On Wed, Feb 26, 2025 at 12:28 PM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
Add drm_gem_is_imported() that tests if a GEM object's buffer has
been imported. Update the GEM code accordingly.
GEM code usually tests for imports if import_attach has been set
in struct drm_gem_object. But attaching a dma-buf on import requires
a DMA-capable importer device, which is not the case for many serial
busses like USB or I2C. The new helper tests if a GEM object's dma-buf
has been created from the GEM object.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_gem.c | 4 ++--
include/drm/drm_gem.h | 14 ++++++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index ee811764c3df..c6240bab3fa5 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -348,7 +348,7 @@ int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
return -ENOENT;
/* Don't allow imported objects to be mapped */
- if (obj->import_attach) {
+ if (drm_gem_is_imported(obj)) {
ret = -EINVAL;
goto out;
}
@@ -1178,7 +1178,7 @@ void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
drm_vma_node_start(&obj->vma_node));
drm_printf_indent(p, indent, "size=%zu\n", obj->size);
drm_printf_indent(p, indent, "imported=%s\n",
- str_yes_no(obj->import_attach));
+ str_yes_no(drm_gem_is_imported(obj)));
if (obj->funcs->print_info)
obj->funcs->print_info(p, indent, obj);
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index fdae947682cd..2bf893eabb4b 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -35,6 +35,7 @@
*/
#include <linux/kref.h>
+#include <linux/dma-buf.h>
#include <linux/dma-resv.h>
#include <linux/list.h>
#include <linux/mutex.h>
@@ -575,6 +576,19 @@ static inline bool drm_gem_object_is_shared_for_memory_stats(struct drm_gem_obje
return (obj->handle_count > 1) || obj->dma_buf;
}
+/**
+ * drm_gem_is_imported() - Tests if GEM object's buffer has been imported
+ * @obj: the GEM object
+ *
+ * Returns:
+ * True if the GEM object's buffer has been imported, false otherwise
+ */
+static inline bool drm_gem_is_imported(const struct drm_gem_object *obj)
+{
+ /* The dma-buf's priv field points to the original GEM object. */
+ return obj->dma_buf && (obj->dma_buf->priv != obj);
+}
+
Looks good to me.
Reviewed-by: Anusha Srivatsa <asrivats@xxxxxxxxxx>
#ifdef CONFIG_LOCKDEP
/**
* drm_gem_gpuva_set_lock() - Set the lock protecting accesses to the gpuva list.
--
2.48.1
