linux-kernel - Re: [PATCH] Remove custom dumb_map_offset implementation in msm driver

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Message-ID: <CAA8EJpo+38OVfnmyE0zqDkVOss5GfPbR52FuObTxswCbtYtkig@mail.gmail.com>
Date:   Tue, 14 Nov 2023 16:04:22 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Dipam Turkar <dipamt1729@...il.com>
Cc:     robdclark@...il.com, quic_abhinavk@...cinc.com, sean@...rly.run,
        marijn.suijten@...ainline.org, airlied@...il.com, daniel@...ll.ch,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Remove custom dumb_map_offset implementation in msm driver

On Tue, 14 Nov 2023 at 15:28, Dipam Turkar <dipamt1729@...il.com> wrote:
>
> Make msm use drm_gem_create_map_offset() instead of its custom
> implementation for associating GEM object with a fake offset. Since,
> we already have this generic implementation, we don't need the custom
> implementation and it is better to standardize the code for GEM based drivers.
>
> Signed-off-by: Dipam Turkar <dipamt1729@...il.com>
> ---
>  drivers/gpu/drm/msm/msm_drv.c |  2 +-
>  drivers/gpu/drm/msm/msm_gem.c | 21 ---------------------
>  drivers/gpu/drm/msm/msm_gem.h |  2 --
>  3 files changed, 1 insertion(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
> index a428951ee539..86a15992c717 100644
> --- a/drivers/gpu/drm/msm/msm_drv.c
> +++ b/drivers/gpu/drm/msm/msm_drv.c
> @@ -1085,7 +1085,7 @@ static const struct drm_driver msm_driver = {
>         .open               = msm_open,
>         .postclose          = msm_postclose,
>         .dumb_create        = msm_gem_dumb_create,
> -       .dumb_map_offset    = msm_gem_dumb_map_offset,
> +       .dumb_map_offset    = drm_gem_dumb_map_offset,
>         .gem_prime_import_sg_table = msm_gem_prime_import_sg_table,
>  #ifdef CONFIG_DEBUG_FS
>         .debugfs_init       = msm_debugfs_init,
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index db1e748daa75..489694ef79cb 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -671,27 +671,6 @@ int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
>                         MSM_BO_SCANOUT | MSM_BO_WC, &args->handle, "dumb");
>  }
>
> -int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
> -               uint32_t handle, uint64_t *offset)
> -{
> -       struct drm_gem_object *obj;
> -       int ret = 0;
> -
> -       /* GEM does all our handle to object mapping */
> -       obj = drm_gem_object_lookup(file, handle);
> -       if (obj == NULL) {
> -               ret = -ENOENT;
> -               goto fail;
> -       }
> -
> -       *offset = msm_gem_mmap_offset(obj);

msm_gem_mmap_offset internally has locking around
drm_gem_create_mmap_offset() / drm_vma_node_offset_addr() calls, while
 drm_gem_dumb_map_offset() does not. Thus this patch does more than is
stated in the commit message.

> -
> -       drm_gem_object_put(obj);
> -
> -fail:
> -       return ret;
> -}
> -
>  static void *get_vaddr(struct drm_gem_object *obj, unsigned madv)
>  {
>         struct msm_gem_object *msm_obj = to_msm_bo(obj);
> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
> index 8ddef5443140..dc74a0ef865d 100644
> --- a/drivers/gpu/drm/msm/msm_gem.h
> +++ b/drivers/gpu/drm/msm/msm_gem.h
> @@ -139,8 +139,6 @@ struct page **msm_gem_pin_pages(struct drm_gem_object *obj);
>  void msm_gem_unpin_pages(struct drm_gem_object *obj);
>  int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
>                 struct drm_mode_create_dumb *args);
> -int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
> -               uint32_t handle, uint64_t *offset);
>  void *msm_gem_get_vaddr_locked(struct drm_gem_object *obj);
>  void *msm_gem_get_vaddr(struct drm_gem_object *obj);
>  void *msm_gem_get_vaddr_active(struct drm_gem_object *obj);
> --
> 2.34.1
>


-- 
With best wishes
Dmitry