[PATCH v3 4/6] drm/pagemap: dma-unmap pages before handling migration errors

[Matthew Brost]

drm_pagemap_migrate_unmap_pages() relies on the pages array to determine
which pages require DMA unmapping. However,
drm_pagemap_migration_unlock_put_pages() clears the array as part of its
cleanup, leaving drm_pagemap_migrate_unmap_pages() with no valid page
information if it is called afterward.

Call drm_pagemap_migrate_unmap_pages() before
drm_pagemap_migration_unlock_put_pages() so the pages array remains
valid during DMA unmapping.

Reported-by: Sashiko <sashiko-bot@xxxxxxxxxx>
Fixes: f86ad0ed620c ("drm/gpusvm, drm/pagemap: Move migration functionality to drm_pagemap")
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Lorenzo Stoakes <ljs@xxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Liam R. Howlett <liam@xxxxxxxxxxxxx>
Cc: Nico Pache <nico.pache@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Dev Jain <dev.jain@xxxxxxx>
Cc: Barry Song <baohua@xxxxxxxxxx>
Cc: Lance Yang <lance.yang@xxxxxxxxx>
Cc: Usama Arif <usama.arif@xxxxxxxxx>
Cc: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>
Cc: Rakie Kim <rakie.kim@xxxxxx>
Cc: Byungchul Park <byungchul@xxxxxx>
Cc: Gregory Price <gourry@xxxxxxxxxx>
Cc: Ying Huang <ying.huang@xxxxxxxxxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Balbir Singh <balbirs@xxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: David Airlie <airlied@xxxxxxxxx>
Cc: Simona Vetter <simona@xxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Francois Dugast <francois.dugast@xxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
 drivers/gpu/drm/drm_pagemap.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
index 892b325fa99b..aef1fcea663d 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c
@@ -1175,12 +1175,12 @@ int drm_pagemap_evict_to_ram(struct drm_pagemap_devmem *devmem_allocation)
 		goto err_finalize;
 
 err_finalize:
+	drm_pagemap_migrate_unmap_pages(devmem_allocation->dev, pagemap_addr, dst, npages,
+					DMA_FROM_DEVICE, &state);
 	if (err)
 		drm_pagemap_migration_unlock_put_pages(npages, dst);
 	migrate_device_pages(src, dst, npages);
 	migrate_device_finalize(src, dst, npages);
-	drm_pagemap_migrate_unmap_pages(devmem_allocation->dev, pagemap_addr, dst, npages,
-					DMA_FROM_DEVICE, &state);
 
 err_free:
 	kvfree(buf);
@@ -1305,14 +1305,14 @@ static int __drm_pagemap_migrate_to_ram(struct vm_area_struct *vas,
 		goto err_finalize;
 
 err_finalize:
-	if (err)
-		drm_pagemap_migration_unlock_put_pages(npages, migrate.dst);
-	migrate_vma_pages(&migrate);
-	migrate_vma_finalize(&migrate);
 	if (dev)
 		drm_pagemap_migrate_unmap_pages(dev, pagemap_addr, migrate.dst,
 						npages, DMA_FROM_DEVICE,
 						&state);
+	if (err)
+		drm_pagemap_migration_unlock_put_pages(npages, migrate.dst);
+	migrate_vma_pages(&migrate);
+	migrate_vma_finalize(&migrate);
 err_free:
 	kvfree(buf);
 err_out:
-- 
2.34.1