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Subject[PATCH 03/12] dma-buf: lock the reservation object during (un)map_dma_buf v3
Date
Make it mandatory for dynamic dma-buf callbacks to be called with the
reservation lock held.

For static dma-buf exporters we still have the fallback of using cached sgt.

v2: reordered
v3: rebased on sgt caching
v4: use the cached sgt when possible

Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/dma-buf/dma-buf.c | 24 ++++++++++---------
drivers/gpu/drm/armada/armada_gem.c | 6 ++++-
drivers/gpu/drm/drm_prime.c | 6 ++++-
drivers/gpu/drm/i915/i915_gem_dmabuf.c | 6 ++++-
drivers/gpu/drm/tegra/gem.c | 6 ++++-
drivers/gpu/drm/udl/udl_dmabuf.c | 6 ++++-
.../common/videobuf2/videobuf2-dma-contig.c | 6 ++++-
.../media/common/videobuf2/videobuf2-dma-sg.c | 6 ++++-
drivers/staging/media/tegra-vde/tegra-vde.c | 6 ++++-
include/linux/dma-buf.h | 23 ++++++++++++++++--
10 files changed, 74 insertions(+), 21 deletions(-)

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index ef480e5fb239..83c92bfd964c 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -532,8 +532,9 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
/**
* dma_buf_attach - Add the device to dma_buf's attachments list; optionally,
* calls attach() of dma_buf_ops to allow device-specific attach functionality
- * @dmabuf: [in] buffer to attach device to.
- * @dev: [in] device to be attached.
+ * @info: [in] holds all the attach related information provided
+ * by the importer. see &struct dma_buf_attach_info
+ * for further details.
*
* Returns struct dma_buf_attachment pointer for this attachment. Attachments
* must be cleaned up by calling dma_buf_detach().
@@ -547,20 +548,20 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
* accessible to @dev, and cannot be moved to a more suitable place. This is
* indicated with the error code -EBUSY.
*/
-struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
- struct device *dev)
+struct dma_buf_attachment *dma_buf_attach(const struct dma_buf_attach_info *info)
{
+ struct dma_buf *dmabuf = info->dmabuf;
struct dma_buf_attachment *attach;
int ret;

- if (WARN_ON(!dmabuf || !dev))
+ if (WARN_ON(!dmabuf || !info->dev))
return ERR_PTR(-EINVAL);

attach = kzalloc(sizeof(*attach), GFP_KERNEL);
if (!attach)
return ERR_PTR(-ENOMEM);

- attach->dev = dev;
+ attach->dev = info->dev;
attach->dmabuf = dmabuf;

mutex_lock(&dmabuf->lock);
@@ -688,9 +689,9 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
if (attach->sgt)
return attach->sgt;

- sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
- if (!sg_table)
- sg_table = ERR_PTR(-ENOMEM);
+ reservation_object_lock(attach->dmabuf->resv, NULL);
+ sg_table = dma_buf_map_attachment_locked(attach, direction);
+ reservation_object_unlock(attach->dmabuf->resv);

return sg_table;
}
@@ -744,8 +745,9 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
if (attach->sgt == sg_table)
return;

- attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
- direction);
+ reservation_object_lock(attach->dmabuf->resv, NULL);
+ dma_buf_unmap_attachment_locked(attach, sg_table, direction);
+ reservation_object_unlock(attach->dmabuf->resv);
}
EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);

diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index 642d0e70d0f8..19c47821032f 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -501,6 +501,10 @@ armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj,
struct drm_gem_object *
armada_gem_prime_import(struct drm_device *dev, struct dma_buf *buf)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev->dev,
+ .dmabuf = buf
+ };
struct dma_buf_attachment *attach;
struct armada_gem_object *dobj;

@@ -516,7 +520,7 @@ armada_gem_prime_import(struct drm_device *dev, struct dma_buf *buf)
}
}

- attach = dma_buf_attach(buf, dev->dev);
+ attach = dma_buf_attach(&attach_info);
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 231e3f6d5f41..1fadf5d5ed33 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -709,6 +709,10 @@ struct drm_gem_object *drm_gem_prime_import_dev(struct drm_device *dev,
struct dma_buf *dma_buf,
struct device *attach_dev)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = attach_dev,
+ .dmabuf = dma_buf
+ };
struct dma_buf_attachment *attach;
struct sg_table *sgt;
struct drm_gem_object *obj;
@@ -729,7 +733,7 @@ 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(&attach_info);
if (IS_ERR(attach))
return ERR_CAST(attach);

diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 82e2ca17a441..aa7f685bd6ca 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -277,6 +277,10 @@ static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev->dev,
+ .dmabuf = dma_buf
+ };
struct dma_buf_attachment *attach;
struct drm_i915_gem_object *obj;
int ret;
@@ -295,7 +299,7 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
}

/* need to attach */
- attach = dma_buf_attach(dma_buf, dev->dev);
+ attach = dma_buf_attach(&attach_info);
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 4f80100ff5f3..8e6b6c879add 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -332,6 +332,10 @@ struct tegra_bo *tegra_bo_create_with_handle(struct drm_file *file,
static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
struct dma_buf *buf)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = drm->dev,
+ .dmabuf = buf
+ };
struct tegra_drm *tegra = drm->dev_private;
struct dma_buf_attachment *attach;
struct tegra_bo *bo;
@@ -341,7 +345,7 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
if (IS_ERR(bo))
return bo;

