[PATCH v4 1/2] drm/pagemap: dma-unmap pages before handling migration errors

[Matthew Brost <matthew.brost@intel.com>]

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@kernel.org>
Fixes: f86ad0ed620c ("drm/gpusvm, drm/pagemap: Move migration functionality to drm_pagemap")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
---
 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 097a900cf55d..6aa745682270 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c
@@ -1283,13 +1283,13 @@ 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);
 	drm_pagemap_retire_migrated_pages(src, 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);
@@ -1416,15 +1416,15 @@ static int __drm_pagemap_migrate_to_ram(struct vm_area_struct *vas,
 		goto err_finalize;
 
 err_finalize:
+	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);
 	drm_pagemap_retire_migrated_pages(migrate.src, npages);
 	migrate_vma_finalize(&migrate);
-	if (dev)
-		drm_pagemap_migrate_unmap_pages(dev, pagemap_addr, migrate.dst,
-						npages, DMA_FROM_DEVICE,
-						&state);
 err_free:
 	kvfree(buf);
 err_out:
-- 
2.34.1