[PATCH 1/3] dma-buf: add flags to skip map_dma_buf() for some drivers

oushixiong1025
2025-04-30T08:58:12Z

From: Shixiong Ou <oushixiong@kylinos.cn>

[WHY] Some Importer does not need to call dma_buf_map_attachment() to
get the scatterlist info, especially those drivers of hardware that do
not support DMA, such as the udl, the virtgpu and the ast.

[HOW] skip map_dma_buf() when dma_buf_dynamic_attach() for some drivers.

Signed-off-by: Shixiong Ou <oushixiong@kylinos.cn>
---
drivers/accel/ivpu/ivpu_gem.c | 2 +-
drivers/accel/qaic/qaic_data.c | 2 +-
drivers/dma-buf/dma-buf.c | 29 ++++++++++---------
drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 2 +-
drivers/gpu/drm/armada/armada_gem.c | 2 +-
drivers/gpu/drm/drm_prime.c | 2 +-
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 +-
.../drm/i915/gem/selftests/i915_gem_dmabuf.c | 2 +-
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 2 +-
drivers/gpu/drm/tegra/gem.c | 4 +--
drivers/gpu/drm/virtio/virtgpu_prime.c | 2 +-
drivers/gpu/drm/xe/xe_dma_buf.c | 2 +-
drivers/iio/industrialio-buffer.c | 2 +-
drivers/infiniband/core/umem_dmabuf.c | 3 +-
.../common/videobuf2/videobuf2-dma-contig.c | 2 +-
.../media/common/videobuf2/videobuf2-dma-sg.c | 2 +-
.../platform/nvidia/tegra-vde/dmabuf-cache.c | 2 +-
drivers/misc/fastrpc.c | 2 +-
drivers/usb/gadget/function/f_fs.c | 2 +-
drivers/xen/gntdev-dmabuf.c | 2 +-
include/linux/dma-buf.h | 5 ++--
net/core/devmem.c | 2 +-
22 files changed, 41 insertions(+), 36 deletions(-)

diff --git a/drivers/accel/ivpu/ivpu_gem.c b/drivers/accel/ivpu/ivpu_gem.c
index 8741c73b92ce..5258a66ed945 100644
--- a/drivers/accel/ivpu/ivpu_gem.c
+++ b/drivers/accel/ivpu/ivpu_gem.c
@@ -183,7 +183,7 @@ struct drm_gem_object *ivpu_gem_prime_import(struct drm_device *dev,
struct drm_gem_object *obj;
int ret;

- attach = dma_buf_attach(dma_buf, attach_dev);
+ attach = dma_buf_attach(dma_buf, attach_dev, false);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c
index 43aba57b48f0..c13c64d59143 100644
--- a/drivers/accel/qaic/qaic_data.c
+++ b/drivers/accel/qaic/qaic_data.c
@@ -803,7 +803,7 @@ struct drm_gem_object *qaic_gem_prime_import(struct drm_device *dev, struct dma_
obj = &bo->base;
get_dma_buf(dma_buf);

- attach = dma_buf_attach(dma_buf, dev->dev);
+ attach = dma_buf_attach(dma_buf, dev->dev, false);
if (IS_ERR(attach)) {
ret = PTR_ERR(attach);
goto attach_fail;
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 5baa83b85515..dd7fe5fbf197 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -904,7 +904,7 @@ static struct sg_table *__map_dma_buf(struct dma_buf_attachment *attach,
struct dma_buf_attachment *
dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
const struct dma_buf_attach_ops *importer_ops,
- void *importer_priv)
+ void *importer_priv, bool skip_map)
{
struct dma_buf_attachment *attach;
int ret;
@@ -941,8 +941,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
*/
if (dma_buf_attachment_is_dynamic(attach) !=
dma_buf_is_dynamic(dmabuf)) {
- struct sg_table *sgt;
-
dma_resv_lock(attach->dmabuf->resv, NULL);
if (dma_buf_is_dynamic(attach->dmabuf)) {
ret = dmabuf->ops->pin(attach);
@@ -950,16 +948,20 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
goto err_unlock;
}

- sgt = __map_dma_buf(attach, DMA_BIDIRECTIONAL);
- if (!sgt)
- sgt = ERR_PTR(-ENOMEM);
- if (IS_ERR(sgt)) {
- ret = PTR_ERR(sgt);
- goto err_unpin;
+ if (!skip_map) {
+ struct sg_table *sgt;
+
+ sgt = __map_dma_buf(attach, DMA_BIDIRECTIONAL);
+ if (!sgt)
+ sgt = ERR_PTR(-ENOMEM);
+ if (IS_ERR(sgt)) {
+ ret = PTR_ERR(sgt);
+ goto err_unpin;
+ }
+ attach->sgt = sgt;
+ attach->dir = DMA_BIDIRECTIONAL;
}
dma_resv_unlock(attach->dmabuf->resv);
- attach->sgt = sgt;
- attach->dir = DMA_BIDIRECTIONAL;
}

return attach;
@@ -989,9 +991,10 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, "DMA_BUF");
* mapping.
*/
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
- struct device *dev)
+ struct device *dev,
+ bool skip_map)
{
- return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL);
+ return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL, skip_map);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_attach, "DMA_BUF");

