/*
* Copyright © 2012 Red Hat
*
* 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 <[email protected]>
* Rob Clark <[email protected]>
*
*/
#include <linux/export.h>
#include <linux/dma-buf.h>
#include <linux/rbtree.h>
#include <linux/module.h>
#include <drm/drm.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem.h>
#include <drm/drm_prime.h>
#include "drm_internal.h"
MODULE_IMPORT_NS(DMA_BUF);
/**
* DOC: overview and lifetime rules
*
* Similar to GEM global names, PRIME file descriptors are also used to share
* buffer objects across processes. They offer additional security: as file
* descriptors must be explicitly sent over UNIX domain sockets to be shared
* between applications, they can't be guessed like the globally unique GEM
* names.
*
* Drivers that support the PRIME API implement the drm_gem_object_funcs.export
* and &drm_driver.gem_prime_import hooks. &dma_buf_ops implementations for
* drivers are all individually exported for drivers which need to overwrite
* or reimplement some of them.
*
* Reference Counting for GEM Drivers
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* On the export the &dma_buf holds a reference to the exported buffer object,
* usually a &drm_gem_object. It takes this reference in the PRIME_HANDLE_TO_FD
* IOCTL, when it first calls &drm_gem_object_funcs.export
* and stores the exporting GEM object in the &dma_buf.priv field. This
* reference needs to be released when the final reference to the &dma_buf
* itself is dropped and its &dma_buf_ops.release function is called. For
* GEM-based drivers, the &dma_buf should be exported using
* drm_gem_dmabuf_export() and then released by drm_gem_dmabuf_release().
*
* Thus the chain of references always flows in one direction, avoiding loops:
* importing GEM object -> dma-buf -> exported GEM bo. A further complication
* are the lookup caches for import and export. These are required to guarantee
* that any given object will always have only one unique userspace handle. This
* is required to allow userspace to detect duplicated imports, since some GEM
* drivers do fail command submissions if a given buffer object is listed more
* than once. These import and export caches in &drm_prime_file_private only
* retain a weak reference, which is cleaned up when the corresponding object is
* released.
*
* Self-importing: If userspace is using PRIME as a replacement for flink then
* it will get a fd->handle request for a GEM object that it created. Drivers
* should detect this situation and return back the underlying object from the
* dma-buf private. For GEM based drivers this is handled in
* drm_gem_prime_import() already.
*/
struct drm_prime_member {
struct dma_buf *dma_buf;
uint32_t handle;
struct rb_node dmabuf_rb;
struct rb_node handle_rb;
};
static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv,
struct dma_buf *dma_buf, uint32_t handle)
{
struct drm_prime_member *member;
struct rb_node **p, *rb;
member = kmalloc(sizeof(*member), GFP_KERNEL);
if (!member)
return -ENOMEM;
get_dma_buf(dma_buf);
member->dma_buf = dma_buf;
member->handle = handle;
rb = NULL;
p = &prime_fpriv->dmabufs.rb_node;
while (*p) {
struct drm_prime_member *pos;
rb = *p;
pos = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
if (dma_buf > pos->dma_buf)
p = &rb->rb_right;
else
p = &rb->rb_left;
}
rb_link_node(&member->dmabuf_rb, rb, p);
rb_insert_color(&member->dmabuf_rb, &prime_fpriv->dmabufs);
rb = NULL;
p = &prime_fpriv->handles.rb_node;
while (*p) {
struct drm_prime_member *pos;
rb = *p;
pos = rb_entry(rb, struct drm_prime_member, handle_rb);
if (handle > pos->handle)
p = &rb->rb_right;
else
p = &rb->rb_left;
}
rb_link_node(&member->handle_rb, rb, p);
rb_insert_color(&member->handle_rb, &prime_fpriv->handles);
return 0;
}
static struct dma_buf *drm_prime_lookup_buf_by_handle(struct drm_prime_file_private *prime_fpriv,
