From 0cc5fb4e87216320e5bc42603f735d666e101e43 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 14 May 2020 22:22:56 +0200 Subject: [PATCH] drm/shmem-helpers: Don't call get/put_pages on imported dma-buf in vmap MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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) Tested-by: Boris Brezillon Cc: Thomas Zimmermann Cc: Gerd Hoffmann Cc: Rob Herring Cc: Noralf Trønnes Acked-by: Thomas Zimmermann Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20200514202256.490926-1-daniel.vetter@ffwll.ch --- 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 3885854e85a9..0aac83ed9f5d 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; -- 2.34.1