iommu/amd: Optimize iommu_unmap_page for new fetch_pte interface

commit 71b390e9 upstream.

Now that fetch_pte returns the page-size of the pte, this
function can be optimized a lot.
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/iommu/amd_iommu.c

@@ -1479,8 +1479,8 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom,
 				      unsigned long bus_addr,
 				      unsigned long page_size)
 {
-	unsigned long long unmap_size, unmapped;
-	unsigned long pte_pgsize;
+	unsigned long long unmapped;
+	unsigned long unmap_size;
 	u64 *pte;
 
 	BUG_ON(!is_power_of_2(page_size));
@@ -1489,27 +1489,11 @@ static unsigned long iommu_unmap_page(struct protection_domain *dom,
 
 	while (unmapped < page_size) {
 
-		pte = fetch_pte(dom, bus_addr, &pte_pgsize);
+		pte = fetch_pte(dom, bus_addr, &unmap_size);
 
-		if (!pte) {
-			/*
-			 * No PTE for this address
-			 * move forward in 4kb steps
-			 */
-			unmap_size = PAGE_SIZE;
-		} else if (PM_PTE_LEVEL(*pte) == 0) {
-			/* 4kb PTE found for this address */
-			unmap_size = PAGE_SIZE;
-			*pte       = 0ULL;
-		} else {
-			int count, i;
-
-			/* Large PTE found which maps this address */
-			unmap_size = PTE_PAGE_SIZE(*pte);
+		if (pte) {
+			int i, count;
 
-			/* Only unmap from the first pte in the page */
-			if ((unmap_size - 1) & bus_addr)
-				break;
 			count = PAGE_SIZE_PTE_COUNT(unmap_size);
 			for (i = 0; i < count; i++)
 				pte[i] = 0ULL;