uint32_t handle)
{
struct rb_node *rb;
rb = prime_fpriv->handles.rb_node;
while (rb) {
struct drm_prime_member *member;
member = rb_entry(rb, struct drm_prime_member, handle_rb);
if (member->handle == handle)
return member->dma_buf;
else if (member->handle < handle)
rb = rb->rb_right;
else
rb = rb->rb_left;
}
return NULL;
}
static int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv,
struct dma_buf *dma_buf,
uint32_t *handle)
{
struct rb_node *rb;
rb = prime_fpriv->dmabufs.rb_node;
while (rb) {
struct drm_prime_member *member;
member = rb_entry(rb, struct drm_prime_member, dmabuf_rb);
if (member->dma_buf == dma_buf) {
*handle = member->handle;
return 0;
} else if (member->dma_buf < dma_buf) {
rb = rb->rb_right;
} else {
rb = rb->rb_left;
}
}
return -ENOENT;
}
void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv,
uint32_t handle)
{
struct rb_node *rb;
mutex_lock(&prime_fpriv->lock);
rb = prime_fpriv->handles.rb_node;
while (rb) {
struct drm_prime_member *member;
member = rb_entry(rb, struct drm_prime_member, handle_rb);
if (member->handle == handle) {
rb_erase(&member->handle_rb, &prime_fpriv->handles);
rb_erase(&member->dmabuf_rb, &prime_fpriv->dmabufs);
dma_buf_put(member->dma_buf);
kfree(member);
break;
} else if (member->handle < handle) {
rb = rb->rb_right;
} else {
rb = rb->rb_left;
}
}
mutex_unlock(&prime_fpriv->lock);
}
void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv)
{
mutex_init(&prime_fpriv->lock);
prime_fpriv->dmabufs = RB_ROOT;
prime_fpriv->handles = RB_ROOT;
}
void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv)
{
/* by now drm_gem_release should've made sure the list is empty */
WARN_ON(!RB_EMPTY_ROOT(&prime_fpriv->dmabufs));
}
/**
* drm_gem_dmabuf_export - &dma_buf export implementation for GEM
* @dev: parent device for the exported dmabuf
* @exp_info: the export information used by dma_buf_export()
*
* This wraps dma_buf_export() for use by generic GEM drivers that are using
* drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
* a reference to the &drm_device and the exported &drm_gem_object (stored in
* &dma_buf_export_info.priv) which is released by drm_gem_dmabuf_release().
*
* Returns the new dmabuf.
*/
struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
struct dma_buf_export_info *exp_info)
{
struct drm_gem_object *obj = exp_info->priv;
struct dma_buf *dma_buf;
dma_buf = dma_buf_export(exp_info);
if (IS_ERR(dma_buf))
return dma_buf;
drm_dev_get(dev);
drm_gem_object_get(obj);
dma_buf->file->f_mapping = obj->dev->anon_inode->i_mapping;
return dma_buf;
}
EXPORT_SYMBOL(drm_gem_dmabuf_export);
/**
* drm_gem_dmabuf_release - &dma_buf release implementation for GEM
* @dma_buf: buffer to be released
*
* Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
* must use this in their &dma_buf_ops structure as the release callback.
* drm_gem_dmabuf_release() should be used in conjunction with
* drm_gem_dmabuf_export().
*/
void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
{
struct drm_gem_object *obj = dma_buf->priv;
struct drm_device *dev = obj->dev;
/* drop the reference on the export fd holds */
drm_gem_object_put(obj);
drm_dev_put(dev);
}
EXPORT_SYMBOL(drm_gem_dmabuf_release);
/**
* drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
* @dev: drm_device to import into
* @file_priv: drm file-private structure
* @prime_fd: fd id of the dma-buf which should be imported
* @handle: pointer to storage for the handle of the imported buffer object
*
* This is the PRIME import function which must be used mandatorily by GEM
* drivers to ensure correct lifetime management of the underlying GEM object.
* The actual importing of GEM object from the dma-buf is done through the
* &drm_driver.gem_prime_import driver callback.
*
* Returns 0 on success or a negative error code on failure.
