Re: [PATCH v5 05/11] drm/gpuvm: Add a flags field to drm_gpuva_op_map

["Danilo Krummrich" <dakr@kernel.org>]

On Fri Mar 13, 2026 at 4:09 PM CET, Adrián Larumbe wrote:
> From: Asahi Lina <lina+kernel@asahilina.net>
>
> drm_gpuva objects have a flags field. Currently, this can be managed by
> drivers out-of-band, without any special handling in drm_gpuvm.
>
> To be able to introduce flags that do affect the logic in the drm_gpuvm
> core, we need to plumb it through the map calls. This will allow the
> core to check the flags on map and alter the merge/split logic depending
> on the requested flags and the flags of the existing drm_gpuva ranges
> that are being split.
>
> Signed-off-by: Asahi Lina <lina+kernel@asahilina.net>
> Signed-off-by: Caterina Shablia <caterina.shablia@collabora.com>

Missing Signed-off-by.

> ---
>  drivers/gpu/drm/drm_gpuvm.c | 14 ++++++++++++--
>  include/drm/drm_gpuvm.h     | 18 ++++++++++++++++++
>  2 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c
> index 4af7b71abcb4..0d9c821d1b34 100644
> --- a/drivers/gpu/drm/drm_gpuvm.c
> +++ b/drivers/gpu/drm/drm_gpuvm.c
> @@ -2386,6 +2386,7 @@ static bool can_merge(struct drm_gpuvm *gpuvm, const struct drm_gpuva *va,
>  		.va.range = va->va.range,
>  		.gem.offset = va->gem.offset,
>  		.gem.obj = va->gem.obj,
> +		.flags = va->flags,
>  	};
>  	const struct drm_gpuva_op_map *a = new_map, *b = &existing_map;
>  
> @@ -2395,6 +2396,10 @@ static bool can_merge(struct drm_gpuvm *gpuvm, const struct drm_gpuva *va,
>  	if (a->gem.obj != b->gem.obj || !a->gem.obj)
>  		return false;
>  
> +	/* For two VAs to be merged, their flags must be compatible */
> +	if ((a->flags & VA_MERGE_MUST_MATCH_FLAGS) != (b->flags & VA_MERGE_MUST_MATCH_FLAGS))
> +		return false;

This has nothing to do with this patch, the commit message only talks about
adding flags to struct drm_gpuva_op_map.

Please create a new patch for further changes, v4 of this was fine as is.

> +
>  	/* Order VAs for the rest of the checks. */
>  	if (a->va.addr > b->va.addr)
>  		swap(a, b);
> @@ -2459,6 +2464,7 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
>  					.va.range = range - req_range,
>  					.gem.obj = obj,
>  					.gem.offset = offset + req_range,
> +					.flags = va->flags,
>  				};
>  				struct drm_gpuva_op_unmap u = {
>  					.va = va,
> @@ -2480,6 +2486,7 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
>  				.va.range = ls_range,
>  				.gem.obj = obj,
>  				.gem.offset = offset,
> +				.flags = va->flags,
>  			};
>  			struct drm_gpuva_op_unmap u = { .va = va };
>  
> @@ -2519,8 +2526,8 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
>  					.va.addr = req_end,
>  					.va.range = end - req_end,
>  					.gem.obj = obj,
> -					.gem.offset = offset + ls_range +
> -						      req_range,
> +					.gem.offset = offset + ls_range + req_range,

Spurious change.

> +					.flags = va->flags,
>  				};
>  
>  				ret = op_remap_cb(ops, priv, &p, &n, &u);
> @@ -2554,6 +2561,7 @@ __drm_gpuvm_sm_map(struct drm_gpuvm *gpuvm,
>  					.va.range = end - req_end,
>  					.gem.obj = obj,
>  					.gem.offset = offset + req_end - addr,
> +					.flags = va->flags,
>  				};
>  				struct drm_gpuva_op_unmap u = {
>  					.va = va,
> @@ -2605,6 +2613,7 @@ __drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm,
>  			prev.va.range = req_addr - addr;
>  			prev.gem.obj = obj;
>  			prev.gem.offset = offset;
> +			prev.flags = va->flags;
>  
>  			prev_split = true;
>  		}
> @@ -2614,6 +2623,7 @@ __drm_gpuvm_sm_unmap(struct drm_gpuvm *gpuvm,
>  			next.va.range = end - req_end;
>  			next.gem.obj = obj;
>  			next.gem.offset = offset + (req_end - addr);
> +			next.flags = va->flags;
>  
>  			next_split = true;
>  		}
> diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h
> index 6a6e64cd2cce..5bf37deb282d 100644
> --- a/include/drm/drm_gpuvm.h
> +++ b/include/drm/drm_gpuvm.h
> @@ -63,6 +63,8 @@ enum drm_gpuva_flags {
>  	DRM_GPUVA_USERBITS = (1 << 2),
>  };
>  
> +#define VA_MERGE_MUST_MATCH_FLAGS (DRM_GPUVA_SPARSE)

Please drop this indirection if the only criteria is that both must be sparse.

> +
>  /**
>   * struct drm_gpuva - structure to track a GPU VA mapping
>   *
> @@ -886,6 +888,11 @@ struct drm_gpuva_op_map {
>  		 */
>  		struct drm_gem_object *obj;
>  	} gem;
> +
> +	/**
> +	 * @flags: requested flags for the &drm_gpuva for this mapping
> +	 */
> +	enum drm_gpuva_flags flags;
>  };
>  
>  /**
> @@ -1124,6 +1131,7 @@ void drm_gpuva_ops_free(struct drm_gpuvm *gpuvm,
>  static inline void drm_gpuva_init_from_op(struct drm_gpuva *va,
>  					  const struct drm_gpuva_op_map *op)
>  {
> +	va->flags = op->flags;
>  	va->va.addr = op->va.addr;
>  	va->va.range = op->va.range;
>  	va->gem.obj = op->gem.obj;
> @@ -1249,6 +1257,16 @@ struct drm_gpuvm_ops {
>  	 * used.
>  	 */
>  	int (*sm_step_unmap)(struct drm_gpuva_op *op, void *priv);
> +
> +	/**
> +	 * @sm_can_merge_flags: called during &drm_gpuvm_sm_map
> +	 *
> +	 * This callback is called to determine whether two va ranges can be merged,
> +	 * based on their flags.
> +	 *
> +	 * If NULL, va ranges can only be merged if their flags are equal.
> +	 */
> +	bool (*sm_can_merge_flags)(enum drm_gpuva_flags a, enum drm_gpuva_flags b);

Again, this has nothing to do with this commit, please add a separate patch for
this with a proper commit message explaining the motivation.

Also, this callback appears to be unused and seems to contradict the static
check for compatible merge flags in the hunk above.