[PATCH 01/15] dma-resv: Fix kerneldoc

[PATCH 01/15] dma-resv: Fix kerneldoc

[Daniel Vetter]

Oversight from

commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9
Author: Christian König <christian.koenig@amd.com>
Date:   Mon May 10 16:14:09 2021 +0200

    dma-buf: rename and cleanup dma_resv_get_excl v3

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
---
 include/linux/dma-resv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 562b885cf9c3..e1ca2080a1ff 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
 }
 
 /**
- * dma_resv_exclusive - return the object's exclusive fence
+ * dma_resv_excl_fence - return the object's exclusive fence
  * @obj: the reservation object
  *
  * Returns the exclusive fence (if any). Caller must either hold the objects
-- 
2.32.0.rc2

[PATCH 02/15] dma-buf: Switch to inline kerneldoc

[Daniel Vetter]

Also review & update everything while we're at it.

This is prep work to smash a ton of stuff into the kerneldoc for
@resv.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Nirmoy Das <nirmoy.das@amd.com>
Cc: Deepak R Varma <mh12gx2825@gmail.com>
Cc: Chen Li <chenli@uniontech.com>
Cc: Kevin Wang <kevin1.wang@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
---
 include/linux/dma-buf.h | 107 +++++++++++++++++++++++++++++++---------
 1 file changed, 83 insertions(+), 24 deletions(-)

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 92eec38a03aa..6d18b9e448b9 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -289,28 +289,6 @@ struct dma_buf_ops {
 
 /**
  * struct dma_buf - shared buffer object
- * @size: size of the buffer; invariant over the lifetime of the buffer.
- * @file: file pointer used for sharing buffers across, and for refcounting.
- * @attachments: list of dma_buf_attachment that denotes all devices attached,
- *               protected by dma_resv lock.
- * @ops: dma_buf_ops associated with this buffer object.
- * @lock: used internally to serialize list manipulation, attach/detach and
- *        vmap/unmap
- * @vmapping_counter: used internally to refcnt the vmaps
- * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
- * @exp_name: name of the exporter; useful for debugging.
- * @name: userspace-provided name; useful for accounting and debugging,
- *        protected by @resv.
- * @name_lock: spinlock to protect name access
- * @owner: pointer to exporter module; used for refcounting when exporter is a
- *         kernel module.
- * @list_node: node for dma_buf accounting and debugging.
- * @priv: exporter specific private data for this buffer object.
- * @resv: reservation object linked to this dma-buf
- * @poll: for userspace poll support
- * @cb_excl: for userspace poll support
- * @cb_shared: for userspace poll support
- * @sysfs_entry: for exposing information about this buffer in sysfs.
  * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
  * and is incremented on each attach.
  *
@@ -324,24 +302,100 @@ struct dma_buf_ops {
  * Device DMA access is handled by the separate &struct dma_buf_attachment.
  */
 struct dma_buf {
+	/**
+	 * @size:
+	 *
+	 * Size of the buffer; invariant over the lifetime of the buffer.
+	 */
 	size_t size;
+
+	/**
+	 * @file:
+	 *
+	 * File pointer used for sharing buffers across, and for refcounting.
+	 * See dma_buf_get() and dma_buf_put().
+	 */
 	struct file *file;
+
+	/**
+	 * @attachments:
+	 *
+	 * List of dma_buf_attachment that denotes all devices attached,
+	 * protected by &dma_resv lock @resv.
+	 */
 	struct list_head attachments;
+
+	/** @ops: dma_buf_ops associated with this buffer object. */
 	const struct dma_buf_ops *ops;
+
+	/**
+	 * @lock:
+	 *
+	 * Used internally to serialize list manipulation, attach/detach and
+	 * vmap/unmap. Note that in many cases this is superseeded by
+	 * dma_resv_lock() on @resv.
+	 */
 	struct mutex lock;
+
+	/**
+	 * @vmapping_counter:
+	 *
+	 * Used internally to refcnt the vmaps returned by dma_buf_vmap().
+	 * Protected by @lock.
+	 */
 	unsigned vmapping_counter;
+
+	/**
+	 * @vmap_ptr:
+	 * The current vmap ptr if @vmapping_counter > 0. Protected by @lock.
+	 */
 	struct dma_buf_map vmap_ptr;
+
+	/**
+	 * @exp_name:
+	 *
+	 * Name of the exporter; useful for debugging. See the
+	 * DMA_BUF_SET_NAME IOCTL.
+	 */
 	const char *exp_name;
+
+	/**
+	 * @name:
+	 *
+	 * Userspace-provided name; useful for accounting and debugging,
+	 * protected by dma_resv_lock() on @resv and @name_lock for read access.
+	 */
 	const char *name;
+
+	/** @name_lock: Spinlock to protect name acces for read access. */
 	spinlock_t name_lock;
+
+	/**
+	 * @owner:
+	 *
+	 * Pointer to exporter module; used for refcounting when exporter is a
+	 * kernel module.
+	 */
 	struct module *owner;
+
+	/** @list_node: node for dma_buf accounting and debugging. */
 	struct list_head list_node;
+
+	/** @priv: exporter specific private data for this buffer object. */
 	void *priv;
+
+	/**
+	 * @resv:
+	 *
+	 * Reservation object linked to this dma-buf.
+	 */
 	struct dma_resv *resv;
 
-	/* poll support */
+	/** @poll: for userspace poll support */
 	wait_queue_head_t poll;
 
+	/** @cb_excl: for userspace poll support */
+	/** @cb_shared: for userspace poll support */
 	struct dma_buf_poll_cb_t {
 		struct dma_fence_cb cb;
 		wait_queue_head_t *poll;
@@ -349,7 +403,12 @@ struct dma_buf {
 		__poll_t active;
 	} cb_excl, cb_shared;
 #ifdef CONFIG_DMABUF_SYSFS_STATS
-	/* for sysfs stats */
+	/**
+	 * @sysfs_entry:
+	 *
+	 * For exposing information about this buffer in sysfs. See also
+	 * `DMA-BUF statistics`_ for the uapi this enables.
+	 */
 	struct dma_buf_sysfs_entry {
 		struct kobject kobj;
 		struct dma_buf *dmabuf;
-- 
2.32.0.rc2

[PATCH 05/15] drm/panfrost: Use xarray and helpers for depedency tracking

[Daniel Vetter]

More consistency and prep work for the next patch.

Aside: I wonder whether we shouldn't just move this entire xarray
business into the scheduler so that not everyone has to reinvent the
same wheels. Cc'ing some scheduler people for this too.

v2: Correctly handle sched_lock since Lucas pointed out it's needed.

v3: Rebase, dma_resv_get_excl_unlocked got renamed

v4: Don't leak job references on failure (Steven).

Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Luben Tuikov <luben.tuikov@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/panfrost/panfrost_drv.c | 41 +++++++---------
 drivers/gpu/drm/panfrost/panfrost_job.c | 65 +++++++++++--------------
 drivers/gpu/drm/panfrost/panfrost_job.h |  8 ++-
 3 files changed, 49 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 075ec0ef746c..3ee828f1e7a5 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -138,12 +138,6 @@ panfrost_lookup_bos(struct drm_device *dev,
 	if (!job->bo_count)
 		return 0;
 
-	job->implicit_fences = kvmalloc_array(job->bo_count,
-				  sizeof(struct dma_fence *),
-				  GFP_KERNEL | __GFP_ZERO);
-	if (!job->implicit_fences)
-		return -ENOMEM;
-
 	ret = drm_gem_objects_lookup(file_priv,
 				     (void __user *)(uintptr_t)args->bo_handles,
 				     job->bo_count, &job->bos);
@@ -174,7 +168,7 @@ panfrost_lookup_bos(struct drm_device *dev,
 }
 
 /**
- * panfrost_copy_in_sync() - Sets up job->in_fences[] with the sync objects
+ * panfrost_copy_in_sync() - Sets up job->deps with the sync objects
  * referenced by the job.
  * @dev: DRM device
  * @file_priv: DRM file for this fd
@@ -194,22 +188,14 @@ panfrost_copy_in_sync(struct drm_device *dev,
 {
 	u32 *handles;
 	int ret = 0;
-	int i;
+	int i, in_fence_count;
 
-	job->in_fence_count = args->in_sync_count;
+	in_fence_count = args->in_sync_count;
 
-	if (!job->in_fence_count)
+	if (!in_fence_count)
 		return 0;
 
-	job->in_fences = kvmalloc_array(job->in_fence_count,
-					sizeof(struct dma_fence *),
-					GFP_KERNEL | __GFP_ZERO);
-	if (!job->in_fences) {
-		DRM_DEBUG("Failed to allocate job in fences\n");
-		return -ENOMEM;
-	}
-
-	handles = kvmalloc_array(job->in_fence_count, sizeof(u32), GFP_KERNEL);
+	handles = kvmalloc_array(in_fence_count, sizeof(u32), GFP_KERNEL);
 	if (!handles) {
 		ret = -ENOMEM;
 		DRM_DEBUG("Failed to allocate incoming syncobj handles\n");
@@ -218,16 +204,23 @@ panfrost_copy_in_sync(struct drm_device *dev,
 
 	if (copy_from_user(handles,
 			   (void __user *)(uintptr_t)args->in_syncs,
-			   job->in_fence_count * sizeof(u32))) {
+			   in_fence_count * sizeof(u32))) {
 		ret = -EFAULT;
 		DRM_DEBUG("Failed to copy in syncobj handles\n");
 		goto fail;
 	}
 
-	for (i = 0; i < job->in_fence_count; i++) {
+	for (i = 0; i < in_fence_count; i++) {
+		struct dma_fence *fence;
+
 		ret = drm_syncobj_find_fence(file_priv, handles[i], 0, 0,
-					     &job->in_fences[i]);
-		if (ret == -EINVAL)
+					     &fence);
+		if (ret)
+			goto fail;
+
+		ret = drm_gem_fence_array_add(&job->deps, fence);
+
+		if (ret)
 			goto fail;
 	}
 
@@ -265,6 +258,8 @@ static int panfrost_ioctl_submit(struct drm_device *dev, void *data,
 
 	kref_init(&job->refcount);
 
+	xa_init_flags(&job->deps, XA_FLAGS_ALLOC);
+
 	job->pfdev = pfdev;
 	job->jc = args->jc;
 	job->requirements = args->requirements;
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 38f8580c19f1..71cd43fa1b36 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -196,14 +196,21 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
 	job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
 }
 
-static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
-					   int bo_count,
-					   struct dma_fence **implicit_fences)
+static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
+					  int bo_count,
+					  struct xarray *deps)
 {
-	int i;
+	int i, ret;
 
-	for (i = 0; i < bo_count; i++)
-		implicit_fences[i] = dma_resv_get_excl_unlocked(bos[i]->resv);
+	for (i = 0; i < bo_count; i++) {
+		struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
+
+		ret = drm_gem_fence_array_add(deps, fence);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
 }
 
 static void panfrost_attach_object_fences(struct drm_gem_object **bos,
@@ -240,10 +247,14 @@ int panfrost_job_push(struct panfrost_job *job)
 
 	job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
 
-	kref_get(&job->refcount); /* put by scheduler job completion */
+	ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
+					     &job->deps);
+	if (ret) {
+		mutex_unlock(&pfdev->sched_lock);
+		goto unlock;
+	}
 
-	panfrost_acquire_object_fences(job->bos, job->bo_count,
-				       job->implicit_fences);
+	kref_get(&job->refcount); /* put by scheduler job completion */
 
 	drm_sched_entity_push_job(&job->base, entity);
 
@@ -262,18 +273,15 @@ static void panfrost_job_cleanup(struct kref *ref)
 {
 	struct panfrost_job *job = container_of(ref, struct panfrost_job,
 						refcount);
+	struct dma_fence *fence;
+	unsigned long index;
 	unsigned int i;
 
-	if (job->in_fences) {
-		for (i = 0; i < job->in_fence_count; i++)
-			dma_fence_put(job->in_fences[i]);
-		kvfree(job->in_fences);
-	}
-	if (job->implicit_fences) {
-		for (i = 0; i < job->bo_count; i++)
-			dma_fence_put(job->implicit_fences[i]);
-		kvfree(job->implicit_fences);
+	xa_for_each(&job->deps, index, fence) {
+		dma_fence_put(fence);
 	}
+	xa_destroy(&job->deps);
+
 	dma_fence_put(job->done_fence);
 	dma_fence_put(job->render_done_fence);
 
@@ -316,26 +324,9 @@ static struct dma_fence *panfrost_job_dependency(struct drm_sched_job *sched_job
 						 struct drm_sched_entity *s_entity)
 {
 	struct panfrost_job *job = to_panfrost_job(sched_job);
-	struct dma_fence *fence;
-	unsigned int i;
-
-	/* Explicit fences */
-	for (i = 0; i < job->in_fence_count; i++) {
-		if (job->in_fences[i]) {
-			fence = job->in_fences[i];
-			job->in_fences[i] = NULL;
-			return fence;
-		}
-	}
 
-	/* Implicit fences, max. one per BO */
-	for (i = 0; i < job->bo_count; i++) {
-		if (job->implicit_fences[i]) {
-			fence = job->implicit_fences[i];
-			job->implicit_fences[i] = NULL;
-			return fence;
-		}
-	}
+	if (!xa_empty(&job->deps))
+		return xa_erase(&job->deps, job->last_dep++);
 
 	return NULL;
 }
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
index bbd3ba97ff67..82306a03b57e 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.h
+++ b/drivers/gpu/drm/panfrost/panfrost_job.h
@@ -19,9 +19,9 @@ struct panfrost_job {
 	struct panfrost_device *pfdev;
 	struct panfrost_file_priv *file_priv;
 