*/
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 *dma_buf;
struct drm_gem_object *obj;
int ret;
dma_buf = dma_buf_get(prime_fd);
if (IS_ERR(dma_buf))
return PTR_ERR(dma_buf);
mutex_lock(&file_priv->prime.lock);
ret = drm_prime_lookup_buf_handle(&file_priv->prime,
dma_buf, handle);
if (ret == 0)
goto out_put;
/* never seen this one, need to import */
mutex_lock(&dev->object_name_lock);
if (dev->driver->gem_prime_import)
obj = dev->driver->gem_prime_import(dev, dma_buf);
else
obj = drm_gem_prime_import(dev, dma_buf);
if (IS_ERR(obj)) {
ret = PTR_ERR(obj);
goto out_unlock;
}
if (obj->dma_buf) {
WARN_ON(obj->dma_buf != dma_buf);
} else {
obj->dma_buf = dma_buf;
get_dma_buf(dma_buf);
}
/* _handle_create_tail unconditionally unlocks dev->object_name_lock. */
ret = drm_gem_handle_create_tail(file_priv, obj, handle);
drm_gem_object_put(obj);
if (ret)
goto out_put;
ret = drm_prime_add_buf_handle(&file_priv->prime,
dma_buf, *handle);
mutex_unlock(&file_priv->prime.lock);
if (ret)
goto fail;
dma_buf_put(dma_buf);
return 0;
fail:
/* hmm, if driver attached, we are relying on the free-object path
* to detach.. which seems ok..
*/
drm_gem_handle_delete(file_priv, *handle);
dma_buf_put(dma_buf);
return ret;
out_unlock:
mutex_unlock(&dev->object_name_lock);
out_put:
mutex_unlock(&file_priv->prime.lock);
dma_buf_put(dma_buf);
return ret;
}
EXPORT_SYMBOL(drm_gem_prime_fd_to_handle);
int drm_prime_fd_to_handle_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_prime_handle *args = data;
if (dev->driver->prime_fd_to_handle) {
return dev->driver->prime_fd_to_handle(dev, file_priv, args->fd,
&args->handle);
}
return drm_gem_prime_fd_to_handle(dev, file_priv, args->fd, &args->handle);
}
static struct dma_buf *export_and_register_object(struct drm_device *dev,
struct drm_gem_object *obj,
uint32_t flags)
{
struct dma_buf *dmabuf;
/* prevent races with concurrent gem_close. */
if (obj->handle_count == 0) {
dmabuf = ERR_PTR(-ENOENT);
return dmabuf;
}
if (obj->funcs && obj->funcs->export)
dmabuf = obj->funcs->export(obj, flags);
else
dmabuf = drm_gem_prime_export(obj, flags);
if (IS_ERR(dmabuf)) {
/* normally the created dma-buf takes ownership of the ref,
* but if that fails then drop the ref
*/
return dmabuf;
}
/*
* Note that callers do not need to clean up the export cache
* since the check for obj->handle_count guarantees that someone
* will clean it up.
*/
obj->dma_buf = dmabuf;
get_dma_buf(obj->dma_buf);
return dmabuf;
}
/**
* drm_gem_prime_handle_to_dmabuf - PRIME export function for GEM drivers
* @dev: dev to export the buffer from
* @file_priv: drm file-private structure
* @handle: buffer handle to export
* @flags: flags like DRM_CLOEXEC
*
* This is the PRIME export function which must be used mandatorily by GEM
* drivers to ensure correct lifetime management of the underlying GEM object.
* The actual exporting from GEM object to a dma-buf is done through the
* &drm_gem_object_funcs.export callback.
*
* Unlike drm_gem_prime_handle_to_fd(), it returns the struct dma_buf it
* has created, without attaching it to any file descriptors. The difference
* between those two is similar to that between anon_inode_getfile() and
* anon_inode_getfd(); insertion into descriptor table is something you
* can not revert if any cleanup is needed, so the descriptor-returning
* variants should only be used when you are past the last failure exit
* and the only thing left is passing the new file descriptor to userland.
* When all you need is the object itself or when you need to do something
* else that might fail, use that one instead.
