[PATCH 13/34] drm/amdgpu: Convert ctx_handles to XArray

[Matthew Wilcox]

On Mon, Feb 25, 2019 at 05:07:24PM +0100, Christian König wrote:
> > -#define AMDGPU_VM_MAX_NUM_CTX			4096
> > +#define AMDGPU_VM_CTX_LIMIT			XA_LIMIT(0, 4095)
> 
> IIRC we actually use 0 as reserved context value in some places.

That's OK; the ALLOC1 prevents it from using index 0.

You can change it to be XA_LIMIT(1, 4095) if you think that'll be clearer;
it'll be slightly less efficient assembly (a 64-bit mov-immediate instead
of a 32-bit mov-immediate), but it's your driver, so it's up to you.

> > @@ -533,22 +533,18 @@ int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx,
> >   void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr)
> >   {
> >   	mutex_init(&mgr->lock);
> > -	idr_init(&mgr->ctx_handles);
> > +	xa_init_flags(&mgr->ctx_handles, XA_FLAGS_ALLOC1);
> >   }
> >   void amdgpu_ctx_mgr_entity_flush(struct amdgpu_ctx_mgr *mgr)
> >   {