[PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[Sumit Semwal]

At present, dma_buf_export() takes a series of parameters, which
makes it difficult to add any new parameters for exporters, if required.

Make it simpler by moving all these parameters into a struct, and pass
the struct * as parameter to dma_buf_export().

While at it, unite dma_buf_export_named() with dma_buf_export(), and
change all callers accordingly.

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
---
v3: Daniel Thompson caught the C99 warning issue w/ using {0}; using
    {.exp_name = xxx} instead.

v2: add macro to zero out local struct, and fill KBUILD_MODNAME by default

 drivers/dma-buf/dma-buf.c                      | 47 +++++++++++++-------------
 drivers/gpu/drm/armada/armada_gem.c            | 10 ++++--
 drivers/gpu/drm/drm_prime.c                    | 12 ++++---
 drivers/gpu/drm/exynos/exynos_drm_dmabuf.c     |  9 +++--
 drivers/gpu/drm/i915/i915_gem_dmabuf.c         | 10 ++++--
 drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c      |  9 ++++-
 drivers/gpu/drm/tegra/gem.c                    | 10 ++++--
 drivers/gpu/drm/ttm/ttm_object.c               |  9 +++--
 drivers/gpu/drm/udl/udl_dmabuf.c               |  9 ++++-
 drivers/media/v4l2-core/videobuf2-dma-contig.c |  8 ++++-
 drivers/media/v4l2-core/videobuf2-dma-sg.c     |  8 ++++-
 drivers/media/v4l2-core/videobuf2-vmalloc.c    |  8 ++++-
 drivers/staging/android/ion/ion.c              |  9 +++--
 include/linux/dma-buf.h                        | 34 +++++++++++++++----
 14 files changed, 142 insertions(+), 50 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 5be225c2ba98..6d3df3dd9310 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -265,7 +265,7 @@ static inline int is_dma_buf_file(struct file *file)
 }
 
 /**
- * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
+ * dma_buf_export - Creates a new dma_buf, and associates an anon file
  * with this buffer, so it can be exported.
  * Also connect the allocator specific data and ops to the buffer.
  * Additionally, provide a name string for exporter; useful in debugging.
@@ -277,31 +277,32 @@ static inline int is_dma_buf_file(struct file *file)
  * @exp_name:	[in]	name of the exporting module - useful for debugging.
  * @resv:	[in]	reservation-object, NULL to allocate default one.
  *
+ * All the above info comes from struct dma_buf_export_info.
+ *
  * Returns, on success, a newly created dma_buf object, which wraps the
  * supplied private data and operations for dma_buf_ops. On either missing
  * ops, or error in allocating struct dma_buf, will return negative error.
  *
  */
-struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
-				size_t size, int flags, const char *exp_name,
-				struct reservation_object *resv)
+struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info)
 {
 	struct dma_buf *dmabuf;
 	struct file *file;
 	size_t alloc_size = sizeof(struct dma_buf);
-	if (!resv)
+	if (!exp_info->resv)
 		alloc_size += sizeof(struct reservation_object);
 	else
 		/* prevent &dma_buf[1] == dma_buf->resv */
 		alloc_size += 1;
 
-	if (WARN_ON(!priv || !ops
-			  || !ops->map_dma_buf
-			  || !ops->unmap_dma_buf
-			  || !ops->release
-			  || !ops->kmap_atomic
-			  || !ops->kmap
-			  || !ops->mmap)) {
+	if (WARN_ON(!exp_info->priv
+			  || !exp_info->ops
+			  || !exp_info->ops->map_dma_buf
+			  || !exp_info->ops->unmap_dma_buf
+			  || !exp_info->ops->release
+			  || !exp_info->ops->kmap_atomic
+			  || !exp_info->ops->kmap
+			  || !exp_info->ops->mmap)) {
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -309,21 +310,22 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
 	if (dmabuf == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	dmabuf->priv = priv;
-	dmabuf->ops = ops;
-	dmabuf->size = size;
-	dmabuf->exp_name = exp_name;
+	dmabuf->priv = exp_info->priv;
+	dmabuf->ops = exp_info->ops;
+	dmabuf->size = exp_info->size;
+	dmabuf->exp_name = exp_info->exp_name;
 	init_waitqueue_head(&dmabuf->poll);
 	dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
 	dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
 
-	if (!resv) {
-		resv = (struct reservation_object *)&dmabuf[1];
-		reservation_object_init(resv);
+	if (!exp_info->resv) {
+		exp_info->resv = (struct reservation_object *)&dmabuf[1];
+		reservation_object_init(exp_info->resv);
 	}
-	dmabuf->resv = resv;
+	dmabuf->resv = exp_info->resv;
 