*/
struct dma_buf *drm_gem_prime_handle_to_dmabuf(struct drm_device *dev,
struct drm_file *file_priv, uint32_t handle,
uint32_t flags)
{
struct drm_gem_object *obj;
int ret = 0;
struct dma_buf *dmabuf;
mutex_lock(&file_priv->prime.lock);
obj = drm_gem_object_lookup(file_priv, handle);
if (!obj) {
dmabuf = ERR_PTR(-ENOENT);
goto out_unlock;
}
dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle);
if (dmabuf) {
get_dma_buf(dmabuf);
goto out;
}
mutex_lock(&dev->object_name_lock);
/* re-export the original imported object */
if (obj->import_attach) {
dmabuf = obj->import_attach->dmabuf;
get_dma_buf(dmabuf);
goto out_have_obj;
}
if (obj->dma_buf) {
get_dma_buf(obj->dma_buf);
dmabuf = obj->dma_buf;
goto out_have_obj;
}
dmabuf = export_and_register_object(dev, obj, flags);
if (IS_ERR(dmabuf)) {
/* normally the created dma-buf takes ownership of the ref,
* but if that fails then drop the ref
*/
mutex_unlock(&dev->object_name_lock);
goto out;
}
out_have_obj:
/*
* If we've exported this buffer then cheat and add it to the import list
* so we get the correct handle back. We must do this under the
* protection of dev->object_name_lock to ensure that a racing gem close
* ioctl doesn't miss to remove this buffer handle from the cache.
*/
ret = drm_prime_add_buf_handle(&file_priv->prime,
dmabuf, handle);
mutex_unlock(&dev->object_name_lock);
if (ret) {
dma_buf_put(dmabuf);
dmabuf = ERR_PTR(ret);
}
out:
drm_gem_object_put(obj);
out_unlock:
mutex_unlock(&file_priv->prime.lock);
return dmabuf;
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_dmabuf);
/**
* drm_gem_prime_handle_to_fd - PRIME export function for GEM drivers
* @dev: dev to export the buffer from
* @file_priv: drm file-private structure
* @handle: buffer handle to export
* @flags: flags like DRM_CLOEXEC
* @prime_fd: pointer to storage for the fd id of the create dma-buf
*
* This is the PRIME export function which must be used mandatorily by GEM
* drivers to ensure correct lifetime management of the underlying GEM object.
* The actual exporting from GEM object to a dma-buf is done through the
* &drm_gem_object_funcs.export callback.
*/
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)
{
struct dma_buf *dmabuf;
int fd = get_unused_fd_flags(flags);
if (fd < 0)
return fd;
dmabuf = drm_gem_prime_handle_to_dmabuf(dev, file_priv, handle, flags);
if (IS_ERR(dmabuf)) {
put_unused_fd(fd);
return PTR_ERR(dmabuf);
}
fd_install(fd, dmabuf->file);
*prime_fd = fd;
return 0;
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
int drm_prime_handle_to_fd_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_prime_handle *args = data;
/* check flags are valid */
if (args->flags & ~(DRM_CLOEXEC | DRM_RDWR))
return -EINVAL;
if (dev->driver->prime_handle_to_fd) {
return dev->driver->prime_handle_to_fd(dev, file_priv,
args->handle, args->flags,
&args->fd);
}
return drm_gem_prime_handle_to_fd(dev, file_priv, args->handle,
args->flags, &args->fd);
}
/**
* DOC: PRIME Helpers
*
* Drivers can implement &drm_gem_object_funcs.export and
* &drm_driver.gem_prime_import in terms of simpler APIs by using the helper
* functions drm_gem_prime_export() and drm_gem_prime_import(). These functions
* implement dma-buf support in terms of some lower-level helpers, which are
* again exported for drivers to use individually:
*
* Exporting buffers
* ~~~~~~~~~~~~~~~~~
*
* Optional pinning of buffers is handled at dma-buf attach and detach time in
* drm_gem_map_attach() and drm_gem_map_detach(). Backing storage itself is
* handled by drm_gem_map_dma_buf() and drm_gem_unmap_dma_buf(), which relies on
* &drm_gem_object_funcs.get_sg_table. If &drm_gem_object_funcs.get_sg_table is
* unimplemented, exports into another device are rejected.
