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 <christian.koenig@xxxxxxx>
---
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,
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