There's no direct harm, because for the shmem helpers these are noops
on imported buffers. The trouble is in the locks these take - I want
to change dma_buf_vmap locking, and so need to make sure that we only
ever take certain locks on one side of the dma-buf interface: Either
for exporters, or for importers.
v2: Change the control flow less compared to what's there (Thomas)
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Noralf Trønnes <noralf@xxxxxxxxxxx>
Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/gpu/drm/drm_gem_shmem_helper.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 2a70159d50ef..9540478e0434 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -252,15 +252,15 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
if (shmem->vmap_use_count++ > 0)
return shmem->vaddr;
- ret = drm_gem_shmem_get_pages(shmem);
- if (ret)
- goto err_zero_use;
-
if (obj->import_attach) {
shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);
} else {
pgprot_t prot = PAGE_KERNEL;
+ ret = drm_gem_shmem_get_pages(shmem);
+ if (ret)
+ goto err_zero_use;
+
if (!shmem->map_cached)
prot = pgprot_writecombine(prot);
shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
@@ -276,7 +276,8 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
return shmem->vaddr;
err_put_pages:
- drm_gem_shmem_put_pages(shmem);
+ if (!obj->import_attach)
+ drm_gem_shmem_put_pages(shmem);
err_zero_use:
shmem->vmap_use_count = 0;
--
2.26.2
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