[PATCH 01/10] drm/gem: Test for imported GEM buffers with helper

[Thomas Zimmermann]

Am 28.02.25 um 17:04 schrieb Anusha Srivatsa:
>
>
> On Wed, Feb 26, 2025 at 12:28 PM Thomas Zimmermann 
> <tzimmermann at suse.de> 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 at suse.de>
>     ---
>      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 at redhat.com>

Thanks for reviewing.

>      #ifdef CONFIG_LOCKDEP
>      /**
>       * drm_gem_gpuva_set_lock() - Set the lock protecting accesses to
>     the gpuva list.
>     -- 
>     2.48.1
>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)