*
* For kernel-internal access there's drm_gem_dmabuf_vmap() and
* drm_gem_dmabuf_vunmap(). Userspace mmap support is provided by
* drm_gem_dmabuf_mmap().
*
* Note that these export helpers can only be used if the underlying backing
* storage is fully coherent and either permanently pinned, or it is safe to pin
* it indefinitely.
*
* FIXME: The underlying helper functions are named rather inconsistently.
*
* Importing buffers
* ~~~~~~~~~~~~~~~~~
*
* Importing dma-bufs using drm_gem_prime_import() relies on
* &drm_driver.gem_prime_import_sg_table.
*
* Note that similarly to the export helpers this permanently pins the
* underlying backing storage. Which is ok for scanout, but is not the best
* option for sharing lots of buffers for rendering.
*/
/**
* drm_gem_map_attach - dma_buf attach implementation for GEM
* @dma_buf: buffer to attach device to
* @attach: buffer attachment data
*
* Calls &drm_gem_object_funcs.pin for device specific handling. This can be
* used as the &dma_buf_ops.attach callback. Must be used together with
* drm_gem_map_detach().
*
* Returns 0 on success, negative error code on failure.
*/
int drm_gem_map_attach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach)
{
struct drm_gem_object *obj = dma_buf->priv;
/*
* drm_gem_map_dma_buf() requires obj->get_sg_table(), but drivers
* that implement their own ->map_dma_buf() do not.
*/
if (dma_buf->ops->map_dma_buf == drm_gem_map_dma_buf &&
!obj->funcs->get_sg_table)
return -ENOSYS;
return drm_gem_pin(obj);
}
EXPORT_SYMBOL(drm_gem_map_attach);
/**
* drm_gem_map_detach - dma_buf detach implementation for GEM
* @dma_buf: buffer to detach from
* @attach: attachment to be detached
*
* Calls &drm_gem_object_funcs.pin for device specific handling. Cleans up
* &dma_buf_attachment from drm_gem_map_attach(). This can be used as the
* &dma_buf_ops.detach callback.
*/
void drm_gem_map_detach(struct dma_buf *dma_buf,
struct dma_buf_attachment *attach)
{
struct drm_gem_object *obj = dma_buf->priv;
drm_gem_unpin(obj);
}
EXPORT_SYMBOL(drm_gem_map_detach);
/**
* drm_gem_map_dma_buf - map_dma_buf implementation for GEM
* @attach: attachment whose scatterlist is to be returned
* @dir: direction of DMA transfer
*
* Calls &drm_gem_object_funcs.get_sg_table and then maps the scatterlist. This
* can be used as the &dma_buf_ops.map_dma_buf callback. Should be used together
* with drm_gem_unmap_dma_buf().
*
* Returns:sg_table containing the scatterlist to be returned; returns ERR_PTR
* on error. May return -EINTR if it is interrupted by a signal.
*/
struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
enum dma_data_direction dir)
{
struct drm_gem_object *obj = attach->dmabuf->priv;
struct sg_table *sgt;
int ret;
if (WARN_ON(dir == DMA_NONE))
return ERR_PTR(-EINVAL);
if (WARN_ON(!obj->funcs->get_sg_table))
return ERR_PTR(-ENOSYS);
sgt = obj->funcs->get_sg_table(obj);
if (IS_ERR(sgt))
return sgt;
ret = dma_map_sgtable(attach->dev, sgt, dir,
DMA_ATTR_SKIP_CPU_SYNC);
if (ret) {
sg_free_table(sgt);
kfree(sgt);
sgt = ERR_PTR(ret);
}
return sgt;
}
EXPORT_SYMBOL(drm_gem_map_dma_buf);
/**
* drm_gem_unmap_dma_buf - unmap_dma_buf implementation for GEM
* @attach: attachment to unmap buffer from
* @sgt: scatterlist info of the buffer to unmap
* @dir: direction of DMA transfer
*
* This can be used as the &dma_buf_ops.unmap_dma_buf callback.