-	/* Optional fences userspace can pass in for the job to depend on. */
-	struct dma_fence **in_fences;
-	u32 in_fence_count;
+	/* Contains both explicit and implicit fences */
+	struct xarray deps;
+	unsigned long last_dep;
 
 	/* Fence to be signaled by IRQ handler when the job is complete. */
 	struct dma_fence *done_fence;
@@ -30,8 +30,6 @@ struct panfrost_job {
 	__u32 requirements;
 	__u32 flush_id;
 
-	/* Exclusive fences we have taken from the BOs to wait for */
-	struct dma_fence **implicit_fences;
 	struct panfrost_gem_mapping **mappings;
 	struct drm_gem_object **bos;
 	u32 bo_count;
-- 
2.32.0.rc2

[PATCH 06/15] drm/panfrost: Fix implicit sync

[Daniel Vetter]

Currently this has no practial relevance I think because there's not
many who can pull off a setup with panfrost and another gpu in the
same system. But the rules are that if you're setting an exclusive
fence, indicating a gpu write access in the implicit fencing system,
then you need to wait for all fences, not just the previous exclusive
fence.

panfrost against itself has no problem, because it always sets the
exclusive fence (but that's probably something that will need to be
fixed for vulkan and/or multi-engine gpus, or you'll suffer badly).
Also no problem with that against display.

With the prep work done to switch over to the dependency helpers this
is now a oneliner.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
---
 drivers/gpu/drm/panfrost/panfrost_job.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 71cd43fa1b36..ef004d587dc4 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -203,9 +203,8 @@ static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
 	int i, ret;
 
 	for (i = 0; i < bo_count; i++) {
-		struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
-
-		ret = drm_gem_fence_array_add(deps, fence);
+		/* panfrost always uses write mode in its current uapi */
+		ret = drm_gem_fence_array_add_implicit(deps, bos[i], true);
 		if (ret)
 			return ret;
 	}
-- 
2.32.0.rc2

Re: [PATCH 01/15] dma-resv: Fix kerneldoc

[Alex Deucher]

On Tue, Jun 22, 2021 at 12:55 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> Oversight from
>
> commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9
> Author: Christian König <christian.koenig@amd.com>
> Date:   Mon May 10 16:14:09 2021 +0200
>
>     dma-buf: rename and cleanup dma_resv_get_excl v3
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

> ---
>  include/linux/dma-resv.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
> index 562b885cf9c3..e1ca2080a1ff 100644
> --- a/include/linux/dma-resv.h
> +++ b/include/linux/dma-resv.h
> @@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
>  }
>
>  /**
> - * dma_resv_exclusive - return the object's exclusive fence
> + * dma_resv_excl_fence - return the object's exclusive fence
>   * @obj: the reservation object
>   *
>   * Returns the exclusive fence (if any). Caller must either hold the objects
> --
> 2.32.0.rc2
>

Re: [PATCH 02/15] dma-buf: Switch to inline kerneldoc

[Alex Deucher]

On Tue, Jun 22, 2021 at 12:55 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> Also review & update everything while we're at it.
>
> This is prep work to smash a ton of stuff into the kerneldoc for
> @resv.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Nirmoy Das <nirmoy.das@amd.com>
> Cc: Deepak R Varma <mh12gx2825@gmail.com>
> Cc: Chen Li <chenli@uniontech.com>
> Cc: Kevin Wang <kevin1.wang@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> ---
>  include/linux/dma-buf.h | 107 +++++++++++++++++++++++++++++++---------
>  1 file changed, 83 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 92eec38a03aa..6d18b9e448b9 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -289,28 +289,6 @@ struct dma_buf_ops {
>
>  /**
>   * struct dma_buf - shared buffer object
> - * @size: size of the buffer; invariant over the lifetime of the buffer.
> - * @file: file pointer used for sharing buffers across, and for refcounting.
> - * @attachments: list of dma_buf_attachment that denotes all devices attached,
> - *               protected by dma_resv lock.
> - * @ops: dma_buf_ops associated with this buffer object.
> - * @lock: used internally to serialize list manipulation, attach/detach and
> - *        vmap/unmap
> - * @vmapping_counter: used internally to refcnt the vmaps
> - * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
> - * @exp_name: name of the exporter; useful for debugging.
> - * @name: userspace-provided name; useful for accounting and debugging,
> - *        protected by @resv.
> - * @name_lock: spinlock to protect name access
> - * @owner: pointer to exporter module; used for refcounting when exporter is a
> - *         kernel module.
> - * @list_node: node for dma_buf accounting and debugging.
> - * @priv: exporter specific private data for this buffer object.
> - * @resv: reservation object linked to this dma-buf
> - * @poll: for userspace poll support
> - * @cb_excl: for userspace poll support
> - * @cb_shared: for userspace poll support
> - * @sysfs_entry: for exposing information about this buffer in sysfs.
>   * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
>   * and is incremented on each attach.
>   *
> @@ -324,24 +302,100 @@ struct dma_buf_ops {
>   * Device DMA access is handled by the separate &struct dma_buf_attachment.
>   */
>  struct dma_buf {
> +       /**
> +        * @size:
> +        *
> +        * Size of the buffer; invariant over the lifetime of the buffer.
> +        */
>         size_t size;
> +
> +       /**
> +        * @file:
> +        *
> +        * File pointer used for sharing buffers across, and for refcounting.
> +        * See dma_buf_get() and dma_buf_put().
> +        */
>         struct file *file;
> +
> +       /**
> +        * @attachments:
> +        *
> +        * List of dma_buf_attachment that denotes all devices attached,
> +        * protected by &dma_resv lock @resv.
> +        */
>         struct list_head attachments;
> +
> +       /** @ops: dma_buf_ops associated with this buffer object. */

For consistency you may want to format this like:
/**
  * @ops:
  *
  * dma_buf_ops associated with this buffer object.
  */

>         const struct dma_buf_ops *ops;
> +
> +       /**
> +        * @lock:
> +        *
> +        * Used internally to serialize list manipulation, attach/detach and
> +        * vmap/unmap. Note that in many cases this is superseeded by
> +        * dma_resv_lock() on @resv.
> +        */
>         struct mutex lock;
> +
> +       /**
> +        * @vmapping_counter:
> +        *
> +        * Used internally to refcnt the vmaps returned by dma_buf_vmap().
> +        * Protected by @lock.
> +        */
>         unsigned vmapping_counter;
> +
> +       /**
> +        * @vmap_ptr:
> +        * The current vmap ptr if @vmapping_counter > 0. Protected by @lock.
> +        */

Same comment as above.

