/* * 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 <airlied@redhat.com> * Rob Clark <rob.clark@linaro.org> * */ #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. */ static 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; } 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_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. */ static 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 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) { ret = -ENOENT; goto out_unlock; } dmabuf = drm_prime_lookup_buf_by_handle(&file_priv->prime, handle); if (dmabuf) { get_dma_buf(dmabuf); goto out_have_handle; } 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 */ ret = PTR_ERR(dmabuf); 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) goto fail_put_dmabuf; out_have_handle: ret = dma_buf_fd(dmabuf, flags); /* * We must _not_ remove the buffer from the handle cache since the newly * created dma buf is already linked in the global obj->dma_buf pointer, * and that is invariant as long as a userspace gem handle exists. * Closing the handle will clean out the cache anyway, so we don't leak. */ if (ret < 0) { goto fail_put_dmabuf; } else { *prime_fd = ret; ret = 0; } goto out; fail_put_dmabuf: dma_buf_put(dmabuf); out: drm_gem_object_put(obj); out_unlock: mutex_unlock(&file_priv->prime.lock); return ret; } 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; if (!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, 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 for * drivers that do not set their own. */ 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. It is the default for drivers that do * not set their own &drm_driver.gem_prime_import. * * 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