-	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
+					exp_info->flags);
 	if (IS_ERR(file)) {
 		kfree(dmabuf);
 		return ERR_CAST(file);
@@ -341,8 +343,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
 
 	return dmabuf;
 }
-EXPORT_SYMBOL_GPL(dma_buf_export_named);
-
+EXPORT_SYMBOL_GPL(dma_buf_export);
 
 /**
  * dma_buf_fd - returns a file descriptor for the given dma_buf
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index ef5feeecec84..580e10acaa3a 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -538,8 +538,14 @@ struct dma_buf *
 armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj,
 	int flags)
 {
-	return dma_buf_export(obj, &armada_gem_prime_dmabuf_ops, obj->size,
-			      O_RDWR, NULL);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &armada_gem_prime_dmabuf_ops;
+	exp_info.size = obj->size;
+	exp_info.flags = O_RDWR;
+	exp_info.priv = obj;
+
+	return dma_buf_export(&exp_info);
 }
 
 struct drm_gem_object *
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 7482b06cd08f..7fec191b45f7 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -339,13 +339,17 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
 struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
 				     struct drm_gem_object *obj, int flags)
 {
-	struct reservation_object *robj = NULL;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &drm_gem_prime_dmabuf_ops;
+	exp_info.size = obj->size;
+	exp_info.flags = flags;
+	exp_info.priv = obj;
 
 	if (dev->driver->gem_prime_res_obj)
-		robj = dev->driver->gem_prime_res_obj(obj);
+		exp_info.resv = dev->driver->gem_prime_res_obj(obj);
 
-	return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
-			      flags, robj);
+	return dma_buf_export(&exp_info);
 }
 EXPORT_SYMBOL(drm_gem_prime_export);
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index 60192ed544f0..fc293a179f36 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -185,9 +185,14 @@ struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
 				struct drm_gem_object *obj, int flags)
 {
 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 
-	return dma_buf_export(obj, &exynos_dmabuf_ops,
-				exynos_gem_obj->base.size, flags, NULL);
+	exp_info.ops = &exynos_dmabuf_ops;
+	exp_info.size = exynos_gem_obj->base.size;
+	exp_info.flags = flags;
+	exp_info.priv = obj;
+
+	return dma_buf_export(&exp_info);
 }
 
 struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 82a1f4b57778..7998da27c500 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -230,6 +230,13 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
 				      struct drm_gem_object *gem_obj, int flags)
 {
 	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &i915_dmabuf_ops;
+	exp_info.size = gem_obj->size;
+	exp_info.flags = flags;
+	exp_info.priv = gem_obj;
+
 
 	if (obj->ops->dmabuf_export) {
 		int ret = obj->ops->dmabuf_export(obj);
@@ -237,8 +244,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
 			return ERR_PTR(ret);
 	}
 
-	return dma_buf_export(gem_obj, &i915_dmabuf_ops, gem_obj->size, flags,
-			      NULL);
+	return dma_buf_export(&exp_info);
 }
 
 static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index a2dbfb1737b4..5874c58e72c1 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -171,7 +171,14 @@ static struct dma_buf_ops omap_dmabuf_ops = {
 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
 		struct drm_gem_object *obj, int flags)
 {
-	return dma_buf_export(obj, &omap_dmabuf_ops, obj->size, flags, NULL);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &omap_dmabuf_ops;
+	exp_info.size = obj->size;
+	exp_info.flags = flags;
+	exp_info.priv = obj;
+
+	return dma_buf_export(&exp_info);
 }
 
 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 8777b7f75791..1f895b953f8f 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -658,8 +658,14 @@ struct dma_buf *tegra_gem_prime_export(struct drm_device *drm,
 				       struct drm_gem_object *gem,
 				       int flags)
 {
-	return dma_buf_export(gem, &tegra_gem_prime_dmabuf_ops, gem->size,
-			      flags, NULL);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &tegra_gem_prime_dmabuf_ops;
+	exp_info.size = gem->size;
+	exp_info.flags = flags;
+	exp_info.priv = gem;
+
+	return dma_buf_export(&exp_info);
 }
 
 struct drm_gem_object *tegra_gem_prime_import(struct drm_device *drm,
diff --git a/drivers/gpu/drm/ttm/ttm_object.c b/drivers/gpu/drm/ttm/ttm_object.c
index 12c87110db3a..4f5fa8d65fe9 100644
--- a/drivers/gpu/drm/ttm/ttm_object.c
+++ b/drivers/gpu/drm/ttm/ttm_object.c
@@ -683,6 +683,12 @@ int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 
 	dma_buf = prime->dma_buf;
 	if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
+		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+		exp_info.ops = &tdev->ops;
+		exp_info.size = prime->size;
+		exp_info.flags = flags;
+		exp_info.priv = prime;
 