>         struct dma_buf_map vmap_ptr;
> +
> +       /**
> +        * @exp_name:
> +        *
> +        * Name of the exporter; useful for debugging. See the
> +        * DMA_BUF_SET_NAME IOCTL.
> +        */
>         const char *exp_name;
> +
> +       /**
> +        * @name:
> +        *
> +        * Userspace-provided name; useful for accounting and debugging,
> +        * protected by dma_resv_lock() on @resv and @name_lock for read access.
> +        */
>         const char *name;
> +
> +       /** @name_lock: Spinlock to protect name acces for read access. */
>         spinlock_t name_lock;
> +
> +       /**
> +        * @owner:
> +        *
> +        * Pointer to exporter module; used for refcounting when exporter is a
> +        * kernel module.
> +        */
>         struct module *owner;
> +
> +       /** @list_node: node for dma_buf accounting and debugging. */

and here.

>         struct list_head list_node;
> +
> +       /** @priv: exporter specific private data for this buffer object. */

and here.

>         void *priv;
> +
> +       /**
> +        * @resv:
> +        *
> +        * Reservation object linked to this dma-buf.
> +        */
>         struct dma_resv *resv;
>
> -       /* poll support */
> +       /** @poll: for userspace poll support */

here.

>         wait_queue_head_t poll;
>
> +       /** @cb_excl: for userspace poll support */
> +       /** @cb_shared: for userspace poll support */

Here.

Either way,
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

>         struct dma_buf_poll_cb_t {
>                 struct dma_fence_cb cb;
>                 wait_queue_head_t *poll;
> @@ -349,7 +403,12 @@ struct dma_buf {
>                 __poll_t active;
>         } cb_excl, cb_shared;
>  #ifdef CONFIG_DMABUF_SYSFS_STATS
> -       /* for sysfs stats */
> +       /**
> +        * @sysfs_entry:
> +        *
> +        * For exposing information about this buffer in sysfs. See also
> +        * `DMA-BUF statistics`_ for the uapi this enables.
> +        */
>         struct dma_buf_sysfs_entry {
>                 struct kobject kobj;
>                 struct dma_buf *dmabuf;
> --
> 2.32.0.rc2
>

Re: [PATCH 01/15] dma-resv: Fix kerneldoc

[Daniel Vetter]

On Tue, Jun 22, 2021 at 8:50 PM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Daniel,
>
> On Tue, Jun 22, 2021 at 06:54:57PM +0200, Daniel Vetter wrote:
> > Oversight from
> >
> > commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9
> > Author: Christian König <christian.koenig@amd.com>
> > Date:   Mon May 10 16:14:09 2021 +0200
>
> this is what we uses Fixes: ... for.
>
> It looks wrong to hide it in the description.

I've honestly become a bit vary of using Fixes: for docs/comments
because the stable autoselect bots are _really_ keen on picking up
anything with a Fixes: line in it. And that feels a bit like nonsense.
-Daniel

>
>         Sam
>
> >
> >     dma-buf: rename and cleanup dma_resv_get_excl v3
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Sumit Semwal <sumit.semwal@linaro.org>
> > Cc: "Christian König" <christian.koenig@amd.com>
> > Cc: linux-media@vger.kernel.org
> > Cc: linaro-mm-sig@lists.linaro.org
> > ---
> >  include/linux/dma-resv.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
> > index 562b885cf9c3..e1ca2080a1ff 100644
> > --- a/include/linux/dma-resv.h
> > +++ b/include/linux/dma-resv.h
> > @@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
> >  }
> >
> >  /**
> > - * dma_resv_exclusive - return the object's exclusive fence
> > + * dma_resv_excl_fence - return the object's exclusive fence
> >   * @obj: the reservation object
> >   *
> >   * Returns the exclusive fence (if any). Caller must either hold the objects
> > --
> > 2.32.0.rc2



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 02/15] dma-buf: Switch to inline kerneldoc

[Daniel Vetter]

On Tue, Jun 22, 2021 at 9:01 PM Sam Ravnborg <sam@ravnborg.org> wrote:
>
> Hi Daniel.
>
> On Tue, Jun 22, 2021 at 06:54:58PM +0200, Daniel Vetter wrote:
> > Also review & update everything while we're at it.
> >
> > This is prep work to smash a ton of stuff into the kerneldoc for
> > @resv.
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Sumit Semwal <sumit.semwal@linaro.org>
> > Cc: "Christian König" <christian.koenig@amd.com>
> > Cc: Alex Deucher <alexander.deucher@amd.com>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Dave Airlie <airlied@redhat.com>
> > Cc: Nirmoy Das <nirmoy.das@amd.com>
> > Cc: Deepak R Varma <mh12gx2825@gmail.com>
> > Cc: Chen Li <chenli@uniontech.com>
> > Cc: Kevin Wang <kevin1.wang@amd.com>
> > Cc: linux-media@vger.kernel.org
> > Cc: linaro-mm-sig@lists.linaro.org
> > ---
> >  include/linux/dma-buf.h | 107 +++++++++++++++++++++++++++++++---------
> >  1 file changed, 83 insertions(+), 24 deletions(-)
> >
> > diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> > index 92eec38a03aa..6d18b9e448b9 100644
> > --- a/include/linux/dma-buf.h
> > +++ b/include/linux/dma-buf.h
> > @@ -289,28 +289,6 @@ struct dma_buf_ops {
> >
> >  /**
> >   * struct dma_buf - shared buffer object
> > - * @size: size of the buffer; invariant over the lifetime of the buffer.
> > - * @file: file pointer used for sharing buffers across, and for refcounting.
> > - * @attachments: list of dma_buf_attachment that denotes all devices attached,
> > - *               protected by dma_resv lock.
> > - * @ops: dma_buf_ops associated with this buffer object.
> > - * @lock: used internally to serialize list manipulation, attach/detach and
> > - *        vmap/unmap
> > - * @vmapping_counter: used internally to refcnt the vmaps
> > - * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
> > - * @exp_name: name of the exporter; useful for debugging.
> > - * @name: userspace-provided name; useful for accounting and debugging,
> > - *        protected by @resv.
> > - * @name_lock: spinlock to protect name access
> > - * @owner: pointer to exporter module; used for refcounting when exporter is a
> > - *         kernel module.
> > - * @list_node: node for dma_buf accounting and debugging.
> > - * @priv: exporter specific private data for this buffer object.
> > - * @resv: reservation object linked to this dma-buf
> > - * @poll: for userspace poll support
> > - * @cb_excl: for userspace poll support
> > - * @cb_shared: for userspace poll support
> > - * @sysfs_entry: for exposing information about this buffer in sysfs.
>
> This sentence
> >   * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
> >   * and is incremented on each attach.
> belongs to the paragraph describing sysfs_entry and should be moved too.
> Or maybe reworded and then document all fields in dma_buf_sysfs_entry?

Unfortunately kerneldoc lost the ability to document embedded
structs/unions. At least last time I checked, it's a bit a bikeshed.
So I'd need to pull the entire struct out. I'll just move it since
it's indeed misplaced.

