[PATCH 5.18 16/88] nouveau/svm: Fix to migrate all requested pages

[Greg Kroah-Hartman]

From: Alistair Popple <apopple@xxxxxxxxxx>

commit 66cee9097e2b74ff3c8cc040ce5717c521a0c3fa upstream.

Users may request that pages from an OpenCL SVM allocation be migrated
to the GPU with clEnqueueSVMMigrateMem(). In Nouveau this will call into
nouveau_dmem_migrate_vma() to do the migration. If the total range to be
migrated exceeds SG_MAX_SINGLE_ALLOC the pages will be migrated in
chunks of size SG_MAX_SINGLE_ALLOC. However a typo in updating the
starting address means that only the first chunk will get migrated.

Fix the calculation so that the entire range will get migrated if
possible.

Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Fixes: e3d8b0890469 ("drm/nouveau/svm: map pages after migration")
Reviewed-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220720062745.960701-1-apopple@xxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v5.8+
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/nouveau/nouveau_dmem.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -680,7 +680,11 @@ nouveau_dmem_migrate_vma(struct nouveau_
 		goto out_free_dma;
 
 	for (i = 0; i < npages; i += max) {
-		args.end = start + (max << PAGE_SHIFT);
+		if (args.start + (max << PAGE_SHIFT) > end)
+			args.end = end;
+		else
+			args.end = args.start + (max << PAGE_SHIFT);
+
 		ret = migrate_vma_setup(&args);
 		if (ret)
 			goto out_free_pfns;