*/
void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
struct sg_table *sgt,
enum dma_data_direction dir)
{
if (!sgt)
return;
dma_unmap_sgtable(attach->dev, sgt, dir, DMA_ATTR_SKIP_CPU_SYNC);
sg_free_table(sgt);
kfree(sgt);
}
EXPORT_SYMBOL(drm_gem_unmap_dma_buf);
/**
* drm_gem_dmabuf_vmap - dma_buf vmap implementation for GEM
* @dma_buf: buffer to be mapped
* @map: the virtual address of the buffer
*
* Sets up a kernel virtual mapping. This can be used as the &dma_buf_ops.vmap
* callback. Calls into &drm_gem_object_funcs.vmap for device specific handling.
* The kernel virtual address is returned in map.
*
* Returns 0 on success or a negative errno code otherwise.
*/
int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct iosys_map *map)
{
struct drm_gem_object *obj = dma_buf->priv;
return drm_gem_vmap(obj, map);
}
EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
/**
* drm_gem_dmabuf_vunmap - dma_buf vunmap implementation for GEM
* @dma_buf: buffer to be unmapped
* @map: the virtual address of the buffer
*
* Releases a kernel virtual mapping. This can be used as the
* &dma_buf_ops.vunmap callback. Calls into &drm_gem_object_funcs.vunmap for device specific handling.
*/
void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct iosys_map *map)
{
struct drm_gem_object *obj = dma_buf->priv;
drm_gem_vunmap(obj, map);
}
EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
/**
* drm_gem_prime_mmap - PRIME mmap function for GEM drivers
* @obj: GEM object
* @vma: Virtual address range
*
* This function sets up a userspace mapping for PRIME exported buffers using
* the same codepath that is used for regular GEM buffer mapping on the DRM fd.
* The fake GEM offset is added to vma->vm_pgoff and &drm_driver->fops->mmap is
* called to set up the mapping.
*/
int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
{
struct drm_file *priv;
struct file *fil;
int ret;
/* Add the fake offset */
vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);
if (obj->funcs && obj->funcs->mmap) {
vma->vm_ops = obj->funcs->vm_ops;
drm_gem_object_get(obj);
ret = obj->funcs->mmap(obj, vma);
if (ret) {
drm_gem_object_put(obj);
return ret;
}
vma->vm_private_data = obj;
return 0;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
fil = kzalloc(sizeof(*fil), GFP_KERNEL);
if (!priv || !fil) {
ret = -ENOMEM;
goto out;
}
/* Used by drm_gem_mmap() to lookup the GEM object */
priv->minor = obj->dev->primary;
fil->private_data = priv;
ret = drm_vma_node_allow(&obj->vma_node, priv);
if (ret)
goto out;
ret = obj->dev->driver->fops->mmap(fil, vma);
drm_vma_node_revoke(&obj->vma_node, priv);
out:
kfree(priv);
kfree(fil);
return ret;
}
EXPORT_SYMBOL(drm_gem_prime_mmap);
/**
* drm_gem_dmabuf_mmap - dma_buf mmap implementation for GEM
* @dma_buf: buffer to be mapped
* @vma: virtual address range
*
* Provides memory mapping for the buffer. This can be used as the
* &dma_buf_ops.mmap callback. It just forwards to drm_gem_prime_mmap().
*
* Returns 0 on success or a negative error code on failure.
