On Wed, Jul 17, 2019 at 02:15:37PM -0700, Rob Clark wrote: > From: Rob Clark <robdcl...@chromium.org> > > drm_cflush_pages() is no-op on arm/arm64. But instead we can use > dma_sync API. > > Fixes failures w/ vgem_test. > > Signed-off-by: Rob Clark <robdcl...@chromium.org> > --- > An alternative approach to the series[1] I sent yesterday > > On the plus side, it keeps the WC buffers and avoids any drm core > changes. On the minus side, I don't think it will work (at least > on arm64) prior to v5.0[2], so the fix can't be backported very > far.
Yeah seems a lot more reasonable. Acked-by: Daniel Vetter <daniel.vet...@ffwll.ch> > > [1] https://patchwork.freedesktop.org/series/63771/ > [2] depends on 356da6d0cde3323236977fce54c1f9612a742036 > > drivers/gpu/drm/vgem/vgem_drv.c | 130 ++++++++++++++++++++------------ > 1 file changed, 83 insertions(+), 47 deletions(-) > > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index 76d95b5e289c..6c9b5e20b3d4 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -47,10 +47,16 @@ static struct vgem_device { > struct platform_device *platform; > } *vgem_device; > > +static void sync_and_unpin(struct drm_vgem_gem_object *bo); > +static struct page **pin_and_sync(struct drm_vgem_gem_object *bo); > + > static void vgem_gem_free_object(struct drm_gem_object *obj) > { > struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj); > > + if (!obj->import_attach) > + sync_and_unpin(vgem_obj); > + > kvfree(vgem_obj->pages); > mutex_destroy(&vgem_obj->pages_lock); > > @@ -78,40 +84,15 @@ static vm_fault_t vgem_gem_fault(struct vm_fault *vmf) > return VM_FAULT_SIGBUS; > > mutex_lock(&obj->pages_lock); > + if (!obj->pages) > + pin_and_sync(obj); > if (obj->pages) { > get_page(obj->pages[page_offset]); > vmf->page = obj->pages[page_offset]; > ret = 0; > } > mutex_unlock(&obj->pages_lock); > - if (ret) { > - struct page *page; > - > - page = shmem_read_mapping_page( > - file_inode(obj->base.filp)->i_mapping, > - page_offset); > - if (!IS_ERR(page)) { > - vmf->page = page; > - ret = 0; > - } else switch (PTR_ERR(page)) { > - case -ENOSPC: > - case -ENOMEM: > - ret = VM_FAULT_OOM; > - break; > - case -EBUSY: > - ret = VM_FAULT_RETRY; > - break; > - case -EFAULT: > - case -EINVAL: > - ret = VM_FAULT_SIGBUS; > - break; > - default: > - WARN_ON(PTR_ERR(page)); > - ret = VM_FAULT_SIGBUS; > - break; > - } > > - } > return ret; > } > > @@ -277,32 +258,93 @@ static const struct file_operations vgem_driver_fops = { > .release = drm_release, > }; > > -static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo) > +/* Called under pages_lock, except in free path (where it can't race): */ > +static void sync_and_unpin(struct drm_vgem_gem_object *bo) > { > - mutex_lock(&bo->pages_lock); > - if (bo->pages_pin_count++ == 0) { > - struct page **pages; > + struct drm_device *dev = bo->base.dev; > + > + if (bo->table) { > + dma_sync_sg_for_cpu(dev->dev, bo->table->sgl, > + bo->table->nents, DMA_BIDIRECTIONAL); > + sg_free_table(bo->table); > + kfree(bo->table); > + bo->table = NULL; > + } > + > + if (bo->pages) { > + drm_gem_put_pages(&bo->base, bo->pages, true, true); > + bo->pages = NULL; > + } > +} > + > +static struct page **pin_and_sync(struct drm_vgem_gem_object *bo) > +{ > + struct drm_device *dev = bo->base.dev; > + int npages = bo->base.size >> PAGE_SHIFT; > + struct page **pages; > + struct sg_table *sgt; > + > + WARN_ON(!mutex_is_locked(&bo->pages_lock)); > + > + pages = drm_gem_get_pages(&bo->base); > + if (IS_ERR(pages)) { > + bo->pages_pin_count--; > + mutex_unlock(&bo->pages_lock); > + return pages; > + } > > - pages = drm_gem_get_pages(&bo->base); > - if (IS_ERR(pages)) { > - bo->pages_pin_count--; > - mutex_unlock(&bo->pages_lock); > - return pages; > - } > + sgt = drm_prime_pages_to_sg(pages, npages); > + if (IS_ERR(sgt)) { > + dev_err(dev->dev, > + "failed to allocate sgt: %ld\n", > + PTR_ERR(bo->table)); > + drm_gem_put_pages(&bo->base, pages, false, false); > + mutex_unlock(&bo->pages_lock); > + return ERR_CAST(bo->table); > + } > + > + /* > + * Flush the object from the CPU cache so that importers > + * can rely on coherent indirect access via the exported > + * dma-address. > + */ > + dma_sync_sg_for_device(dev->dev, sgt->sgl, > + sgt->nents, DMA_BIDIRECTIONAL); > + > + bo->pages = pages; > + bo->table = sgt; > + > + return pages; > +} > + > +static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo) > +{ > + struct page **pages; > > - bo->pages = pages; > + mutex_lock(&bo->pages_lock); > + if (bo->pages_pin_count++ == 0 && !bo->pages) { > + pages = pin_and_sync(bo); > + } else { > + WARN_ON(!bo->pages); > + pages = bo->pages; > } > mutex_unlock(&bo->pages_lock); > > - return bo->pages; > + return pages; > } > > static void vgem_unpin_pages(struct drm_vgem_gem_object *bo) > { > + /* > + * We shouldn't hit this for imported bo's.. in the import > + * case we don't own the scatter-table > + */ > + WARN_ON(bo->base.import_attach); > + > mutex_lock(&bo->pages_lock); > if (--bo->pages_pin_count == 0) { > - drm_gem_put_pages(&bo->base, bo->pages, true, true); > - bo->pages = NULL; > + WARN_ON(!bo->table); > + sync_and_unpin(bo); > } > mutex_unlock(&bo->pages_lock); > } > @@ -310,18 +352,12 @@ static void vgem_unpin_pages(struct drm_vgem_gem_object > *bo) > static int vgem_prime_pin(struct drm_gem_object *obj) > { > struct drm_vgem_gem_object *bo = to_vgem_bo(obj); > - long n_pages = obj->size >> PAGE_SHIFT; > struct page **pages; > > pages = vgem_pin_pages(bo); > if (IS_ERR(pages)) > return PTR_ERR(pages); > > - /* Flush the object from the CPU cache so that importers can rely > - * on coherent indirect access via the exported dma-address. > - */ > - drm_clflush_pages(pages, n_pages); > - > return 0; > } > > -- > 2.21.0 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