 		/*
 		 * Need to create a new dma_buf, with memory accounting.
@@ -694,8 +700,7 @@ int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 			goto out_unref;
 		}
 
-		dma_buf = dma_buf_export(prime, &tdev->ops,
-					 prime->size, flags, NULL);
+		dma_buf = dma_buf_export(&exp_info);
 		if (IS_ERR(dma_buf)) {
 			ret = PTR_ERR(dma_buf);
 			ttm_mem_global_free(tdev->mem_glob,
diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c
index ac8a66b4dfc2..e2243edd1ce3 100644
--- a/drivers/gpu/drm/udl/udl_dmabuf.c
+++ b/drivers/gpu/drm/udl/udl_dmabuf.c
@@ -202,7 +202,14 @@ static struct dma_buf_ops udl_dmabuf_ops = {
 struct dma_buf *udl_gem_prime_export(struct drm_device *dev,
 				     struct drm_gem_object *obj, int flags)
 {
-	return dma_buf_export(obj, &udl_dmabuf_ops, obj->size, flags, NULL);
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &udl_dmabuf_ops;
+	exp_info.size = obj->size;
+	exp_info.flags = flags;
+	exp_info.priv = obj;
+
+	return dma_buf_export(&exp_info);
 }
 
 static int udl_prime_create(struct drm_device *dev,
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index b481d20c8372..4ad92a147919 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -402,6 +402,12 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
 {
 	struct vb2_dc_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &vb2_dc_dmabuf_ops;
+	exp_info.size = buf->size;
+	exp_info.flags = flags;
+	exp_info.priv = buf;
 
 	if (!buf->sgt_base)
 		buf->sgt_base = vb2_dc_get_base_sgt(buf);
@@ -409,7 +415,7 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
 	if (WARN_ON(!buf->sgt_base))
 		return NULL;
 
-	dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, flags, NULL);
+	dbuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dbuf))
 		return NULL;
 
diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index b1838abb6d00..45c708e463b9 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -583,11 +583,17 @@ static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags
 {
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &vb2_dma_sg_dmabuf_ops;
+	exp_info.size = buf->size;
+	exp_info.flags = flags;
+	exp_info.priv = buf;
 
 	if (WARN_ON(!buf->dma_sgt))
 		return NULL;
 
-	dbuf = dma_buf_export(buf, &vb2_dma_sg_dmabuf_ops, buf->size, flags, NULL);
+	dbuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dbuf))
 		return NULL;
 
diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index fba944e50227..992b1b59409c 100644
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -367,11 +367,17 @@ static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flag
 {
 	struct vb2_vmalloc_buf *buf = buf_priv;
 	struct dma_buf *dbuf;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &vb2_vmalloc_dmabuf_ops;
+	exp_info.size = buf->size;
+	exp_info.flags = flags;
+	exp_info.priv = buf;
 
 	if (WARN_ON(!buf->vaddr))
 		return NULL;
 
-	dbuf = dma_buf_export(buf, &vb2_vmalloc_dmabuf_ops, buf->size, flags, NULL);
+	dbuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dbuf))
 		return NULL;
 
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 296d347660fc..a4297be8f12f 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -1106,6 +1106,12 @@ struct dma_buf *ion_share_dma_buf(struct ion_client *client,
 	struct ion_buffer *buffer;
 	struct dma_buf *dmabuf;
 	bool valid_handle;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+
+	exp_info.ops = &dma_buf_ops;
+	exp_info.size = buffer->size;
+	exp_info.flags = O_RDWR;
+	exp_info.priv = buffer;
 
 	mutex_lock(&client->lock);
 	valid_handle = ion_handle_validate(client, handle);
@@ -1118,8 +1124,7 @@ struct dma_buf *ion_share_dma_buf(struct ion_client *client,
 	ion_buffer_get(buffer);
 	mutex_unlock(&client->lock);
 
-	dmabuf = dma_buf_export(buffer, &dma_buf_ops, buffer->size, O_RDWR,
-				NULL);
+	dmabuf = dma_buf_export(&exp_info);
 	if (IS_ERR(dmabuf)) {
 		ion_buffer_put(buffer);
 		return dmabuf;
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 694e1fe1c4b4..a4e395eeffef 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -163,6 +163,33 @@ struct dma_buf_attachment {
 };
 
