From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bn3nam01on0052.outbound.protection.outlook.com ([104.47.33.52]:14659 "EHLO NAM01-BN3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965101AbeF1J6R (ORCPT ); Thu, 28 Jun 2018 05:58:17 -0400 Message-ID: <5B34B132.3060504@amd.com> Date: Thu, 28 Jun 2018 17:58:10 +0800 From: "Zhang, Jerry (Junwei)" MIME-Version: 1.0 To: =?UTF-8?B?Q2hyaXN0aWFuIEvDtm5pZw==?= , , , , , , Subject: Re: [PATCH 3/4] drm/amdgpu: add independent DMA-buf export v3 References: <20180622141103.1787-1-christian.koenig@amd.com> <20180622141103.1787-4-christian.koenig@amd.com> In-Reply-To: <20180622141103.1787-4-christian.koenig@amd.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On 06/22/2018 10:11 PM, Christian König wrote: > The caching of SGT's done by the DRM code is actually quite harmful and > should probably removed altogether in the long term. > > Start by providing a separate DMA-buf export implementation in amdgpu. This is > also a prerequisite of unpinned DMA-buf handling. > > v2: fix unintended recursion, remove debugging leftovers > v3: split out from unpinned DMA-buf work > > Signed-off-by: Christian König > --- > drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 - > drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 1 - > drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 94 +++++++++++++------------------ > 3 files changed, 39 insertions(+), 57 deletions(-) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > index d8e0cc08f9db..5e71af8dd3a7 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h > @@ -373,7 +373,6 @@ int amdgpu_gem_object_open(struct drm_gem_object *obj, > void amdgpu_gem_object_close(struct drm_gem_object *obj, > struct drm_file *file_priv); > unsigned long amdgpu_gem_timeout(uint64_t timeout_ns); > -struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj); > struct drm_gem_object * > amdgpu_gem_prime_import_sg_table(struct drm_device *dev, > struct dma_buf_attachment *attach, > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > index a549483032b0..cdf0be85d361 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c > @@ -919,7 +919,6 @@ static struct drm_driver kms_driver = { > .gem_prime_export = amdgpu_gem_prime_export, > .gem_prime_import = amdgpu_gem_prime_import, > .gem_prime_res_obj = amdgpu_gem_prime_res_obj, > - .gem_prime_get_sg_table = amdgpu_gem_prime_get_sg_table, I may miss some patches or important info. Even applied the series of patch, I still could find below code in drm_gem_map_dma_buf(). In this case, it will cause NULL pointer access. Please help me out of here. {{{ sgt = obj->dev->driver->gem_prime_get_sg_table(obj); }}} Jerry > .gem_prime_import_sg_table = amdgpu_gem_prime_import_sg_table, > .gem_prime_vmap = amdgpu_gem_prime_vmap, > .gem_prime_vunmap = amdgpu_gem_prime_vunmap, > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c > index b2286bc41aec..038a8c8488b7 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c > @@ -40,22 +40,6 @@ > > static const struct dma_buf_ops amdgpu_dmabuf_ops; > > -/** > - * amdgpu_gem_prime_get_sg_table - &drm_driver.gem_prime_get_sg_table > - * implementation > - * @obj: GEM buffer object > - * > - * Returns: > - * A scatter/gather table for the pinned pages of the buffer object's memory. > - */ > -struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj) > -{ > - struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj); > - int npages = bo->tbo.num_pages; > - > - return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages); > -} > - > /** > * amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation > * @obj: GEM buffer object > @@ -189,35 +173,29 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev, > } > > /** > - * amdgpu_gem_map_attach - &dma_buf_ops.attach implementation > - * @dma_buf: shared DMA buffer > - * @target_dev: target device > + * amdgpu_gem_map_dma_buf - &dma_buf_ops.map_dma_buf implementation > * @attach: