iommu: Do not return error code for APIs with size_t return type

Currently, iommu_unmap, iommu_unmap_fast and iommu_map_sg return
size_t.  However, some of the return values are error codes (< 0),
which can be misinterpreted as large size. Therefore, returning size 0
instead to signify failure to map/unmap.

Cc: Joerg Roedel <joro@8bytes.org>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 11 insertions, 11 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 74788fdeb773..ecdeb045deef 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3050,7 +3050,7 @@ static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
         size_t unmap_size;
 
         if (domain->mode == PAGE_MODE_NONE)
-                return -EINVAL;
+                return 0;
 
         mutex_lock(&domain->api_lock);
         unmap_size = iommu_unmap_page(domain, iova, page_size);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 69fef991c651..d2aa23202bb9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1573,10 +1573,10 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 
         if (unlikely(ops->unmap == NULL ||
                      domain->pgsize_bitmap == 0UL))
-                return -ENODEV;
+                return 0;
 
         if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
-                return -EINVAL;
+                return 0;
 
         /* find out the minimum page size supported */
         min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
@@ -1589,7 +1589,7 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
         if (!IS_ALIGNED(iova | size, min_pagesz)) {
                 pr_err("unaligned: iova 0x%lx size 0x%zx min_pagesz 0x%x\n",
                        iova, size, min_pagesz);
-                return -EINVAL;
+                return 0;
         }
 
         pr_debug("unmap this: iova 0x%lx size 0x%zx\n", iova, size);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 41b8c5757859..19938ee6eb31 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -465,23 +465,23 @@ static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
         return -ENODEV;
 }
 
-static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
-                              size_t size)
+static inline size_t iommu_unmap(struct iommu_domain *domain,
+                                 unsigned long iova, size_t size)
 {
-        return -ENODEV;
+        return 0;
 }
 
-static inline int iommu_unmap_fast(struct iommu_domain *domain, unsigned long iova,
-                                   int gfp_order)
+static inline size_t iommu_unmap_fast(struct iommu_domain *domain,
+                                      unsigned long iova, int gfp_order)
 {
-        return -ENODEV;
+        return 0;
 }
 
 static inline size_t iommu_map_sg(struct iommu_domain *domain,
                                   unsigned long iova, struct scatterlist *sg,
                                   unsigned int nents, int prot)
 {
-        return -ENODEV;
+        return 0;
 }
 
 static inline void iommu_flush_tlb_all(struct iommu_domain *domain)