 /**
+ * struct dma_buf_export_info - holds information needed to export a dma_buf
+ * @exp_name:	name of the exporting module - useful for debugging.
+ * @ops:	Attach allocator-defined dma buf ops to the new buffer
+ * @size:	Size of the buffer
+ * @flags:	mode flags for the file
+ * @resv:	reservation-object, NULL to allocate default one
+ * @priv:	Attach private data of allocator to this buffer
+ *
+ * This structure holds the information required to export the buffer. Used
+ * with dma_buf_export() only.
+ */
+struct dma_buf_export_info {
+	const char *exp_name;
+	const struct dma_buf_ops *ops;
+	size_t size;
+	int flags;
+	struct reservation_object *resv;
+	void *priv;
+};
+
+/**
+ * helper macro for exporters; zeros and fills in most common values
+ */
+#define DEFINE_DMA_BUF_EXPORT_INFO(a)	\
+	struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME }
+
+/**
  * get_dma_buf - convenience wrapper for get_file.
  * @dmabuf:	[in]	pointer to dma_buf
  *
@@ -181,12 +208,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 void dma_buf_detach(struct dma_buf *dmabuf,
 				struct dma_buf_attachment *dmabuf_attach);
 
-struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
-			       size_t size, int flags, const char *,
-			       struct reservation_object *);
-
-#define dma_buf_export(priv, ops, size, flags, resv)	\
-	dma_buf_export_named(priv, ops, size, flags, KBUILD_MODNAME, resv)
+struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info);
 
 int dma_buf_fd(struct dma_buf *dmabuf, int flags);
 struct dma_buf *dma_buf_get(int fd);
-- 
1.9.1

Re: [PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[Mauro Carvalho Chehab]

Em Wed, 28 Jan 2015 18:24:03 +0530
Sumit Semwal <sumit.semwal@linaro.org> escreveu:

> +/**
> + * helper macro for exporters; zeros and fills in most common values
> + */
> +#define DEFINE_DMA_BUF_EXPORT_INFO(a)	\
> +	struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME }
> +

I suspect that this will let the other fields not initialized.

You likely need to do:

#define DEFINE_DMA_BUF_EXPORT_INFO(a)	\
	struct dma_buf_export_info a = { 	\
	.exp_name = KBUILD_MODNAME;		\
	.fields = 0;				\
...
}

Regards,
Mauro

Re: [PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[Sumit Semwal]

Hi Mauro,

On 28 January 2015 at 18:53, Mauro Carvalho Chehab
<mchehab@osg.samsung.com> wrote:
> Em Wed, 28 Jan 2015 18:24:03 +0530
> Sumit Semwal <sumit.semwal@linaro.org> escreveu:
>
>> +/**
>> + * helper macro for exporters; zeros and fills in most common values
>> + */
>> +#define DEFINE_DMA_BUF_EXPORT_INFO(a)        \
>> +     struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME }
>> +
>
> I suspect that this will let the other fields not initialized.
>
> You likely need to do:
>
> #define DEFINE_DMA_BUF_EXPORT_INFO(a)   \
>         struct dma_buf_export_info a = {        \
>         .exp_name = KBUILD_MODNAME;             \
>         .fields = 0;                            \
> ...
> }
I suspected the same, but Daniel kindly referred to the C99 standard,
which states:
" If there are fewer initializers in a brace-enclosed list than there
are elements or members
of an aggregate, or fewer characters in a string literal used to
initialize an array of known
size than there are elements in the array, the remainder of the
aggregate shall be
initialized implicitly the same as objects that have static storage duration."

So I think we're well covered there?
>
> Regards,
> Mauro



-- 
Thanks and regards,

Sumit Semwal
Kernel Team Lead - Linaro Mobile Group
Linaro.org │ Open source software for ARM SoCs

Re: [PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[Maarten Lankhorst]

