linux/include/drm/drm_prime.h
Al Viro b2d4da31a1 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 <tzimmermann@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2024-09-10 13:44:30 -04:00

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C

/*
* Copyright © 2012 Red Hat
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* Copyright (c) 2009-2010, Code Aurora Forum.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Dave Airlie <airlied@redhat.com>
* Rob Clark <rob.clark@linaro.org>
*
*/
#ifndef __DRM_PRIME_H__
#define __DRM_PRIME_H__
#include <linux/mutex.h>
#include <linux/rbtree.h>
#include <linux/scatterlist.h>
/**
* struct drm_prime_file_private - per-file tracking for PRIME
*
* This just contains the internal &struct dma_buf and handle caches for each
* &struct drm_file used by the PRIME core code.
*/
struct drm_prime_file_private {
/* private: */
struct mutex lock;
struct rb_root dmabufs;
struct rb_root handles;
};
struct device;
struct dma_buf_export_info;
struct dma_buf;
struct dma_buf_attachment;
struct iosys_map;
enum dma_data_direction;
struct drm_device;
struct drm_gem_object;
struct drm_file;
/* core prime functions */
struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
struct dma_buf_export_info *exp_info);
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);
/* helper functions for exporting */
int drm_gem_map_attach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach);
void drm_gem_map_detach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach);
struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
enum dma_data_direction dir);
void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
struct sg_table *sgt,
enum dma_data_direction dir);
int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map);
void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map);
int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma);
struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
struct page **pages, unsigned int nr_pages);
struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
int flags);
unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt);
/* helper functions for importing */
struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
struct dma_buf *dma_buf,
struct device *attach_dev);
struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf);
void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg);
int drm_prime_sg_to_page_array(struct sg_table *sgt, struct page **pages,
int max_pages);
int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
int max_pages);
#endif /* __DRM_PRIME_H__ */