drm/shmem-helper: Switch drm_gem_shmem_vmap/vunmap to use pin/unpin

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>
Acked-by: Thomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-10-dmitry.osipenko@collabora.com

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index 6fb96e790abd24c4a37a36cfb64eee395de822be..84a196bbe44fad76801aaacd8bbf9d643439dbc9 100644 (file)
--- 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 3a4be433d5f0cf55712b76e32641a7773cea3b0a..8b9bba87ae63d8d598f8c7e15e02ed4b545984ae 100644 (file)
--- 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);
 }