Op 28-01-15 om 13:54 schreef Sumit Semwal:
> At present, dma_buf_export() takes a series of parameters, which
> makes it difficult to add any new parameters for exporters, if required.
>
> Make it simpler by moving all these parameters into a struct, and pass
> the struct * as parameter to dma_buf_export().
>
> While at it, unite dma_buf_export_named() with dma_buf_export(), and
> change all callers accordingly.
>
> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
> ---
> v3: Daniel Thompson caught the C99 warning issue w/ using {0}; using
>     {.exp_name = xxx} instead.
>
> v2: add macro to zero out local struct, and fill KBUILD_MODNAME by default
>
>  drivers/dma-buf/dma-buf.c                      | 47 +++++++++++++-------------
>  drivers/gpu/drm/armada/armada_gem.c            | 10 ++++--
>  drivers/gpu/drm/drm_prime.c                    | 12 ++++---
>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c     |  9 +++--
>  drivers/gpu/drm/i915/i915_gem_dmabuf.c         | 10 ++++--
>  drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c      |  9 ++++-
>  drivers/gpu/drm/tegra/gem.c                    | 10 ++++--
>  drivers/gpu/drm/ttm/ttm_object.c               |  9 +++--
>  drivers/gpu/drm/udl/udl_dmabuf.c               |  9 ++++-
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |  8 ++++-
>  drivers/media/v4l2-core/videobuf2-dma-sg.c     |  8 ++++-
>  drivers/media/v4l2-core/videobuf2-vmalloc.c    |  8 ++++-
>  drivers/staging/android/ion/ion.c              |  9 +++--
>  include/linux/dma-buf.h                        | 34 +++++++++++++++----
>  14 files changed, 142 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 5be225c2ba98..6d3df3dd9310 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -265,7 +265,7 @@ static inline int is_dma_buf_file(struct file *file)
>  }
>  
>  /**
> - * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
> + * dma_buf_export - Creates a new dma_buf, and associates an anon file
>   * with this buffer, so it can be exported.
>   * Also connect the allocator specific data and ops to the buffer.
>   * Additionally, provide a name string for exporter; useful in debugging.
> @@ -277,31 +277,32 @@ static inline int is_dma_buf_file(struct file *file)
>   * @exp_name:	[in]	name of the exporting module - useful for debugging.
>   * @resv:	[in]	reservation-object, NULL to allocate default one.
>   *
> + * All the above info comes from struct dma_buf_export_info.
> + *
>   * Returns, on success, a newly created dma_buf object, which wraps the
>   * supplied private data and operations for dma_buf_ops. On either missing
>   * ops, or error in allocating struct dma_buf, will return negative error.
>   *
>   */
> -struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
> -				size_t size, int flags, const char *exp_name,
> -				struct reservation_object *resv)
> +struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info)
This function should probably take a const struct dma_buf_export_info here..

Rest looks sane.

