From b2d4da31a1f40b05a61076efd4c79b88439003b7 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 2 Aug 2024 09:56:28 -0400 Subject: drm: new helper: drm_gem_prime_handle_to_dmabuf() Once something had been put into descriptor table, the only thing you can do with it is returning descriptor to userland - you can't withdraw it on subsequent failure exit, etc. You certainly can't count upon it staying in the same slot of descriptor table - another thread could've played with close(2)/dup2(2)/whatnot. drm_gem_prime_handle_to_fd() creates a dmabuf, allocates a descriptor and attaches dmabuf's file to it (the last two steps are done in dma_buf_fd()). That's nice when all you are going to do is passing a descriptor to userland. If you just need to work with the resulting object or have something else to be done that might fail, drm_gem_prime_handle_to_fd() is racy. The problem is analogous to one with anon_inode_getfd(), and solution is similar to what anon_inode_getfile() provides. Add drm_gem_prime_handle_to_dmabuf() - the "set dmabuf up" parts of drm_gem_prime_handle_to_fd() without the descriptor-related ones. Instead of inserting into descriptor table and returning the file descriptor it just returns the struct file. drm_gem_prime_handle_to_fd() becomes a wrapper for it. Other users will be introduced in the next commit. Acked-by: Thomas Zimmermann Signed-off-by: Al Viro Signed-off-by: Alex Deucher --- include/drm/drm_prime.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/drm') diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h index 2a1d01e5b56b..fa085c44d4ca 100644 --- a/include/drm/drm_prime.h +++ b/include/drm/drm_prime.h @@ -69,6 +69,9 @@ void drm_gem_dmabuf_release(struct dma_buf *dma_buf); int drm_gem_prime_fd_to_handle(struct drm_device *dev, struct drm_file *file_priv, int prime_fd, uint32_t *handle); +struct dma_buf *drm_gem_prime_handle_to_dmabuf(struct drm_device *dev, + struct drm_file *file_priv, uint32_t handle, + uint32_t flags); int drm_gem_prime_handle_to_fd(struct drm_device *dev, struct drm_file *file_priv, uint32_t handle, uint32_t flags, int *prime_fd); -- cgit v1.2.3