[PATCH 1/3] drm/amdkfd: Fix error path at svm_migrate_copy_to_ram

From: Xiaogang Chen <[email protected]>

If page migration from device to sys ram fails for some reasons driver needs
release and unlock allocated system pages. To do that driver should use page
physical address, or pfn, then get struct page*. Current driver uses dma
address(for adev) that is not correct with IOMMU enabled, or even in general.

The patch releases and unlocks allocated system pages based on where migration
failed by struct page* of sys ram pages. Also dma_unmap correspodent system
ram pages at error path.

Signed-off-by: Xiaogang Chen <[email protected]>
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 46 ++++++++++++++++--------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 226e76ae0be7..aea82da5f575 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -258,15 +258,6 @@ svm_migrate_get_sys_page(struct vm_area_struct *vma, unsigned long addr)
 	return page;
 }
 
-static void svm_migrate_put_sys_page(unsigned long addr)
-{
-	struct page *page;
-
-	page = pfn_to_page(addr >> PAGE_SHIFT);
-	unlock_page(page);
-	put_page(page);
-}
-
 static unsigned long svm_migrate_successful_pages(struct migrate_vma *migrate)
 {
 	unsigned long mpages = 0;
@@ -591,9 +582,10 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 			dma_addr_t *scratch, u64 npages)
 {
 	struct device *dev = adev->dev;
-	u64 *src;
+	struct page *dpage = NULL;
 	dma_addr_t *dst;
-	struct page *dpage;
+	u64 *src;
+
 	u64 i = 0, j;
 	u64 addr;
 	int r = 0;
@@ -647,6 +639,7 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 		r = dma_mapping_error(dev, dst[i]);
 		if (r) {
 			dev_err(adev->dev, "%s: fail %d dma_map_page\n", __func__, r);
+			dst[i] = 0;
 			goto out_oom;
 		}
 
@@ -654,17 +647,40 @@ svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 				     dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));
 
 		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));
+
+		dpage = NULL;
 		j++;
 	}
 
-	r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
-					 FROM_VRAM_TO_RAM, mfence);
-
+	if (j > 0)
+		r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
+						 FROM_VRAM_TO_RAM, mfence);
 out_oom:
 	if (r) {
 		pr_debug("failed %d copy to ram\n", r);
+
+		/* first release current dpage when dma_map_page fail */
+		if (dpage) {
+			unlock_page(dpage);
+			put_page(dpage);
+			dpage = NULL;
+		}
+
+		/* release previous allocated sys pages and unmap dma address */
 		while (i--) {
-			svm_migrate_put_sys_page(dst[i]);
+
+			if (dst[i] && !dma_mapping_error(dev, dst[i])) {
+				dma_unmap_page(dev, dst[i], PAGE_SIZE,
+					       DMA_BIDIRECTIONAL);
+				dst[i] = 0;
+			}
+
+			dpage = migrate_pfn_to_page(migrate->dst[i]);
+			if (!dpage)
+				continue;
+
+			unlock_page(dpage);
+			put_page(dpage);
 			migrate->dst[i] = 0;
 		}
 	}
-- 
2.34.1