> With this fixed:
> Acked-by: Sam Ravnborg <sam@ravnborg.org>

Thanks for taking a look.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 01/15] dma-resv: Fix kerneldoc

[Christian König]

Am 22.06.21 um 18:54 schrieb Daniel Vetter:
> Oversight from
>
> commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9
> Author: Christian König <christian.koenig@amd.com>
> Date:   Mon May 10 16:14:09 2021 +0200
>
>      dma-buf: rename and cleanup dma_resv_get_excl v3
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   include/linux/dma-resv.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
> index 562b885cf9c3..e1ca2080a1ff 100644
> --- a/include/linux/dma-resv.h
> +++ b/include/linux/dma-resv.h
> @@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
>   }
>   
>   /**
> - * dma_resv_exclusive - return the object's exclusive fence
> + * dma_resv_excl_fence - return the object's exclusive fence
>    * @obj: the reservation object
>    *
>    * Returns the exclusive fence (if any). Caller must either hold the objects

Re: [PATCH 02/15] dma-buf: Switch to inline kerneldoc

[Christian König]

Am 22.06.21 um 18:54 schrieb Daniel Vetter:
> Also review & update everything while we're at it.
>
> This is prep work to smash a ton of stuff into the kerneldoc for
> @resv.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: Nirmoy Das <nirmoy.das@amd.com>
> Cc: Deepak R Varma <mh12gx2825@gmail.com>
> Cc: Chen Li <chenli@uniontech.com>
> Cc: Kevin Wang <kevin1.wang@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org

Acked-by: Christian König <christian.koenig@amd.com>

> ---
>   include/linux/dma-buf.h | 107 +++++++++++++++++++++++++++++++---------
>   1 file changed, 83 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 92eec38a03aa..6d18b9e448b9 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -289,28 +289,6 @@ struct dma_buf_ops {
>   
>   /**
>    * struct dma_buf - shared buffer object
> - * @size: size of the buffer; invariant over the lifetime of the buffer.
> - * @file: file pointer used for sharing buffers across, and for refcounting.
> - * @attachments: list of dma_buf_attachment that denotes all devices attached,
> - *               protected by dma_resv lock.
> - * @ops: dma_buf_ops associated with this buffer object.
> - * @lock: used internally to serialize list manipulation, attach/detach and
> - *        vmap/unmap
> - * @vmapping_counter: used internally to refcnt the vmaps
> - * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
> - * @exp_name: name of the exporter; useful for debugging.
> - * @name: userspace-provided name; useful for accounting and debugging,
> - *        protected by @resv.
> - * @name_lock: spinlock to protect name access
> - * @owner: pointer to exporter module; used for refcounting when exporter is a
> - *         kernel module.
> - * @list_node: node for dma_buf accounting and debugging.
> - * @priv: exporter specific private data for this buffer object.
> - * @resv: reservation object linked to this dma-buf
> - * @poll: for userspace poll support
> - * @cb_excl: for userspace poll support
> - * @cb_shared: for userspace poll support
> - * @sysfs_entry: for exposing information about this buffer in sysfs.
>    * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
>    * and is incremented on each attach.
>    *
> @@ -324,24 +302,100 @@ struct dma_buf_ops {
>    * Device DMA access is handled by the separate &struct dma_buf_attachment.
>    */
>   struct dma_buf {
> +	/**
> +	 * @size:
> +	 *
> +	 * Size of the buffer; invariant over the lifetime of the buffer.
> +	 */
>   	size_t size;
> +
> +	/**
> +	 * @file:
> +	 *
> +	 * File pointer used for sharing buffers across, and for refcounting.
> +	 * See dma_buf_get() and dma_buf_put().
> +	 */
>   	struct file *file;
> +
> +	/**
> +	 * @attachments:
> +	 *
> +	 * List of dma_buf_attachment that denotes all devices attached,
> +	 * protected by &dma_resv lock @resv.
> +	 */
>   	struct list_head attachments;
> +
> +	/** @ops: dma_buf_ops associated with this buffer object. */
>   	const struct dma_buf_ops *ops;
> +
> +	/**
> +	 * @lock:
> +	 *
> +	 * Used internally to serialize list manipulation, attach/detach and
> +	 * vmap/unmap. Note that in many cases this is superseeded by
> +	 * dma_resv_lock() on @resv.
> +	 */
>   	struct mutex lock;
> +
> +	/**
> +	 * @vmapping_counter:
> +	 *
> +	 * Used internally to refcnt the vmaps returned by dma_buf_vmap().
> +	 * Protected by @lock.
> +	 */
>   	unsigned vmapping_counter;
> +
> +	/**
> +	 * @vmap_ptr:
> +	 * The current vmap ptr if @vmapping_counter > 0. Protected by @lock.
> +	 */
>   	struct dma_buf_map vmap_ptr;
> +
> +	/**
> +	 * @exp_name:
> +	 *
> +	 * Name of the exporter; useful for debugging. See the
> +	 * DMA_BUF_SET_NAME IOCTL.
> +	 */
>   	const char *exp_name;
> +
> +	/**
> +	 * @name:
> +	 *
> +	 * Userspace-provided name; useful for accounting and debugging,
> +	 * protected by dma_resv_lock() on @resv and @name_lock for read access.
> +	 */
>   	const char *name;
> +
> +	/** @name_lock: Spinlock to protect name acces for read access. */
>   	spinlock_t name_lock;
> +
> +	/**
> +	 * @owner:
> +	 *
> +	 * Pointer to exporter module; used for refcounting when exporter is a
> +	 * kernel module.
> +	 */
>   	struct module *owner;
> +
> +	/** @list_node: node for dma_buf accounting and debugging. */
>   	struct list_head list_node;
> +
> +	/** @priv: exporter specific private data for this buffer object. */
>   	void *priv;
> +
> +	/**
> +	 * @resv:
> +	 *
> +	 * Reservation object linked to this dma-buf.
> +	 */
>   	struct dma_resv *resv;
>   
> -	/* poll support */
> +	/** @poll: for userspace poll support */
>   	wait_queue_head_t poll;
>   
> +	/** @cb_excl: for userspace poll support */
> +	/** @cb_shared: for userspace poll support */
>   	struct dma_buf_poll_cb_t {
>   		struct dma_fence_cb cb;
>   		wait_queue_head_t *poll;
> @@ -349,7 +403,12 @@ struct dma_buf {
>   		__poll_t active;
>   	} cb_excl, cb_shared;
>   #ifdef CONFIG_DMABUF_SYSFS_STATS
> -	/* for sysfs stats */
> +	/**
> +	 * @sysfs_entry:
> +	 *
> +	 * For exposing information about this buffer in sysfs. See also
> +	 * `DMA-BUF statistics`_ for the uapi this enables.
> +	 */
>   	struct dma_buf_sysfs_entry {
>   		struct kobject kobj;
>   		struct dma_buf *dmabuf;

