FROMGIT: iommu: generalize the batched sync after map interface

For the upcoming IOVA-based DMA API we want to batch the
ops->iotlb_sync_map() call after mapping multiple IOVAs from
dma-iommu without having a scatterlist. Improve the API.

Add a wrapper for the map_sync as iommu_sync_map() so that callers
don't need to poke into the methods directly.

Formalize __iommu_map() into iommu_map_nosync() which requires the
caller to call iommu_sync_map() after all maps are completed.

Refactor the existing sanity checks from all the different layers
into iommu_map_nosync().

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Will Deacon <will@kernel.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
(cherry picked from commit 5c87cffe2d3853cfae61e9373ee98a0409839178
 https://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux.git)
Bug: 416098329
[Daniel: Adopted to commit 1a608d2b0d ("BACKPORT: FROMLIST: drivers/iommu:
Add deferred map_sg operations")]
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Change-Id: Iefa5c86c91bc5b89113a68798898a3b5c6896edc

drivers/iommu/iommu.c

@@ -2438,8 +2438,8 @@ out_set_count:
 	return pgsize;
 }
 
-static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
+int iommu_map_nosync(struct iommu_domain *domain, unsigned long iova,
-		       phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+		phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
 	const struct iommu_domain_ops *ops = domain->ops;
 	unsigned long orig_iova = iova;
@@ -2448,12 +2448,19 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	phys_addr_t orig_paddr = paddr;
 	int ret = 0;
 
+	might_sleep_if(gfpflags_allow_blocking(gfp));
+
 	if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
 		return -EINVAL;
 
 	if (WARN_ON(!ops->map_pages || domain->pgsize_bitmap == 0UL))
 		return -ENODEV;
 
+	/* Discourage passing strange GFP flags */
+	if (WARN_ON_ONCE(gfp & (__GFP_COMP | __GFP_DMA | __GFP_DMA32 |
+				__GFP_HIGHMEM)))
+		return -EINVAL;
+
 	/* find out the minimum page size supported */
 	min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
 
@@ -2501,31 +2508,27 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	return ret;
 }
 
+int iommu_sync_map(struct iommu_domain *domain, unsigned long iova, size_t size)
+{
+	const struct iommu_domain_ops *ops = domain->ops;
+
+	if (!ops->iotlb_sync_map)
+		return 0;
+	return ops->iotlb_sync_map(domain, iova, size);
+}
+
 int iommu_map(struct iommu_domain *domain, unsigned long iova,
 	      phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
-	const struct iommu_domain_ops *ops = domain->ops;
 	int ret;
 
-	might_sleep_if(gfpflags_allow_blocking(gfp));
+	ret = iommu_map_nosync(domain, iova, paddr, size, prot, gfp);
+	if (ret)
+		return ret;
 
-	/* Discourage passing strange GFP flags */
+	ret = iommu_sync_map(domain, iova, size);
-	if (WARN_ON_ONCE(gfp & (__GFP_COMP | __GFP_DMA | __GFP_DMA32 |
+	if (ret)
-				__GFP_HIGHMEM)))
+		iommu_unmap(domain, iova, size);
-		return -EINVAL;
-
-	ret = __iommu_map(domain, iova, paddr, size, prot, gfp);
-	if (ret == 0 && ops->iotlb_sync_map) {
-		ret = ops->iotlb_sync_map(domain, iova, size);
-		if (ret)
-			goto out_err;
-	}
-
-	return ret;
-
-out_err:
-	/* undo mappings already done */
-	iommu_unmap(domain, iova, size);
 
 	return ret;
 }
@@ -2651,13 +2654,6 @@ ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			   ops->consume_deferred_map_sg;
 	struct iommu_map_cookie_sg *cookie_sg;
 
-	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;
-
 	if (deferred_sg) {
 		cookie_sg = ops->alloc_cookie_sg(iova, prot, nents, gfp);
 		if (!cookie_sg) {
@@ -2674,9 +2670,8 @@ ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			if (deferred_sg)
 				ret = __iommu_add_sg(cookie_sg, iova + mapped, start, len);
 			else
-				ret = __iommu_map(domain, iova + mapped, start,
+				ret = iommu_map_nosync(domain, iova + mapped, start,
 						  len, prot, gfp);
-
 			if (ret)
 				goto out_err;
 
@@ -2710,11 +2705,10 @@ next:
 		}
 	}
 
-	if (ops->iotlb_sync_map) {
+	ret = iommu_sync_map(domain, iova, mapped);
-		ret = ops->iotlb_sync_map(domain, iova, mapped);
+	if (ret)
-		if (ret)
+		goto out_err;
-			goto out_err;
+
-	}
 	return mapped;
 
 out_err:

include/linux/iommu.h

@@ -821,6 +821,10 @@ extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
 		     phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
+int iommu_map_nosync(struct iommu_domain *domain, unsigned long iova,
+		phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
+int iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
+		size_t size);
 extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 			  size_t size);
 extern size_t iommu_unmap_fast(struct iommu_domain *domain,