~Maarten


>  {
>  	struct dma_buf *dmabuf;
>  	struct file *file;
>  	size_t alloc_size = sizeof(struct dma_buf);
> -	if (!resv)
> +	if (!exp_info->resv)
>  		alloc_size += sizeof(struct reservation_object);
>  	else
>  		/* prevent &dma_buf[1] == dma_buf->resv */
>  		alloc_size += 1;
>  
> -	if (WARN_ON(!priv || !ops
> -			  || !ops->map_dma_buf
> -			  || !ops->unmap_dma_buf
> -			  || !ops->release
> -			  || !ops->kmap_atomic
> -			  || !ops->kmap
> -			  || !ops->mmap)) {
> +	if (WARN_ON(!exp_info->priv
> +			  || !exp_info->ops
> +			  || !exp_info->ops->map_dma_buf
> +			  || !exp_info->ops->unmap_dma_buf
> +			  || !exp_info->ops->release
> +			  || !exp_info->ops->kmap_atomic
> +			  || !exp_info->ops->kmap
> +			  || !exp_info->ops->mmap)) {
>  		return ERR_PTR(-EINVAL);
>  	}
>  
> @@ -309,21 +310,22 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
>  	if (dmabuf == NULL)
>  		return ERR_PTR(-ENOMEM);
>  
> -	dmabuf->priv = priv;
> -	dmabuf->ops = ops;
> -	dmabuf->size = size;
> -	dmabuf->exp_name = exp_name;
> +	dmabuf->priv = exp_info->priv;
> +	dmabuf->ops = exp_info->ops;
> +	dmabuf->size = exp_info->size;
> +	dmabuf->exp_name = exp_info->exp_name;
>  	init_waitqueue_head(&dmabuf->poll);
>  	dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
>  	dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
>  
> -	if (!resv) {
> -		resv = (struct reservation_object *)&dmabuf[1];
> -		reservation_object_init(resv);
> +	if (!exp_info->resv) {
> +		exp_info->resv = (struct reservation_object *)&dmabuf[1];
> +		reservation_object_init(exp_info->resv);
>  	}
> -	dmabuf->resv = resv;
> +	dmabuf->resv = exp_info->resv;
>  
> -	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
> +	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
> +					exp_info->flags);
>  	if (IS_ERR(file)) {
>  		kfree(dmabuf);
>  		return ERR_CAST(file);
> @@ -341,8 +343,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
>  
>  	return dmabuf;
>  }
> -EXPORT_SYMBOL_GPL(dma_buf_export_named);
> -
> +EXPORT_SYMBOL_GPL(dma_buf_export);
>  
>  /**
>   * dma_buf_fd - returns a file descriptor for the given dma_buf
> diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
> index ef5feeecec84..580e10acaa3a 100644
> --- a/drivers/gpu/drm/armada/armada_gem.c
> +++ b/drivers/gpu/drm/armada/armada_gem.c
> @@ -538,8 +538,14 @@ struct dma_buf *
>  armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj,
>  	int flags)
>  {
> -	return dma_buf_export(obj, &armada_gem_prime_dmabuf_ops, obj->size,
> -			      O_RDWR, NULL);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &armada_gem_prime_dmabuf_ops;
> +	exp_info.size = obj->size;
> +	exp_info.flags = O_RDWR;
> +	exp_info.priv = obj;
> +
> +	return dma_buf_export(&exp_info);
>  }
>  
>  struct drm_gem_object *
> diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
> index 7482b06cd08f..7fec191b45f7 100644
> --- a/drivers/gpu/drm/drm_prime.c
> +++ b/drivers/gpu/drm/drm_prime.c
> @@ -339,13 +339,17 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =  {
>  struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
>  				     struct drm_gem_object *obj, int flags)
>  {
> -	struct reservation_object *robj = NULL;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &drm_gem_prime_dmabuf_ops;
> +	exp_info.size = obj->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = obj;
>  
>  	if (dev->driver->gem_prime_res_obj)
> -		robj = dev->driver->gem_prime_res_obj(obj);
> +		exp_info.resv = dev->driver->gem_prime_res_obj(obj);
>  
> -	return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
> -			      flags, robj);
> +	return dma_buf_export(&exp_info);
>  }
>  EXPORT_SYMBOL(drm_gem_prime_export);
>  
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> index 60192ed544f0..fc293a179f36 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> @@ -185,9 +185,14 @@ struct dma_buf *exynos_dmabuf_prime_export(struct drm_device *drm_dev,
>  				struct drm_gem_object *obj, int flags)
>  {
>  	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
>  
> -	return dma_buf_export(obj, &exynos_dmabuf_ops,
> -				exynos_gem_obj->base.size, flags, NULL);
> +	exp_info.ops = &exynos_dmabuf_ops;
> +	exp_info.size = exynos_gem_obj->base.size;
> +	exp_info.flags = flags;
> +	exp_info.priv = obj;
> +
> +	return dma_buf_export(&exp_info);
>  }
>  
>  struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> index 82a1f4b57778..7998da27c500 100644
> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> @@ -230,6 +230,13 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
>  				      struct drm_gem_object *gem_obj, int flags)
>  {
>  	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &i915_dmabuf_ops;
> +	exp_info.size = gem_obj->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = gem_obj;
> +
>  
>  	if (obj->ops->dmabuf_export) {
>  		int ret = obj->ops->dmabuf_export(obj);
> @@ -237,8 +244,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
>  			return ERR_PTR(ret);
>  	}
>  
> -	return dma_buf_export(gem_obj, &i915_dmabuf_ops, gem_obj->size, flags,
> -			      NULL);
> +	return dma_buf_export(&exp_info);
>  }
>  
>  static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
> diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
> index a2dbfb1737b4..5874c58e72c1 100644
> --- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
> +++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
> @@ -171,7 +171,14 @@ static struct dma_buf_ops omap_dmabuf_ops = {
>  struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
>  		struct drm_gem_object *obj, int flags)
>  {
> -	return dma_buf_export(obj, &omap_dmabuf_ops, obj->size, flags, NULL);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &omap_dmabuf_ops;
> +	exp_info.size = obj->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = obj;
> +
> +	return dma_buf_export(&exp_info);
>  }
>  
>  struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
> diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> index 8777b7f75791..1f895b953f8f 100644
> --- a/drivers/gpu/drm/tegra/gem.c
> +++ b/drivers/gpu/drm/tegra/gem.c
> @@ -658,8 +658,14 @@ struct dma_buf *tegra_gem_prime_export(struct drm_device *drm,
>  				       struct drm_gem_object *gem,
>  				       int flags)
>  {
> -	return dma_buf_export(gem, &tegra_gem_prime_dmabuf_ops, gem->size,
> -			      flags, NULL);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &tegra_gem_prime_dmabuf_ops;
> +	exp_info.size = gem->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = gem;
> +
> +	return dma_buf_export(&exp_info);
>  }
>  
>  struct drm_gem_object *tegra_gem_prime_import(struct drm_device *drm,
> diff --git a/drivers/gpu/drm/ttm/ttm_object.c b/drivers/gpu/drm/ttm/ttm_object.c
> index 12c87110db3a..4f5fa8d65fe9 100644
> --- a/drivers/gpu/drm/ttm/ttm_object.c
> +++ b/drivers/gpu/drm/ttm/ttm_object.c
> @@ -683,6 +683,12 @@ int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
>  
>  	dma_buf = prime->dma_buf;
>  	if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
> +		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +		exp_info.ops = &tdev->ops;
> +		exp_info.size = prime->size;
> +		exp_info.flags = flags;
> +		exp_info.priv = prime;
>  
>  		/*
>  		 * Need to create a new dma_buf, with memory accounting.
> @@ -694,8 +700,7 @@ int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
>  			goto out_unref;
>  		}
>  
> -		dma_buf = dma_buf_export(prime, &tdev->ops,
> -					 prime->size, flags, NULL);
> +		dma_buf = dma_buf_export(&exp_info);
>  		if (IS_ERR(dma_buf)) {
>  			ret = PTR_ERR(dma_buf);
>  			ttm_mem_global_free(tdev->mem_glob,
> diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c
> index ac8a66b4dfc2..e2243edd1ce3 100644
> --- a/drivers/gpu/drm/udl/udl_dmabuf.c
> +++ b/drivers/gpu/drm/udl/udl_dmabuf.c
> @@ -202,7 +202,14 @@ static struct dma_buf_ops udl_dmabuf_ops = {
>  struct dma_buf *udl_gem_prime_export(struct drm_device *dev,
>  				     struct drm_gem_object *obj, int flags)
>  {
> -	return dma_buf_export(obj, &udl_dmabuf_ops, obj->size, flags, NULL);
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &udl_dmabuf_ops;
> +	exp_info.size = obj->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = obj;
> +
> +	return dma_buf_export(&exp_info);
>  }
>  
>  static int udl_prime_create(struct drm_device *dev,
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> index b481d20c8372..4ad92a147919 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -402,6 +402,12 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
>  {
>  	struct vb2_dc_buf *buf = buf_priv;
>  	struct dma_buf *dbuf;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &vb2_dc_dmabuf_ops;
> +	exp_info.size = buf->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = buf;
>  
>  	if (!buf->sgt_base)
>  		buf->sgt_base = vb2_dc_get_base_sgt(buf);
> @@ -409,7 +415,7 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
>  	if (WARN_ON(!buf->sgt_base))
>  		return NULL;
>  
> -	dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, flags, NULL);
> +	dbuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dbuf))
>  		return NULL;
>  
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> index b1838abb6d00..45c708e463b9 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> @@ -583,11 +583,17 @@ static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags
>  {
>  	struct vb2_dma_sg_buf *buf = buf_priv;
>  	struct dma_buf *dbuf;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &vb2_dma_sg_dmabuf_ops;
> +	exp_info.size = buf->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = buf;
>  
>  	if (WARN_ON(!buf->dma_sgt))
>  		return NULL;
>  
> -	dbuf = dma_buf_export(buf, &vb2_dma_sg_dmabuf_ops, buf->size, flags, NULL);
> +	dbuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dbuf))
>  		return NULL;
>  
> diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> index fba944e50227..992b1b59409c 100644
> --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
> +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> @@ -367,11 +367,17 @@ static struct dma_buf *vb2_vmalloc_get_dmabuf(void *buf_priv, unsigned long flag
>  {
>  	struct vb2_vmalloc_buf *buf = buf_priv;
>  	struct dma_buf *dbuf;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &vb2_vmalloc_dmabuf_ops;
> +	exp_info.size = buf->size;
> +	exp_info.flags = flags;
> +	exp_info.priv = buf;
>  
>  	if (WARN_ON(!buf->vaddr))
>  		return NULL;
>  
> -	dbuf = dma_buf_export(buf, &vb2_vmalloc_dmabuf_ops, buf->size, flags, NULL);
> +	dbuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dbuf))
>  		return NULL;
>  
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 296d347660fc..a4297be8f12f 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -1106,6 +1106,12 @@ struct dma_buf *ion_share_dma_buf(struct ion_client *client,
>  	struct ion_buffer *buffer;
>  	struct dma_buf *dmabuf;
>  	bool valid_handle;
> +	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
> +
> +	exp_info.ops = &dma_buf_ops;
> +	exp_info.size = buffer->size;
> +	exp_info.flags = O_RDWR;
> +	exp_info.priv = buffer;
>  
>  	mutex_lock(&client->lock);
>  	valid_handle = ion_handle_validate(client, handle);
> @@ -1118,8 +1124,7 @@ struct dma_buf *ion_share_dma_buf(struct ion_client *client,
>  	ion_buffer_get(buffer);
>  	mutex_unlock(&client->lock);
>  
> -	dmabuf = dma_buf_export(buffer, &dma_buf_ops, buffer->size, O_RDWR,
> -				NULL);
> +	dmabuf = dma_buf_export(&exp_info);
>  	if (IS_ERR(dmabuf)) {
>  		ion_buffer_put(buffer);
>  		return dmabuf;
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 694e1fe1c4b4..a4e395eeffef 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -163,6 +163,33 @@ struct dma_buf_attachment {
>  };
>  
>  /**
> + * struct dma_buf_export_info - holds information needed to export a dma_buf
> + * @exp_name:	name of the exporting module - useful for debugging.
> + * @ops:	Attach allocator-defined dma buf ops to the new buffer
> + * @size:	Size of the buffer
> + * @flags:	mode flags for the file
> + * @resv:	reservation-object, NULL to allocate default one
> + * @priv:	Attach private data of allocator to this buffer
> + *
> + * This structure holds the information required to export the buffer. Used
> + * with dma_buf_export() only.
> + */
> +struct dma_buf_export_info {
> +	const char *exp_name;
> +	const struct dma_buf_ops *ops;
> +	size_t size;
> +	int flags;
> +	struct reservation_object *resv;
> +	void *priv;
> +};
> +
> +/**
> + * helper macro for exporters; zeros and fills in most common values
> + */
> +#define DEFINE_DMA_BUF_EXPORT_INFO(a)	\
> +	struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME }
> +
> +/**
>   * get_dma_buf - convenience wrapper for get_file.
>   * @dmabuf:	[in]	pointer to dma_buf
>   *
> @@ -181,12 +208,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
>  void dma_buf_detach(struct dma_buf *dmabuf,
>  				struct dma_buf_attachment *dmabuf_attach);
>  
> -struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
> -			       size_t size, int flags, const char *,
> -			       struct reservation_object *);
> -
> -#define dma_buf_export(priv, ops, size, flags, resv)	\
> -	dma_buf_export_named(priv, ops, size, flags, KBUILD_MODNAME, resv)
> +struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info);
>  
>  int dma_buf_fd(struct dma_buf *dmabuf, int flags);
>  struct dma_buf *dma_buf_get(int fd);

Re: [PATCH v3] dma-buf: cleanup dma_buf_export() to make it easily extensible

[Daniel Thompson]

On 28/01/15 12:54, Sumit Semwal wrote:
> At present, dma_buf_export() takes a series of parameters, which
> makes it difficult to add any new parameters for exporters, if required.
> 
> Make it simpler by moving all these parameters into a struct, and pass
> the struct * as parameter to dma_buf_export().
> 
> While at it, unite dma_buf_export_named() with dma_buf_export(), and
> change all callers accordingly.
> 
> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

Sorry, a few more comments. Should have sent these before but at least
the are all related only to documentation. Once that is fixed then:
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


> ---
> v3: Daniel Thompson caught the C99 warning issue w/ using {0}; using
>     {.exp_name = xxx} instead.
> 
> v2: add macro to zero out local struct, and fill KBUILD_MODNAME by default
> 
>  drivers/dma-buf/dma-buf.c                      | 47 +++++++++++++-------------
>  drivers/gpu/drm/armada/armada_gem.c            | 10 ++++--
>  drivers/gpu/drm/drm_prime.c                    | 12 ++++---
>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c     |  9 +++--
>  drivers/gpu/drm/i915/i915_gem_dmabuf.c         | 10 ++++--
>  drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c      |  9 ++++-
>  drivers/gpu/drm/tegra/gem.c                    | 10 ++++--
>  drivers/gpu/drm/ttm/ttm_object.c               |  9 +++--
>  drivers/gpu/drm/udl/udl_dmabuf.c               |  9 ++++-
>  drivers/media/v4l2-core/videobuf2-dma-contig.c |  8 ++++-
>  drivers/media/v4l2-core/videobuf2-dma-sg.c     |  8 ++++-
>  drivers/media/v4l2-core/videobuf2-vmalloc.c    |  8 ++++-
>  drivers/staging/android/ion/ion.c              |  9 +++--
>  include/linux/dma-buf.h                        | 34 +++++++++++++++----

Documentation/dma-buf-sharing.txt needs updating as a result of these
changes but its not in the diffstat.


>  14 files changed, 142 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 5be225c2ba98..6d3df3dd9310 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -265,7 +265,7 @@ static inline int is_dma_buf_file(struct file *file)
>  }
>  
>  /**
> - * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
> + * dma_buf_export - Creates a new dma_buf, and associates an anon file
>   * with this buffer, so it can be exported.
>   * Also connect the allocator specific data and ops to the buffer.
>   * Additionally, provide a name string for exporter; useful in debugging.
> @@ -277,31 +277,32 @@ static inline int is_dma_buf_file(struct file *file)
>   * @exp_name:	[in]	name of the exporting module - useful for debugging.
>   * @resv:	[in]	reservation-object, NULL to allocate default one.
>   *
> + * All the above info comes from struct dma_buf_export_info.
> + *

I'm not at all sure about this. Its a novel trick but won't this make
the HTML docs come out looking a bit weird? Is there any prior art for
double-documenting the structure members like this?


Daniel.