Re: [PATCH 01/15] dma-resv: Fix kerneldoc

[Daniel Vetter]

On Wed, Jun 23, 2021 at 10:31:18AM +0200, Christian König wrote:
> Am 22.06.21 um 18:54 schrieb Daniel Vetter:
> > Oversight from
> > 
> > commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9
> > Author: Christian König <christian.koenig@amd.com>
> > Date:   Mon May 10 16:14:09 2021 +0200
> > 
> >      dma-buf: rename and cleanup dma_resv_get_excl v3
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Sumit Semwal <sumit.semwal@linaro.org>
> > Cc: "Christian König" <christian.koenig@amd.com>
> > Cc: linux-media@vger.kernel.org
> > Cc: linaro-mm-sig@lists.linaro.org
> 
> Reviewed-by: Christian König <christian.koenig@amd.com>

Pushed to drm-misc-next.
-Daniel

> 
> > ---
> >   include/linux/dma-resv.h | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
> > index 562b885cf9c3..e1ca2080a1ff 100644
> > --- a/include/linux/dma-resv.h
> > +++ b/include/linux/dma-resv.h
> > @@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
> >   }
> >   /**
> > - * dma_resv_exclusive - return the object's exclusive fence
> > + * dma_resv_excl_fence - return the object's exclusive fence
> >    * @obj: the reservation object
> >    *
> >    * Returns the exclusive fence (if any). Caller must either hold the objects
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

[PATCH] dma-buf: Switch to inline kerneldoc

[Daniel Vetter]

Also review & update everything while we're at it.

This is prep work to smash a ton of stuff into the kerneldoc for
@resv.

v2: Move the doc for sysfs_entry.attachment_uid to the right place too
(Sam)

Acked-by: Christian König <christian.koenig@amd.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Nirmoy Das <nirmoy.das@amd.com>
Cc: Deepak R Varma <mh12gx2825@gmail.com>
Cc: Chen Li <chenli@uniontech.com>
Cc: Kevin Wang <kevin1.wang@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
---
 include/linux/dma-buf.h | 116 +++++++++++++++++++++++++++++++---------
 1 file changed, 90 insertions(+), 26 deletions(-)

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 92eec38a03aa..81cebf414505 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -289,30 +289,6 @@ struct dma_buf_ops {
 
 /**
  * struct dma_buf - shared buffer object
- * @size: size of the buffer; invariant over the lifetime of the buffer.
- * @file: file pointer used for sharing buffers across, and for refcounting.
- * @attachments: list of dma_buf_attachment that denotes all devices attached,
- *               protected by dma_resv lock.
- * @ops: dma_buf_ops associated with this buffer object.
- * @lock: used internally to serialize list manipulation, attach/detach and
- *        vmap/unmap
- * @vmapping_counter: used internally to refcnt the vmaps
- * @vmap_ptr: the current vmap ptr if vmapping_counter > 0
- * @exp_name: name of the exporter; useful for debugging.
- * @name: userspace-provided name; useful for accounting and debugging,
- *        protected by @resv.
- * @name_lock: spinlock to protect name access
- * @owner: pointer to exporter module; used for refcounting when exporter is a
- *         kernel module.
- * @list_node: node for dma_buf accounting and debugging.
- * @priv: exporter specific private data for this buffer object.
- * @resv: reservation object linked to this dma-buf
- * @poll: for userspace poll support
- * @cb_excl: for userspace poll support
- * @cb_shared: for userspace poll support
- * @sysfs_entry: for exposing information about this buffer in sysfs.
- * The attachment_uid member of @sysfs_entry is protected by dma_resv lock
- * and is incremented on each attach.
  *
  * This represents a shared buffer, created by calling dma_buf_export(). The
  * userspace representation is a normal file descriptor, which can be created by
@@ -324,24 +300,100 @@ struct dma_buf_ops {
  * Device DMA access is handled by the separate &struct dma_buf_attachment.
  */
 struct dma_buf {
+	/**
+	 * @size:
+	 *
+	 * Size of the buffer; invariant over the lifetime of the buffer.
+	 */
 	size_t size;
+
+	/**
+	 * @file:
+	 *
+	 * File pointer used for sharing buffers across, and for refcounting.
+	 * See dma_buf_get() and dma_buf_put().
+	 */
 	struct file *file;
+
+	/**
+	 * @attachments:
+	 *
+	 * List of dma_buf_attachment that denotes all devices attached,
+	 * protected by &dma_resv lock @resv.
+	 */
 	struct list_head attachments;
+
+	/** @ops: dma_buf_ops associated with this buffer object. */
 	const struct dma_buf_ops *ops;
+
+	/**
+	 * @lock:
+	 *
+	 * Used internally to serialize list manipulation, attach/detach and
+	 * vmap/unmap. Note that in many cases this is superseeded by
+	 * dma_resv_lock() on @resv.
+	 */
 	struct mutex lock;
+
+	/**
+	 * @vmapping_counter:
+	 *
+	 * Used internally to refcnt the vmaps returned by dma_buf_vmap().
+	 * Protected by @lock.
+	 */
 	unsigned vmapping_counter;
+
+	/**
+	 * @vmap_ptr:
+	 * The current vmap ptr if @vmapping_counter > 0. Protected by @lock.
+	 */
 	struct dma_buf_map vmap_ptr;
+
+	/**
+	 * @exp_name:
+	 *
+	 * Name of the exporter; useful for debugging. See the
+	 * DMA_BUF_SET_NAME IOCTL.
+	 */
 	const char *exp_name;
+
+	/**
+	 * @name:
+	 *
+	 * Userspace-provided name; useful for accounting and debugging,
+	 * protected by dma_resv_lock() on @resv and @name_lock for read access.
+	 */
 	const char *name;
+
+	/** @name_lock: Spinlock to protect name acces for read access. */
 	spinlock_t name_lock;
+
+	/**
+	 * @owner:
+	 *
+	 * Pointer to exporter module; used for refcounting when exporter is a
+	 * kernel module.
+	 */
 	struct module *owner;
+
+	/** @list_node: node for dma_buf accounting and debugging. */
 	struct list_head list_node;
+
+	/** @priv: exporter specific private data for this buffer object. */
 	void *priv;
+
+	/**
+	 * @resv:
+	 *
+	 * Reservation object linked to this dma-buf.
+	 */
 	struct dma_resv *resv;
 
-	/* poll support */
+	/** @poll: for userspace poll support */
 	wait_queue_head_t poll;
 