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
index e6913fcf2c7b..26c94834e6d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
@@ -479,7 +479,7 @@ struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
return obj;

attach = dma_buf_dynamic_attach(dma_buf, dev->dev,
- &amdgpu_dma_buf_attach_ops, obj);
+ &amdgpu_dma_buf_attach_ops, obj, false);
if (IS_ERR(attach)) {
drm_gem_object_put(obj);
return ERR_CAST(attach);
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 1a1680d71486..7e1a82828b87 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -514,7 +514,7 @@ armada_gem_prime_import(struct drm_device *dev, struct dma_buf *buf)
}
}

- attach = dma_buf_attach(buf, dev->dev);
+ attach = dma_buf_attach(buf, dev->dev, false);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index bdb51c8f262e..8e70abca33b9 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -949,7 +949,7 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
if (!dev->driver->gem_prime_import_sg_table)
return ERR_PTR(-EINVAL);

- attach = dma_buf_attach(dma_buf, attach_dev);
+ attach = dma_buf_attach(dma_buf, attach_dev, false);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 9473050ac842..6015f6beb8e6 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -305,7 +305,7 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
return ERR_PTR(-E2BIG);

/* need to attach */
- attach = dma_buf_attach(dma_buf, dev->dev);
+ attach = dma_buf_attach(dma_buf, dev->dev, false);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
index 2fda549dd82d..1992241fdf54 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
@@ -287,7 +287,7 @@ static int igt_dmabuf_import_same_driver(struct drm_i915_private *i915,
goto out_import;

/* Now try a fake an importer */
- import_attach = dma_buf_attach(dmabuf, obj->base.dev->dev);
+ import_attach = dma_buf_attach(dmabuf, obj->base.dev->dev, false);
if (IS_ERR(import_attach)) {
err = PTR_ERR(import_attach);
goto out_import;
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 30cf1cdc1aa3..41fb4149409e 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -114,7 +114,7 @@ struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
}
}

- attach = dma_buf_attach(dma_buf, dev->dev);
+ attach = dma_buf_attach(dma_buf, dev->dev, false);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index ace3e5a805cf..e5527c9d10bb 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -79,7 +79,7 @@ static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_
if (obj->dma_buf) {
struct dma_buf *buf = obj->dma_buf;

- map->attach = dma_buf_attach(buf, dev);
+ map->attach = dma_buf_attach(buf, dev, false);
if (IS_ERR(map->attach)) {
err = PTR_ERR(map->attach);
goto free;
@@ -470,7 +470,7 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
* domain, map it first to the DRM device to get an sgt.
*/
if (tegra->domain) {
- attach = dma_buf_attach(buf, drm->dev);
+ attach = dma_buf_attach(buf, drm->dev, false);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto free;
diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
index 4de2a63ccd18..6d9d1fe342b6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -326,7 +326,7 @@ struct drm_gem_object *virtgpu_gem_prime_import(struct drm_device *dev,
drm_gem_private_object_init(dev, obj, buf->size);

attach = dma_buf_dynamic_attach(buf, dev->dev,
- &virtgpu_dma_buf_attach_ops, obj);
+ &virtgpu_dma_buf_attach_ops, obj, true);
if (IS_ERR(attach)) {
kfree(bo);
return ERR_CAST(attach);
diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
index f7a20264ea33..9f524b9ed425 100644
--- a/drivers/gpu/drm/xe/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/xe_dma_buf.c
@@ -293,7 +293,7 @@ struct drm_gem_object *xe_gem_prime_import(struct drm_device *dev,
attach_ops = test->attach_ops;
#endif

- attach = dma_buf_dynamic_attach(dma_buf, dev->dev, attach_ops, &bo->ttm.base);
+ attach = dma_buf_dynamic_attach(dma_buf, dev->dev, attach_ops, &bo->ttm.base, false);
if (IS_ERR(attach)) {
obj = ERR_CAST(attach);
goto out_err;
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index a80f7cc25a27..1296af4c2f7a 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1679,7 +1679,7 @@ static int iio_buffer_attach_dmabuf(struct iio_dev_buffer_pair *ib,
goto err_free_priv;
}