DMA-buf attachment > + * @dir: DMA direction > * > * Makes sure that the shared DMA buffer can be accessed by the target device. > * For now, simply pins it to the GTT domain, where it should be accessible by > * all DMA devices. > * > * Returns: > - * 0 on success or negative error code. > + * sg_table filled with the DMA addresses to use or ERR_PRT with negative error > + * code. > */ > -static int amdgpu_gem_map_attach(struct dma_buf *dma_buf, > - struct dma_buf_attachment *attach) > +static struct sg_table * > +amdgpu_gem_map_dma_buf(struct dma_buf_attachment *attach, > + enum dma_data_direction dir) > { > + struct dma_buf *dma_buf = attach->dmabuf; > struct drm_gem_object *obj = dma_buf->priv; > struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj); > struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev); > + struct sg_table *sgt; > long r; > > - r = drm_gem_map_attach(dma_buf, attach); > - if (r) > - return r; > - > - r = amdgpu_bo_reserve(bo, false); > - if (unlikely(r != 0)) > - goto error_detach; > - > - > if (attach->dev->driver != adev->dev->driver) { > /* > * Wait for all shared fences to complete before we switch to future > @@ -228,54 +206,62 @@ static int amdgpu_gem_map_attach(struct dma_buf *dma_buf, > MAX_SCHEDULE_TIMEOUT); > if (unlikely(r < 0)) { > DRM_DEBUG_PRIME("Fence wait failed: %li\n", r); > - goto error_unreserve; > + return ERR_PTR(r); > } > } > > /* pin buffer into GTT */ > r = amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT, NULL); > if (r) > - goto error_unreserve; > + return ERR_PTR(r); > + > + sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages, bo->tbo.num_pages); > + if (IS_ERR(sgt)) > + return sgt; > + > + if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, > + DMA_ATTR_SKIP_CPU_SYNC)) > + goto error_free; > > if (attach->dev->driver != adev->dev->driver) > bo->prime_shared_count++; > > -error_unreserve: > - amdgpu_bo_unreserve(bo); > + return sgt; > > -error_detach: > - if (r) > - drm_gem_map_detach(dma_buf, attach); > - return r; > +error_free: > + sg_free_table(sgt); > + kfree(sgt); > + return ERR_PTR(-ENOMEM); > } > > /** > - * amdgpu_gem_map_detach - &dma_buf_ops.detach implementation > - * @dma_buf: shared DMA buffer > + * amdgpu_gem_unmap_dma_buf - &dma_buf_ops.unmap_dma_buf implementation > * @attach: DMA-buf attachment > + * @sgt: sg_table to unmap > + * @dir: DMA direction > * > * This is called when a shared DMA buffer no longer needs to be accessible by > * the other device. For now, simply unpins the buffer from GTT. > */ > -static void amdgpu_gem_map_detach(struct dma_buf *dma_buf, > - struct dma_buf_attachment *attach) > +static void amdgpu_gem_unmap_dma_buf(struct dma_buf_attachment *attach, > + struct sg_table *sgt, > + enum dma_data_direction dir) > { > + struct dma_buf *dma_buf = attach->dmabuf; > struct drm_gem_object *obj = dma_buf->priv; > struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj); > struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev); > - int ret = 0; > - > - ret = amdgpu_bo_reserve(bo, true); > - if (unlikely(ret != 0)) > - goto error; > > amdgpu_bo_unpin(bo); > + > if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count) > bo->prime_shared_count--; > - amdgpu_bo_unreserve(bo); > > -error: > - drm_gem_map_detach(dma_buf, attach); > + if (sgt) { > + dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir); > + sg_free_table(sgt); > + kfree(sgt); > + } > } > > /** > @@ -333,10 +319,8 @@ static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf, > } > > static const struct dma_buf_ops amdgpu_dmabuf_ops = { > - .attach = amdgpu_gem_map_attach, > - .detach = amdgpu_gem_map_detach, > - .map_dma_buf = drm_gem_map_dma_buf, > - .unmap_dma_buf = drm_gem_unmap_dma_buf, > + .map_dma_buf = amdgpu_gem_map_dma_buf, > + .unmap_dma_buf = amdgpu_gem_unmap_dma_buf, > .release = drm_gem_dmabuf_release, > .begin_cpu_access = amdgpu_gem_begin_cpu_access, > .map = drm_gem_dmabuf_kmap, >