+	/** @cb_excl: for userspace poll support */
+	/** @cb_shared: for userspace poll support */
 	struct dma_buf_poll_cb_t {
 		struct dma_fence_cb cb;
 		wait_queue_head_t *poll;
@@ -349,10 +401,22 @@ struct dma_buf {
 		__poll_t active;
 	} cb_excl, cb_shared;
 #ifdef CONFIG_DMABUF_SYSFS_STATS
-	/* for sysfs stats */
+	/**
+	 * @sysfs_entry:
+	 *
+	 * For exposing information about this buffer in sysfs. See also
+	 * `DMA-BUF statistics`_ for the uapi this enables.
+	 */
 	struct dma_buf_sysfs_entry {
 		struct kobject kobj;
 		struct dma_buf *dmabuf;
+
+		/**
+		 * @sysfs_entry.attachment_uid:
+		 *
+		 * This is protected by the dma_resv_lock() on @resv and is
+		 * incremented on each attach.
+		 */
 		unsigned int attachment_uid;
 		struct kset *attach_stats_kset;
 	} *sysfs_entry;
-- 
2.32.0.rc2

Re: [PATCH 06/15] drm/panfrost: Fix implicit sync

[Boris Brezillon]

On Tue, 22 Jun 2021 18:55:02 +0200
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:

> Currently this has no practial relevance I think because there's not
> many who can pull off a setup with panfrost and another gpu in the
> same system. But the rules are that if you're setting an exclusive
> fence, indicating a gpu write access in the implicit fencing system,
> then you need to wait for all fences, not just the previous exclusive
> fence.
> 
> panfrost against itself has no problem, because it always sets the
> exclusive fence (but that's probably something that will need to be
> fixed for vulkan and/or multi-engine gpus, or you'll suffer badly).
> Also no problem with that against display.
> 
> With the prep work done to switch over to the dependency helpers this
> is now a oneliner.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> ---
>  drivers/gpu/drm/panfrost/panfrost_job.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 71cd43fa1b36..ef004d587dc4 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -203,9 +203,8 @@ static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
>  	int i, ret;
>  
>  	for (i = 0; i < bo_count; i++) {
> -		struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
> -
> -		ret = drm_gem_fence_array_add(deps, fence);
> +		/* panfrost always uses write mode in its current uapi */
> +		ret = drm_gem_fence_array_add_implicit(deps, bos[i], true);
>  		if (ret)
>  			return ret;
>  	}

Re: [PATCH 05/15] drm/panfrost: Use xarray and helpers for depedency tracking

[Boris Brezillon]

On Tue, 22 Jun 2021 18:55:01 +0200
Daniel Vetter <daniel.vetter@ffwll.ch> wrote:

> More consistency and prep work for the next patch.
> 
> Aside: I wonder whether we shouldn't just move this entire xarray
> business into the scheduler so that not everyone has to reinvent the
> same wheels. Cc'ing some scheduler people for this too.
> 
> v2: Correctly handle sched_lock since Lucas pointed out it's needed.
> 
> v3: Rebase, dma_resv_get_excl_unlocked got renamed
> 
> v4: Don't leak job references on failure (Steven).

Hehe, I had pretty much the same patch here [1].

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

[1]https://patchwork.kernel.org/project/dri-devel/patch/20210311092539.2405596-3-boris.brezillon@collabora.com/