- attach = dma_buf_attach(dmabuf, indio_dev->dev.parent);
+ attach = dma_buf_attach(dmabuf, indio_dev->dev.parent, false);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto err_dmabuf_put;
diff --git a/drivers/infiniband/core/umem_dmabuf.c b/drivers/infiniband/core/umem_dmabuf.c
index 0ec2e4120cc9..ed635c407cbd 100644
--- a/drivers/infiniband/core/umem_dmabuf.c
+++ b/drivers/infiniband/core/umem_dmabuf.c
@@ -159,7 +159,8 @@ ib_umem_dmabuf_get_with_dma_device(struct ib_device *device,
dmabuf,
dma_device,
ops,
- umem_dmabuf);
+ umem_dmabuf,
+ false);
if (IS_ERR(umem_dmabuf->attach)) {
ret = ERR_CAST(umem_dmabuf->attach);
goto out_free_umem;
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index a13ec569c82f..362f5b555ce2 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -786,7 +786,7 @@ static void *vb2_dc_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,
buf->vb = vb;

/* create attachment for the dmabuf with the user device */
- dba = dma_buf_attach(dbuf, buf->dev);
+ dba = dma_buf_attach(dbuf, buf->dev, false);
if (IS_ERR(dba)) {
pr_err("failed to attach dmabuf\n");
kfree(buf);
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index c6ddf2357c58..4f9a4e9783a1 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -632,7 +632,7 @@ static void *vb2_dma_sg_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,

buf->dev = dev;
/* create attachment for the dmabuf with the user device */
- dba = dma_buf_attach(dbuf, buf->dev);
+ dba = dma_buf_attach(dbuf, buf->dev, false);
if (IS_ERR(dba)) {
pr_err("failed to attach dmabuf\n");
kfree(buf);
diff --git a/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c b/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
index b34244ea14dd..d04da2d3e4da 100644
--- a/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
+++ b/drivers/media/platform/nvidia/tegra-vde/dmabuf-cache.c
@@ -95,7 +95,7 @@ int tegra_vde_dmabuf_cache_map(struct tegra_vde *vde,
goto ref;
}

- attachment = dma_buf_attach(dmabuf, dev);
+ attachment = dma_buf_attach(dmabuf, dev, false);
if (IS_ERR(attachment)) {
dev_err(dev, "Failed to attach dmabuf\n");
err = PTR_ERR(attachment);
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 7b7a22c91fe4..aee6f4cbd6c6 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -778,7 +778,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd,
goto get_err;
}

- map->attach = dma_buf_attach(map->buf, sess->dev);
+ map->attach = dma_buf_attach(map->buf, sess->dev, false);
if (IS_ERR(map->attach)) {
dev_err(sess->dev, "Failed to attach dmabuf\n");
err = PTR_ERR(map->attach);
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 2dea9e42a0f8..51926ffdb843 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1487,7 +1487,7 @@ static int ffs_dmabuf_attach(struct file *file, int fd)
if (IS_ERR(dmabuf))
return PTR_ERR(dmabuf);

- attach = dma_buf_attach(dmabuf, gadget->dev.parent);
+ attach = dma_buf_attach(dmabuf, gadget->dev.parent, false);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto err_dmabuf_put;
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
index 5453d86324f6..9de191b6d1f7 100644
--- a/drivers/xen/gntdev-dmabuf.c
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -587,7 +587,7 @@ dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
gntdev_dmabuf->priv = priv;
gntdev_dmabuf->fd = fd;

- attach = dma_buf_attach(dma_buf, dev);
+ attach = dma_buf_attach(dma_buf, dev, false);
if (IS_ERR(attach)) {
ret = ERR_CAST(attach);
goto fail_free_obj;
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 36216d28d8bd..1ea25089b3ba 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -598,11 +598,12 @@ dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach)
}

struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
- struct device *dev);
+ struct device *dev,
+ bool skip_map);
struct dma_buf_attachment *
dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
const struct dma_buf_attach_ops *importer_ops,
- void *importer_priv);
+ void *importer_priv, bool skip_map);
void dma_buf_detach(struct dma_buf *dmabuf,
struct dma_buf_attachment *attach);
int dma_buf_pin(struct dma_buf_attachment *attach);
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 6e27a47d0493..8137ecff9e39 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -202,7 +202,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, unsigned int dmabuf_fd,

binding->dmabuf = dmabuf;

- binding->attachment = dma_buf_attach(binding->dmabuf, dev->dev.parent);
+ binding->attachment = dma_buf_attach(binding->dmabuf, dev->dev.parent, false);
if (IS_ERR(binding->attachment)) {
err = PTR_ERR(binding->attachment);
NL_SET_ERR_MSG(extack, "Failed to bind dmabuf to device");
--
2.17.1