[PATCH v20 09/10] drm/shmem-helper: Switch drm_gem_shmem_vmap/vunmap to use pin/unpin

[Dmitry Osipenko <dmitry.osipenko@collabora.com>]

The vmapped pages shall be pinned in memory and previously get/put_pages()
were implicitly hard-pinning/unpinning the pages. This will no longer be
the case with addition of memory shrinker because pages_use_count > 0 won't
determine anymore whether pages are hard-pinned (they will be soft-pinned),
while the new pages_pin_count will do the hard-pinning. Switch the
vmap/vunmap() to use pin/unpin() functions in a preparation of addition
of the memory shrinker support to drm-shmem.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/gpu/drm/drm_gem_shmem_helper.c | 6 +++---
 include/drm/drm_gem_shmem_helper.h     | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 6fb96e790abd..84a196bbe44f 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -360,7 +360,7 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
 			return 0;
 		}
 
-		ret = drm_gem_shmem_get_pages_locked(shmem);
+		ret = drm_gem_shmem_pin_locked(shmem);
 		if (ret)
 			goto err_zero_use;
 
@@ -383,7 +383,7 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
 
 err_put_pages:
 	if (!drm_gem_is_imported(obj))
-		drm_gem_shmem_put_pages_locked(shmem);
+		drm_gem_shmem_unpin_locked(shmem);
 err_zero_use:
 	shmem->vmap_use_count = 0;
 
@@ -420,7 +420,7 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
 			return;
 
 		vunmap(shmem->vaddr);
-		drm_gem_shmem_put_pages_locked(shmem);
+		drm_gem_shmem_unpin_locked(shmem);
 	}
 
 	shmem->vaddr = NULL;
diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h
index 3a4be433d5f0..8b9bba87ae63 100644
--- a/include/drm/drm_gem_shmem_helper.h
+++ b/include/drm/drm_gem_shmem_helper.h
@@ -130,7 +130,7 @@ int drm_gem_shmem_madvise_locked(struct drm_gem_shmem_object *shmem, int madv);
 static inline bool drm_gem_shmem_is_purgeable(struct drm_gem_shmem_object *shmem)
 {
 	return (shmem->madv > 0) &&
-		!shmem->vmap_use_count && shmem->sgt &&
+		!refcount_read(&shmem->pages_pin_count) && shmem->sgt &&
 		!shmem->base.dma_buf && !drm_gem_is_imported(&shmem->base);
 }
 
-- 
2.49.0