iova, size_t size,
 			       struct iommu_iotlb_gather *iotlb_gather);
-extern size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
-			   struct scatterlist *sg,unsigned int nents, int prot);
-extern size_t iommu_map_sg_atomic(struct iommu_domain *domain,
-				  unsigned long iova, struct scatterlist *sg,
-				  unsigned int nents, int prot);
+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);
 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);
@@ -679,18 +679,18 @@ static inline size_t iommu_unmap_fast(struct iommu_domain *domain,
 	return 0;
 }
 
-static inline size_t iommu_map_sg(struct iommu_domain *domain,
-				  unsigned long iova, struct scatterlist *sg,
-				  unsigned int nents, int prot)
+static inline ssize_t iommu_map_sg(struct iommu_domain *domain,
+				   unsigned long iova, struct scatterlist *sg,
+				   unsigned int nents, int prot)
 {
-	return 0;
+	return -ENODEV;
 }
 
-static inline size_t iommu_map_sg_atomic(struct iommu_domain *domain,
+static inline ssize_t iommu_map_sg_atomic(struct iommu_domain *domain,
 				  unsigned long iova, struct scatterlist *sg,
 				  unsigned int nents, int prot)
 {
-	return 0;
+	return -ENODEV;
 }
 
 static inline void iommu_flush_iotlb_all(struct iommu_domain *domain)