> 
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: Luben Tuikov <luben.tuikov@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Steven Price <steven.price@arm.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: linux-media@vger.kernel.org
> Cc: linaro-mm-sig@lists.linaro.org
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_drv.c | 41 +++++++---------
>  drivers/gpu/drm/panfrost/panfrost_job.c | 65 +++++++++++--------------
>  drivers/gpu/drm/panfrost/panfrost_job.h |  8 ++-
>  3 files changed, 49 insertions(+), 65 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 075ec0ef746c..3ee828f1e7a5 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -138,12 +138,6 @@ panfrost_lookup_bos(struct drm_device *dev,
>  	if (!job->bo_count)
>  		return 0;
>  
> -	job->implicit_fences = kvmalloc_array(job->bo_count,
> -				  sizeof(struct dma_fence *),
> -				  GFP_KERNEL | __GFP_ZERO);
> -	if (!job->implicit_fences)
> -		return -ENOMEM;
> -
>  	ret = drm_gem_objects_lookup(file_priv,
>  				     (void __user *)(uintptr_t)args->bo_handles,
>  				     job->bo_count, &job->bos);
> @@ -174,7 +168,7 @@ panfrost_lookup_bos(struct drm_device *dev,
>  }
>  
>  /**
> - * panfrost_copy_in_sync() - Sets up job->in_fences[] with the sync objects
> + * panfrost_copy_in_sync() - Sets up job->deps with the sync objects
>   * referenced by the job.
>   * @dev: DRM device
>   * @file_priv: DRM file for this fd
> @@ -194,22 +188,14 @@ panfrost_copy_in_sync(struct drm_device *dev,
>  {
>  	u32 *handles;
>  	int ret = 0;
> -	int i;
> +	int i, in_fence_count;
>  
> -	job->in_fence_count = args->in_sync_count;
> +	in_fence_count = args->in_sync_count;
>  
> -	if (!job->in_fence_count)
> +	if (!in_fence_count)
>  		return 0;
>  
> -	job->in_fences = kvmalloc_array(job->in_fence_count,
> -					sizeof(struct dma_fence *),
> -					GFP_KERNEL | __GFP_ZERO);
> -	if (!job->in_fences) {
> -		DRM_DEBUG("Failed to allocate job in fences\n");
> -		return -ENOMEM;
> -	}
> -
> -	handles = kvmalloc_array(job->in_fence_count, sizeof(u32), GFP_KERNEL);
> +	handles = kvmalloc_array(in_fence_count, sizeof(u32), GFP_KERNEL);
>  	if (!handles) {
>  		ret = -ENOMEM;
>  		DRM_DEBUG("Failed to allocate incoming syncobj handles\n");
> @@ -218,16 +204,23 @@ panfrost_copy_in_sync(struct drm_device *dev,
>  
>  	if (copy_from_user(handles,
>  			   (void __user *)(uintptr_t)args->in_syncs,
> -			   job->in_fence_count * sizeof(u32))) {
> +			   in_fence_count * sizeof(u32))) {
>  		ret = -EFAULT;
>  		DRM_DEBUG("Failed to copy in syncobj handles\n");
>  		goto fail;
>  	}
>  
> -	for (i = 0; i < job->in_fence_count; i++) {
> +	for (i = 0; i < in_fence_count; i++) {
> +		struct dma_fence *fence;
> +
>  		ret = drm_syncobj_find_fence(file_priv, handles[i], 0, 0,
> -					     &job->in_fences[i]);
> -		if (ret == -EINVAL)
> +					     &fence);
> +		if (ret)
> +			goto fail;
> +
> +		ret = drm_gem_fence_array_add(&job->deps, fence);
> +
> +		if (ret)
>  			goto fail;
>  	}
>  
> @@ -265,6 +258,8 @@ static int panfrost_ioctl_submit(struct drm_device *dev, void *data,
>  
>  	kref_init(&job->refcount);
>  
> +	xa_init_flags(&job->deps, XA_FLAGS_ALLOC);
> +
>  	job->pfdev = pfdev;
>  	job->jc = args->jc;
>  	job->requirements = args->requirements;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 38f8580c19f1..71cd43fa1b36 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -196,14 +196,21 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>  	job_write(pfdev, JS_COMMAND_NEXT(js), JS_COMMAND_START);
>  }
>  
> -static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
> -					   int bo_count,
> -					   struct dma_fence **implicit_fences)
> +static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
> +					  int bo_count,
> +					  struct xarray *deps)
>  {
> -	int i;
> +	int i, ret;
>  
> -	for (i = 0; i < bo_count; i++)
> -		implicit_fences[i] = dma_resv_get_excl_unlocked(bos[i]->resv);
> +	for (i = 0; i < bo_count; i++) {
> +		struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
> +
> +		ret = drm_gem_fence_array_add(deps, fence);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
>  }
>  
>  static void panfrost_attach_object_fences(struct drm_gem_object **bos,
> @@ -240,10 +247,14 @@ int panfrost_job_push(struct panfrost_job *job)
>  
>  	job->render_done_fence = dma_fence_get(&job->base.s_fence->finished);
>  
> -	kref_get(&job->refcount); /* put by scheduler job completion */
> +	ret = panfrost_acquire_object_fences(job->bos, job->bo_count,
> +					     &job->deps);
> +	if (ret) {
> +		mutex_unlock(&pfdev->sched_lock);
> +		goto unlock;
> +	}
>  
> -	panfrost_acquire_object_fences(job->bos, job->bo_count,
> -				       job->implicit_fences);
> +	kref_get(&job->refcount); /* put by scheduler job completion */
>  
>  	drm_sched_entity_push_job(&job->base, entity);
>  
> @@ -262,18 +273,15 @@ static void panfrost_job_cleanup(struct kref *ref)
>  {
>  	struct panfrost_job *job = container_of(ref, struct panfrost_job,
>  						refcount);
> +	struct dma_fence *fence;
> +	unsigned long index;
>  	unsigned int i;
>  
> -	if (job->in_fences) {
> -		for (i = 0; i < job->in_fence_count; i++)
> -			dma_fence_put(job->in_fences[i]);
> -		kvfree(job->in_fences);
> -	}
> -	if (job->implicit_fences) {
> -		for (i = 0; i < job->bo_count; i++)
> -			dma_fence_put(job->implicit_fences[i]);
> -		kvfree(job->implicit_fences);
> +	xa_for_each(&job->deps, index, fence) {
> +		dma_fence_put(fence);
>  	}
> +	xa_destroy(&job->deps);
> +
>  	dma_fence_put(job->done_fence);
>  	dma_fence_put(job->render_done_fence);
>  
> @@ -316,26 +324,9 @@ static struct dma_fence *panfrost_job_dependency(struct drm_sched_job *sched_job
>  						 struct drm_sched_entity *s_entity)
>  {
>  	struct panfrost_job *job = to_panfrost_job(sched_job);
> -	struct dma_fence *fence;
> -	unsigned int i;
> -
> -	/* Explicit fences */
> -	for (i = 0; i < job->in_fence_count; i++) {
> -		if (job->in_fences[i]) {
> -			fence = job->in_fences[i];
> -			job->in_fences[i] = NULL;
> -			return fence;
> -		}
> -	}
>  
> -	/* Implicit fences, max. one per BO */
> -	for (i = 0; i < job->bo_count; i++) {
> -		if (job->implicit_fences[i]) {
> -			fence = job->implicit_fences[i];
> -			job->implicit_fences[i] = NULL;
> -			return fence;
> -		}
> -	}
> +	if (!xa_empty(&job->deps))
> +		return xa_erase(&job->deps, job->last_dep++);
>  
>  	return NULL;
>  }
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.h b/drivers/gpu/drm/panfrost/panfrost_job.h
> index bbd3ba97ff67..82306a03b57e 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.h
> @@ -19,9 +19,9 @@ struct panfrost_job {
>  	struct panfrost_device *pfdev;
>  	struct panfrost_file_priv *file_priv;
>  
> -	/* Optional fences userspace can pass in for the job to depend on. */
> -	struct dma_fence **in_fences;
> -	u32 in_fence_count;
> +	/* Contains both explicit and implicit fences */
> +	struct xarray deps;
> +	unsigned long last_dep;
>  
>  	/* Fence to be signaled by IRQ handler when the job is complete. */
>  	struct dma_fence *done_fence;
> @@ -30,8 +30,6 @@ struct panfrost_job {
>  	__u32 requirements;
>  	__u32 flush_id;
>  
> -	/* Exclusive fences we have taken from the BOs to wait for */
> -	struct dma_fence **implicit_fences;
>  	struct panfrost_gem_mapping **mappings;
>  	struct drm_gem_object **bos;
>  	u32 bo_count;

Re: [PATCH 06/15] drm/panfrost: Fix implicit sync

[Daniel Vetter]

On Wed, Jun 23, 2021 at 06:47:37PM +0200, Boris Brezillon wrote:
> On Tue, 22 Jun 2021 18:55:02 +0200
> Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> 
> > Currently this has no practial relevance I think because there's not
> > many who can pull off a setup with panfrost and another gpu in the
> > same system. But the rules are that if you're setting an exclusive
> > fence, indicating a gpu write access in the implicit fencing system,
> > then you need to wait for all fences, not just the previous exclusive
> > fence.
> > 
> > panfrost against itself has no problem, because it always sets the
> > exclusive fence (but that's probably something that will need to be
> > fixed for vulkan and/or multi-engine gpus, or you'll suffer badly).
> > Also no problem with that against display.
> > 
> > With the prep work done to switch over to the dependency helpers this
> > is now a oneliner.
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
> > Cc: Steven Price <steven.price@arm.com>
> > Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> > Cc: Sumit Semwal <sumit.semwal@linaro.org>
> 
> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

Pushed the 3 panfrost patches to drm-misc-next, thanks for reviewing them.
-Daniel

> 
> > Cc: "Christian König" <christian.koenig@amd.com>
> > Cc: linux-media@vger.kernel.org
> > Cc: linaro-mm-sig@lists.linaro.org
> > ---
> >  drivers/gpu/drm/panfrost/panfrost_job.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> > index 71cd43fa1b36..ef004d587dc4 100644
> > --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> > @@ -203,9 +203,8 @@ static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
> >  	int i, ret;
> >  
> >  	for (i = 0; i < bo_count; i++) {
> > -		struct dma_fence *fence = dma_resv_get_excl_unlocked(bos[i]->resv);
> > -
> > -		ret = drm_gem_fence_array_add(deps, fence);
> > +		/* panfrost always uses write mode in its current uapi */
> > +		ret = drm_gem_fence_array_add_implicit(deps, bos[i], true);
> >  		if (ret)
> >  			return ret;
> >  	}
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch