[PATCH] dma-buf: Add support for mapping buffers with DMA attributes

From: Guangming Cao <redacted>

When mapping the memory represented by a dma-buf into a device's
address space, it might be desireable to map the memory with
certain DMA attributes. Thus, introduce the dma_mapping_attrs
field in the dma_buf_attachment structure so that when
the memory is mapped with dma_buf_map_attachment, it is mapped
with the desired DMA attributes.

Signed-off-by: Isaac J. Manjarres <redacted>
Signed-off-by: Sandeep Patil <redacted>
Signed-off-by: Guangming Cao <redacted>
---
 drivers/dma-buf/heaps/cma_heap.c    | 6 ++++--
 drivers/dma-buf/heaps/system_heap.c | 6 ++++--
 include/linux/dma-buf.h             | 3 +++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index 0c05b79870f9..2c9feb3bfc3e 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c

@@ -99,9 +99,10 @@ static struct sg_table *cma_heap_map_dma_buf(struct dma_buf_attachment *attachme
 {
 	struct dma_heap_attachment *a = attachment->priv;
 	struct sg_table *table = &a->table;
+	int attrs = attachment->dma_map_attrs;
 	int ret;
 
-	ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+	ret = dma_map_sgtable(attachment->dev, table, direction, attrs);
 	if (ret)
 		return ERR_PTR(-ENOMEM);
 	a->mapped = true;

@@ -113,9 +114,10 @@ static void cma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
 				   enum dma_data_direction direction)
 {
 	struct dma_heap_attachment *a = attachment->priv;
+	int attrs = attachment->dma_map_attrs;
 
 	a->mapped = false;
-	dma_unmap_sgtable(attachment->dev, table, direction, 0);
+	dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 23a7e74ef966..fc7b1e02988e 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c

@@ -130,9 +130,10 @@ static struct sg_table *system_heap_map_dma_buf(struct dma_buf_attachment *attac
 {
 	struct dma_heap_attachment *a = attachment->priv;
 	struct sg_table *table = a->table;
+	int attrs = attachment->dma_map_attrs;
 	int ret;
 
-	ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+	ret = dma_map_sgtable(attachment->dev, table, direction, attrs);
 	if (ret)
 		return ERR_PTR(ret);
 

@@ -145,9 +146,10 @@ static void system_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
 				      enum dma_data_direction direction)
 {
 	struct dma_heap_attachment *a = attachment->priv;
+	int attrs = attachment->dma_map_attrs;
 
 	a->mapped = false;
-	dma_unmap_sgtable(attachment->dev, table, direction, 0);
+	dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int system_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index efdc56b9d95f..4d650731766e 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h

@@ -379,6 +379,8 @@ struct dma_buf_attach_ops {
  * @importer_ops: importer operations for this attachment, if provided
  * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held.
  * @importer_priv: importer specific attachment data.
+ * @dma_map_attrs: DMA attributes to be used when the exporter maps the buffer
+ * through dma_buf_map_attachment.
  *
  * This structure holds the attachment information between the dma_buf buffer
  * and its user device(s). The list contains one attachment struct per device

@@ -399,6 +401,7 @@ struct dma_buf_attachment {
 	const struct dma_buf_attach_ops *importer_ops;
 	void *importer_priv;
 	void *priv;
+	unsigned long dma_map_attrs;
 };
 
 /**

-- 
2.17.1
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On Mon, Aug 30, 2021 at 10:39:11AM +0800, guangming.cao@mediatek.com wrote:

From: Guangming Cao <redacted>

When mapping the memory represented by a dma-buf into a device's
address space, it might be desireable to map the memory with
certain DMA attributes. Thus, introduce the dma_mapping_attrs
field in the dma_buf_attachment structure so that when
the memory is mapped with dma_buf_map_attachment, it is mapped
with the desired DMA attributes.

Signed-off-by: Isaac J. Manjarres <redacted>
Signed-off-by: Sandeep Patil <redacted>
Signed-off-by: Guangming Cao <redacted>

Can you pls include the code that's going to use this here too?

At a glance all the attributes you might want to set are supposed to be
under the control of the exporter, not the importer.
-Daniel

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

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On Tue, 2021-08-31 at 14:47 +0200, Daniel Vetter wrote:

On Mon, Aug 30, 2021 at 10:39:11AM +0800, guangming.cao@mediatek.com
wrote:

quoted

From: Guangming Cao <redacted>

When mapping the memory represented by a dma-buf into a device's
address space, it might be desireable to map the memory with
certain DMA attributes. Thus, introduce the dma_mapping_attrs
field in the dma_buf_attachment structure so that when
the memory is mapped with dma_buf_map_attachment, it is mapped
with the desired DMA attributes.

Signed-off-by: Isaac J. Manjarres <redacted>
Signed-off-by: Sandeep Patil <redacted>
Signed-off-by: Guangming Cao <redacted>

Can you pls include the code that's going to use this here too?

At a glance all the attributes you might want to set are supposed to
be
under the control of the exporter, not the importer.
-Daniel

Hi Daniel,

Sorry for late. Currently I couldn't upload the coding going to use
this part because of some miscellaneous reasons.

Just as I said in commit message, for dma_heap, users can't skip cache
sync or other opetrations when map iova[dma_buf_map_attachment] by
fill (struct dma_buf_attachment).dma_map_attrs, it's not dma_map_attrs
expected(link: 
https://github.com/torvalds/linux/blob/master/Documentation/core-api/dma-attributes.rst#dma_attr_skip_cpu_sync
).

Correspondingly, if they use dma_buf to map iova[dma_buf_map_attrs],
they will not meet this issue. So, I think it's a design flaw for
dma_heap.

BRs!
Guangming

quoted

---
 drivers/dma-buf/heaps/cma_heap.c    | 6 ++++--
 drivers/dma-buf/heaps/system_heap.c | 6 ++++--
 include/linux/dma-buf.h             | 3 +++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-

buf/heaps/cma_heap.c
index 0c05b79870f9..2c9feb3bfc3e 100644

--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c

@@ -99,9 +99,10 @@ static struct sg_table

*cma_heap_map_dma_buf(struct dma_buf_attachment *attachme
 {
 	struct dma_heap_attachment *a = attachment->priv;
 	struct sg_table *table = &a->table;
+	int attrs = attachment->dma_map_attrs;
 	int ret;
 
-	ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+	ret = dma_map_sgtable(attachment->dev, table, direction,
attrs);
 	if (ret)
 		return ERR_PTR(-ENOMEM);
 	a->mapped = true;

@@ -113,9 +114,10 @@ static void cma_heap_unmap_dma_buf(struct

dma_buf_attachment *attachment,
 				   enum dma_data_direction direction)
 {
 	struct dma_heap_attachment *a = attachment->priv;
+	int attrs = attachment->dma_map_attrs;
 
 	a->mapped = false;
-	dma_unmap_sgtable(attachment->dev, table, direction, 0);
+	dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf
*dmabuf,

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-

buf/heaps/system_heap.c
index 23a7e74ef966..fc7b1e02988e 100644

--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c

@@ -130,9 +130,10 @@ static struct sg_table

*system_heap_map_dma_buf(struct dma_buf_attachment *attac
 {
 	struct dma_heap_attachment *a = attachment->priv;
 	struct sg_table *table = a->table;
+	int attrs = attachment->dma_map_attrs;
 	int ret;
 
-	ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+	ret = dma_map_sgtable(attachment->dev, table, direction,
attrs);
 	if (ret)
 		return ERR_PTR(ret);
 

@@ -145,9 +146,10 @@ static void system_heap_unmap_dma_buf(struct

dma_buf_attachment *attachment,
 				      enum dma_data_direction
direction)
 {
 	struct dma_heap_attachment *a = attachment->priv;
+	int attrs = attachment->dma_map_attrs;
 
 	a->mapped = false;
-	dma_unmap_sgtable(attachment->dev, table, direction, 0);
+	dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int system_heap_dma_buf_begin_cpu_access(struct dma_buf
*dmabuf,

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index efdc56b9d95f..4d650731766e 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h

@@ -379,6 +379,8 @@ struct dma_buf_attach_ops {
  * @importer_ops: importer operations for this attachment, if

provided
  * dma_buf_map/unmap_attachment() must be called with the dma_resv
lock held.
  * @importer_priv: importer specific attachment data.
+ * @dma_map_attrs: DMA attributes to be used when the exporter
maps the buffer
+ * through dma_buf_map_attachment.
  *
  * This structure holds the attachment information between the
dma_buf buffer
  * and its user device(s). The list contains one attachment struct
per device

@@ -399,6 +401,7 @@ struct dma_buf_attachment {
 	const struct dma_buf_attach_ops *importer_ops;
 	void *importer_priv;
 	void *priv;
+	unsigned long dma_map_attrs;
 };
 
 /**

-- 
2.17.1

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From: Guangming Cao <redacted>

On Tue, 2021-08-31 at 14:47 +0200, Daniel Vetter wrote:

On Mon, Aug 30, 2021 at 10:39:11AM +0800, guangming.cao@mediatek.com
wrote:

quoted

From: Guangming Cao <redacted>

When mapping the memory represented by a dma-buf into a device's
address space, it might be desireable to map the memory with
certain DMA attributes. Thus, introduce the dma_mapping_attrs
field in the dma_buf_attachment structure so that when
the memory is mapped with dma_buf_map_attachment, it is mapped
with the desired DMA attributes.

Signed-off-by: Isaac J. Manjarres <redacted>
Signed-off-by: Sandeep Patil <redacted>
Signed-off-by: Guangming Cao <redacted>

Can you pls include the code that's going to use this here too?

At a glance all the attributes you might want to set are supposed to
be
under the control of the exporter, not the importer.
-Daniel

Hi Daniel,

Sorry for the late. Currently I couldn't upload the coding going to use
this part because of some miscellaneous reasons.

Just as I said in commit message, for dma_heap, users can't skip cache
sync or other opetrations when map iova[dma_buf_map_attachment] by
fill (struct dma_buf_attachment).dma_map_attrs, it's not dma_map_attrs
expected(link: 
https://github.com/torvalds/linux/blob/master/Documentation/core-api/dma-attributes.rst#dma_attr_skip_cpu_sync
).

Correspondingly, if they use dma_buf to map iova[dma_buf_map_attrs],
they will not meet this issue. So, I think it's a design flaw for
dma_heap.

BRs!
Guangming

quoted

---
 drivers/dma-buf/heaps/cma_heap.c    | 6 ++++--
 drivers/dma-buf/heaps/system_heap.c | 6 ++++--
 include/linux/dma-buf.h             | 3 +++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-

buf/heaps/cma_heap.c
index 0c05b79870f9..2c9feb3bfc3e 100644

--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c

@@ -99,9 +99,10 @@ static struct sg_table

*cma_heap_map_dma_buf(struct dma_buf_attachment *attachme
 {
    struct dma_heap_attachment *a = attachment->priv;
    struct sg_table *table = &a->table;
+   int attrs = attachment->dma_map_attrs;
    int ret;
 
-   ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+   ret = dma_map_sgtable(attachment->dev, table, direction,
attrs);
    if (ret)
            return ERR_PTR(-ENOMEM);
    a->mapped = true;

@@ -113,9 +114,10 @@ static void cma_heap_unmap_dma_buf(struct

dma_buf_attachment *attachment,
                               enum dma_data_direction direction)
 {
    struct dma_heap_attachment *a = attachment->priv;
+   int attrs = attachment->dma_map_attrs;
 
    a->mapped = false;
-   dma_unmap_sgtable(attachment->dev, table, direction, 0);
+   dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf
*dmabuf,

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-

buf/heaps/system_heap.c
index 23a7e74ef966..fc7b1e02988e 100644

--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c

@@ -130,9 +130,10 @@ static struct sg_table

*system_heap_map_dma_buf(struct dma_buf_attachment *attac
 {
    struct dma_heap_attachment *a = attachment->priv;
    struct sg_table *table = a->table;
+   int attrs = attachment->dma_map_attrs;
    int ret;
 
-   ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+   ret = dma_map_sgtable(attachment->dev, table, direction,
attrs);
    if (ret)
            return ERR_PTR(ret);
 

@@ -145,9 +146,10 @@ static void system_heap_unmap_dma_buf(struct

dma_buf_attachment *attachment,
                                  enum dma_data_direction
direction)
 {
    struct dma_heap_attachment *a = attachment->priv;
+   int attrs = attachment->dma_map_attrs;
 
    a->mapped = false;
-   dma_unmap_sgtable(attachment->dev, table, direction, 0);
+   dma_unmap_sgtable(attachment->dev, table, direction, attrs);
 }
 
 static int system_heap_dma_buf_begin_cpu_access(struct dma_buf
*dmabuf,

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index efdc56b9d95f..4d650731766e 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h

@@ -379,6 +379,8 @@ struct dma_buf_attach_ops {
  * @importer_ops: importer operations for this attachment, if

provided
  * dma_buf_map/unmap_attachment() must be called with the dma_resv
lock held.
  * @importer_priv: importer specific attachment data.
+ * @dma_map_attrs: DMA attributes to be used when the exporter
maps the buffer
+ * through dma_buf_map_attachment.
  *
  * This structure holds the attachment information between the
dma_buf buffer
  * and its user device(s). The list contains one attachment struct
per device

@@ -399,6 +401,7 @@ struct dma_buf_attachment {
    const struct dma_buf_attach_ops *importer_ops;
    void *importer_priv;
    void *priv;
+   unsigned long dma_map_attrs;
 };
 
 /**

-- 
2.17.1

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