[PATCH] Initialize the obj flags for shmem objects

[Matthew Auld]

On 03/02/2023 11:57, Aravind Iddamsetty wrote:
> Obj flags for shmem objects is not being set correctly.
> 
> Cc: Matthew Auld <matthew.auld at intel.com>
> Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty at intel.com>

Subject should have "drm/i915:" prefix.

This is also a bug fix due to not setting BO_ALLOC_USER (the other flags 
don't seem to matter for shmem), which is quite important, so we need to 
figure out the "Fixes" tag. Maybe mention in the commit message that 
this fixes setting ALLOC_USER which is needed even for shmem.

Looking at the git history, ALLOC_USER looks to be first introduced in 
213d50927763 ("drm/i915/ttm: Introduce a TTM i915 gem object backend"), 
but the users of ALLOC_USER at this stage are only interesting for the 
ttm backend, and that already passes the flags due to using its own 
object_init() vfunc for all normal object types.

So the first real user impacted by this bug appears to be in: 
13d29c823738 ("drm/i915/ehl: unconditionally flush the pages on acquire").

So I think needs:

Fixes: 13d29c823738 ("drm/i915/ehl: unconditionally flush the pages on 
acquire")
Cc: <stable at vger.kernel.org> # v5.15+

With that,
Reviewed-by: Matthew Auld <matthew.auld at intel.com>


> ---
>   drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> index 114443096841..37d1efcd3ca6 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> @@ -596,7 +596,7 @@ static int shmem_object_init(struct intel_memory_region *mem,
>   	mapping_set_gfp_mask(mapping, mask);
>   	GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
>   
> -	i915_gem_object_init(obj, &i915_gem_shmem_ops, &lock_class, 0);
> +	i915_gem_object_init(obj, &i915_gem_shmem_ops, &lock_class, flags);
>   	obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
>   	obj->write_domain = I915_GEM_DOMAIN_CPU;
>   	obj->read_domains = I915_GEM_DOMAIN_CPU;