*/
int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma)
{
struct drm_gem_object *obj = dma_buf->priv;
return drm_gem_prime_mmap(obj, vma);
}
EXPORT_SYMBOL(drm_gem_dmabuf_mmap);
static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
.cache_sgt_mapping = true,
.attach = drm_gem_map_attach,
.detach = drm_gem_map_detach,
.map_dma_buf = drm_gem_map_dma_buf,
.unmap_dma_buf = drm_gem_unmap_dma_buf,
.release = drm_gem_dmabuf_release,
.mmap = drm_gem_dmabuf_mmap,
.vmap = drm_gem_dmabuf_vmap,
.vunmap = drm_gem_dmabuf_vunmap,
};
/**
* drm_prime_pages_to_sg - converts a page array into an sg list
* @dev: DRM device
* @pages: pointer to the array of page pointers to convert
* @nr_pages: length of the page vector
*
* This helper creates an sg table object from a set of pages
* the driver is responsible for mapping the pages into the
* importers address space for use with dma_buf itself.
*
* This is useful for implementing &drm_gem_object_funcs.get_sg_table.
*/
struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
struct page **pages, unsigned int nr_pages)
{
struct sg_table *sg;
size_t max_segment = 0;
int err;
sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
if (!sg)
return ERR_PTR(-ENOMEM);
if (dev)
max_segment = dma_max_mapping_size(dev->dev);
if (max_segment == 0)
max_segment = UINT_MAX;
err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
(unsigned long)nr_pages << PAGE_SHIFT,
max_segment, GFP_KERNEL);
if (err) {
kfree(sg);
sg = ERR_PTR(err);
}
return sg;
}
EXPORT_SYMBOL(drm_prime_pages_to_sg);
/**
* drm_prime_get_contiguous_size - returns the contiguous size of the buffer
* @sgt: sg_table describing the buffer to check
*
* This helper calculates the contiguous size in the DMA address space
* of the buffer described by the provided sg_table.
*
* This is useful for implementing
* &drm_gem_object_funcs.gem_prime_import_sg_table.
*/
unsigned long drm_prime_get_contiguous_size(struct sg_table *sgt)
{
dma_addr_t expected = sg_dma_address(sgt->sgl);
struct scatterlist *sg;
unsigned long size = 0;
int i;
for_each_sgtable_dma_sg(sgt, sg, i) {
unsigned int len = sg_dma_len(sg);
if (!len)
break;
if (sg_dma_address(sg) != expected)
break;
expected += len;
size += len;
}
return size;
}
EXPORT_SYMBOL(drm_prime_get_contiguous_size);
/**
* drm_gem_prime_export - helper library implementation of the export callback
* @obj: GEM object to export
* @flags: flags like DRM_CLOEXEC and DRM_RDWR
*
* This is the implementation of the &drm_gem_object_funcs.export functions for GEM drivers
* using the PRIME helpers. It is used as the default in
* drm_gem_prime_handle_to_fd().
*/
struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
int flags)
{
struct drm_device *dev = obj->dev;
struct dma_buf_export_info exp_info = {
.exp_name = KBUILD_MODNAME, /* white lie for debug */
.owner = dev->driver->fops->owner,
.ops = &drm_gem_prime_dmabuf_ops,
.size = obj->size,
.flags = flags,
.priv = obj,
.resv = obj->resv,
};
return drm_gem_dmabuf_export(dev, &exp_info);
}
EXPORT_SYMBOL(drm_gem_prime_export);
/**
* drm_gem_prime_import_dev - core implementation of the import callback
* @dev: drm_device to import into
* @dma_buf: dma-buf object to import
* @attach_dev: struct device to dma_buf attach
*
* This is the core of drm_gem_prime_import(). It's designed to be called by
* drivers who want to use a different device structure than &drm_device.dev for
* attaching via dma_buf. This function calls
* &drm_driver.gem_prime_import_sg_table internally.
*
* Drivers must arrange to call drm_prime_gem_destroy() from their
* &drm_gem_object_funcs.free hook when using this function.
*/
struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
struct dma_buf *dma_buf,
struct device *attach_dev)
{
struct dma_buf_attachment *attach;
struct sg_table *sgt;
struct drm_gem_object *obj;
int ret;
if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
obj = dma_buf->priv;
if (obj->dev == dev) {
/*
* Importing dmabuf exported from our own gem increases
* refcount on gem itself instead of f_count of dmabuf.
