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RCPT_COUNT_SEVEN(0.00)[11]; RCVD_VIA_SMTP_AUTH(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DKIM_TRACE(0.00)[suse.de:+]; ASN(0.00)[asn:25478, ipnet:::/0, country:RU]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Score: -4.51 X-Spam-Flag: NO (cc'ing Christian) Hi, I don't feel qualified to fully review this patch. It would be good to have the issue with sg-tables solved, but I dislike the dedicated initializer macros. So my question is if this has any drawbacks. Or could we make this available and the default for all shmem-based drivers? Best regards Thomas Am 01.05.25 um 08:43 schrieb oushixiong1025@163.com: > From: Shixiong Ou > > [WHY] > 1. Drivers using DRM_GEM_SHADOW_PLANE_HELPER_FUNCS and > DRM_GEM_SHMEM_DRIVER_OPS (e.g., udl, ast) do not require > sg_table import. > They only need dma_buf_vmap() to access the shared buffer's > kernel virtual address. > > 2. On certain Aspeed-based boards, a dma_mask of 0xffff_ffff may > trigger SWIOTLB during dmabuf import. However, IO_TLB_SEGSIZE > restricts the maximum DMA streaming mapping memory, resulting in > errors like: > > ast 0000:07:00.0: swiotlb buffer is full (sz: 3145728 bytes), total 32768 (slots), used 0 (slots) > > [HOW] > Provide a gem_prime_import implementation without sg_table mapping > to avoid issues (e.g., "swiotlb buffer is full"). Drivers that do not > require sg_table can adopt this. > > Signed-off-by: Shixiong Ou > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 95 ++++++++++++++++++++++++++ > include/drm/drm_gem_shmem_helper.h | 24 +++++++ > 2 files changed, 119 insertions(+) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index d99dee67353a..9e41e350ff6f 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -39,6 +39,7 @@ MODULE_IMPORT_NS("DMA_BUF"); > static const struct drm_gem_object_funcs drm_gem_shmem_funcs = { > .free = drm_gem_shmem_object_free, > .print_info = drm_gem_shmem_object_print_info, > + .export = drm_gem_shmem_object_prime_export, > .pin = drm_gem_shmem_object_pin, > .unpin = drm_gem_shmem_object_unpin, > .get_sg_table = drm_gem_shmem_object_get_sg_table, > @@ -799,6 +800,100 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device *dev, > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table); > > +const struct dma_buf_ops drm_gem_shmem_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_gem_shmem_prime_export - implementation of the export callback > + * @shmem: shmem GEM object > + */ > +struct dma_buf *drm_gem_shmem_prime_export(struct drm_gem_shmem_object *shmem, > + int flags) > +{ > + struct drm_gem_object *obj = &shmem->base; > + 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_shmem_prime_dmabuf_ops, > + .size = obj->size, > + .flags = flags, > + .priv = obj, > + .resv = obj->resv, > + }; > + > + return drm_gem_dmabuf_export(dev, &exp_info); > +} > + > +/** > + * drm_gem_shmem_prime_import - Import dmabuf without mapping its sg_table > + * @dev: Device to import into > + * @dma_buf: dma-buf object to import > + * > + * Drivers that use the shmem helpers but also wants to import dmabuf without > + * mapping its sg_table can use this as their &drm_driver.gem_prime_import > + * implementation. > + */ > +struct drm_gem_object *drm_gem_shmem_prime_import(struct drm_device *dev, > + struct dma_buf *dma_buf) > +{ > + struct dma_buf_attachment *attach; > + struct drm_gem_shmem_object *shmem; > + size_t size; > + int ret; > + > + if (dma_buf->ops == &drm_gem_shmem_prime_dmabuf_ops) { > + struct drm_gem_object *obj; > + > + 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; > + } > + } > + > + attach = dma_buf_attach(dma_buf, dev->dev); > + if (IS_ERR(attach)) > + return ERR_CAST(attach); > + > + get_dma_buf(dma_buf); > + > + size = PAGE_ALIGN(attach->dmabuf->size); > + > + shmem = __drm_gem_shmem_create(dev, size, true, NULL); > + if (IS_ERR(shmem)) { > + ret = PTR_ERR(shmem); > + goto fail_detach; > + } > + > + drm_dbg_prime(dev, "size = %zu\n", size); > + > + shmem->base.import_attach = attach; > + shmem->base.resv = dma_buf->resv; > + > + return &shmem->base; > + > +fail_detach: > + dma_buf_detach(dma_buf, attach); > + dma_buf_put(dma_buf); > + > + return ERR_PTR(ret); > +} > +EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import); > + > MODULE_DESCRIPTION("DRM SHMEM memory-management helpers"); > MODULE_IMPORT_NS("DMA_BUF"); > MODULE_LICENSE("GPL v2"); > diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h > index cef5a6b5a4d6..78ef91593a8e 100644 > --- a/include/drm/drm_gem_shmem_helper.h > +++ b/include/drm/drm_gem_shmem_helper.h > @@ -110,6 +110,8 @@ int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, > void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, > struct iosys_map *map); > int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma); > +struct dma_buf *drm_gem_shmem_prime_export(struct drm_gem_shmem_object *shmem, > + int flags); > > int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem); > void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem); > @@ -168,6 +170,18 @@ static inline void drm_gem_shmem_object_print_info(struct drm_printer *p, unsign > drm_gem_shmem_print_info(shmem, p, indent); > } > > +/** > + * drm_gem_shmem_object_prime_export - GEM object function for export() > + * @obj: GEM object > + * > + */ > +static inline struct dma_buf *drm_gem_shmem_object_prime_export(struct drm_gem_object *obj, > + int flags) > +{ > + struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); > + > + return drm_gem_shmem_prime_export(shmem, flags); > +} > /** > * drm_gem_shmem_object_pin - GEM object function for drm_gem_shmem_pin() > * @obj: GEM object > @@ -276,6 +290,8 @@ drm_gem_shmem_prime_import_sg_table(struct drm_device *dev, > struct sg_table *sgt); > int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, > struct drm_mode_create_dumb *args); > +struct drm_gem_object *drm_gem_shmem_prime_import(struct drm_device *dev, > + struct dma_buf *buf); > > /** > * DRM_GEM_SHMEM_DRIVER_OPS - Default shmem GEM operations > @@ -287,4 +303,12 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev, > .gem_prime_import_sg_table = drm_gem_shmem_prime_import_sg_table, \ > .dumb_create = drm_gem_shmem_dumb_create > > +/** > + * This macro provides a shmem GEM operations that implementate a simple > + * gem_prime_import. > + */ > +#define DRM_GEM_SHMEM_SIMPLE_DRIVER_OPS \ > + .gem_prime_import = drm_gem_shmem_prime_import, \ > + .dumb_create = drm_gem_shmem_dumb_create > + > #endif /* __DRM_GEM_SHMEM_HELPER_H__ */ -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)