- attach = dma_buf_attach(buf, drm->dev);
+ attach = dma_buf_attach(&attach_info);
if (IS_ERR(attach)) {
err = PTR_ERR(attach);
goto free;
diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c
index 556f62662aa9..86b928f9742f 100644
--- a/drivers/gpu/drm/udl/udl_dmabuf.c
+++ b/drivers/gpu/drm/udl/udl_dmabuf.c
@@ -226,6 +226,10 @@ static int udl_prime_create(struct drm_device *dev,
struct drm_gem_object *udl_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev->dev,
+ .dmabuf = dma_buf
+ };
struct dma_buf_attachment *attach;
struct sg_table *sg;
struct udl_gem_object *uobj;
@@ -233,7 +237,7 @@ struct drm_gem_object *udl_gem_prime_import(struct drm_device *dev,

/* need to attach */
get_device(dev->dev);
- attach = dma_buf_attach(dma_buf, dev->dev);
+ attach = dma_buf_attach(&attach_info);
if (IS_ERR(attach)) {
put_device(dev->dev);
return ERR_CAST(attach);
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index aff0ab7bf83d..1f2687b5eb0e 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -676,6 +676,10 @@ static void vb2_dc_detach_dmabuf(void *mem_priv)
static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
unsigned long size, enum dma_data_direction dma_dir)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev,
+ .dmabuf = dbuf
+ };
struct vb2_dc_buf *buf;
struct dma_buf_attachment *dba;

@@ -691,7 +695,7 @@ static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,

buf->dev = dev;
/* create attachment for the dmabuf with the user device */
- dba = dma_buf_attach(dbuf, buf->dev);
+ dba = dma_buf_attach(&attach_info);
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 015e737095cd..cbd626d2393a 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -608,6 +608,10 @@ static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
unsigned long size, enum dma_data_direction dma_dir)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev,
+ .dmabuf = dbuf
+ };
struct vb2_dma_sg_buf *buf;
struct dma_buf_attachment *dba;

@@ -623,7 +627,7 @@ static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,

buf->dev = dev;
/* create attachment for the dmabuf with the user device */
- dba = dma_buf_attach(dbuf, buf->dev);
+ dba = dma_buf_attach(&attach_info);
if (IS_ERR(dba)) {
pr_err("failed to attach dmabuf\n");
kfree(buf);
diff --git a/drivers/staging/media/tegra-vde/tegra-vde.c b/drivers/staging/media/tegra-vde/tegra-vde.c
index aa6c6bba961e..5a10c1facc27 100644
--- a/drivers/staging/media/tegra-vde/tegra-vde.c
+++ b/drivers/staging/media/tegra-vde/tegra-vde.c
@@ -568,6 +568,10 @@ static int tegra_vde_attach_dmabuf(struct device *dev,
size_t *size,
enum dma_data_direction dma_dir)
{
+ struct dma_buf_attach_info attach_info = {
+ .dev = dev,
+ .dmabuf = dmabuf
+ };
struct dma_buf_attachment *attachment;
struct dma_buf *dmabuf;
struct sg_table *sgt;
@@ -591,7 +595,7 @@ static int tegra_vde_attach_dmabuf(struct device *dev,
return -EINVAL;
}

- attachment = dma_buf_attach(dmabuf, dev);
+ attachment = dma_buf_attach(&attach_info);
if (IS_ERR(attachment)) {
dev_err(dev, "Failed to attach dmabuf\n");
err = PTR_ERR(attachment);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 18a78be53541..7e23758db3a4 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -128,6 +128,9 @@ struct dma_buf_ops {
* any other kind of sharing that the exporter might wish to make
* available to buffer-users.
*
+ * This is always called with the dmabuf->resv object locked when
+ * no_sgt_cache is true.
+ *
* Returns:
*
* A &sg_table scatter list of or the backing storage of the DMA buffer,
@@ -148,6 +151,9 @@ struct dma_buf_ops {
* It should also unpin the backing storage if this is the last mapping
* of the DMA buffer, it the exporter supports backing storage
* migration.
+ *
+ * This is always called with the dmabuf->resv object locked when
+ * no_sgt_cache is true.
*/
void (*unmap_dma_buf)(struct dma_buf_attachment *,
struct sg_table *,
@@ -370,6 +376,19 @@ struct dma_buf_export_info {
struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
.owner = THIS_MODULE }

+/**
+ * struct dma_buf_attach_info - holds information needed to attach to a dma_buf
+ * @dmabuf: the exported dma_buf
+ * @dev: the device which wants to import the attachment
+ *
+ * This structure holds the information required to attach to a buffer. Used
+ * with dma_buf_attach() only.
+ */
+struct dma_buf_attach_info {
+ struct dma_buf *dmabuf;
+ struct device *dev;
+};
+
/**
* get_dma_buf - convenience wrapper for get_file.
* @dmabuf: [in] pointer to dma_buf
@@ -384,8 +403,8 @@ static inline void get_dma_buf(struct dma_buf *dmabuf)
get_file(dmabuf->file);
}

-struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
- struct device *dev);
+struct dma_buf_attachment *
+dma_buf_attach(const struct dma_buf_attach_info *info);
void dma_buf_detach(struct dma_buf *dmabuf,
struct dma_buf_attachment *dmabuf_attach);

--
2.17.1
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