*/
drm_gem_object_get(obj);
return obj;
}
}
if (!dev->driver->gem_prime_import_sg_table)
return ERR_PTR(-EINVAL);
attach = dma_buf_attach(dma_buf, attach_dev);
if (IS_ERR(attach))
return ERR_CAST(attach);
get_dma_buf(dma_buf);
sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto fail_detach;
}
obj = dev->driver->gem_prime_import_sg_table(dev, attach, sgt);
if (IS_ERR(obj)) {
ret = PTR_ERR(obj);
goto fail_unmap;
}
obj->import_attach = attach;
obj->resv = dma_buf->resv;
return obj;
fail_unmap:
dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
fail_detach:
dma_buf_detach(dma_buf, attach);
dma_buf_put(dma_buf);
return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_gem_prime_import_dev);
/**
* drm_gem_prime_import - helper library implementation of the import callback
* @dev: drm_device to import into
* @dma_buf: dma-buf object to import
*
* This is the implementation of the gem_prime_import functions for GEM drivers
* using the PRIME helpers. Drivers can use this as their
* &drm_driver.gem_prime_import implementation. It is used as the default
* implementation in drm_gem_prime_fd_to_handle().
*
* Drivers must arrange to call drm_prime_gem_destroy() from their
* &drm_gem_object_funcs.free hook when using this function.
*/
struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf)
{
return drm_gem_prime_import_dev(dev, dma_buf, dev->dev);
}
EXPORT_SYMBOL(drm_gem_prime_import);
/**
* drm_prime_sg_to_page_array - convert an sg table into a page array
* @sgt: scatter-gather table to convert
* @pages: array of page pointers to store the pages in
* @max_entries: size of the passed-in array
*
* Exports an sg table into an array of pages.
*
* This function is deprecated and strongly discouraged to be used.
* The page array is only useful for page faults and those can corrupt fields
* in the struct page if they are not handled by the exporting driver.
*/
int __deprecated drm_prime_sg_to_page_array(struct sg_table *sgt,
struct page **pages,
int max_entries)
{
struct sg_page_iter page_iter;
struct page **p = pages;
for_each_sgtable_page(sgt, &page_iter, 0) {
if (WARN_ON(p - pages >= max_entries))
return -1;
*p++ = sg_page_iter_page(&page_iter);
}
return 0;
}
EXPORT_SYMBOL(drm_prime_sg_to_page_array);
/**
* drm_prime_sg_to_dma_addr_array - convert an sg table into a dma addr array
* @sgt: scatter-gather table to convert
* @addrs: array to store the dma bus address of each page
* @max_entries: size of both the passed-in arrays
*
* Exports an sg table into an array of addresses.
*
* Drivers should use this in their &drm_driver.gem_prime_import_sg_table
* implementation.
*/
int drm_prime_sg_to_dma_addr_array(struct sg_table *sgt, dma_addr_t *addrs,
int max_entries)
{
struct sg_dma_page_iter dma_iter;
dma_addr_t *a = addrs;
for_each_sgtable_dma_page(sgt, &dma_iter, 0) {
if (WARN_ON(a - addrs >= max_entries))
return -1;
*a++ = sg_page_iter_dma_address(&dma_iter);
}
return 0;
}
EXPORT_SYMBOL(drm_prime_sg_to_dma_addr_array);
/**
* drm_prime_gem_destroy - helper to clean up a PRIME-imported GEM object
* @obj: GEM object which was created from a dma-buf
* @sg: the sg-table which was pinned at import time
*
* This is the cleanup functions which GEM drivers need to call when they use
* drm_gem_prime_import() or drm_gem_prime_import_dev() to import dma-bufs.
*/
void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *sg)
{
struct dma_buf_attachment *attach;
struct dma_buf *dma_buf;
attach = obj->import_attach;
if (sg)
dma_buf_unmap_attachment_unlocked(attach, sg, DMA_BIDIRECTIONAL);
dma_buf = attach->dmabuf;
dma_buf_detach(attach->dmabuf, attach);
/* remove the reference */
dma_buf_put(dma_buf);
}
EXPORT_SYMBOL(drm_prime_gem_destroy);
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