drm: Use idr_init_base(1) when using id==0 for invalid
Use the new idr_init_base() function to create an IDR that knows id==0 is never allocated as it maps to an invalid identifier. By knowing that id==0 is invalid, the IDR can start from id=1 instead avoiding the issue of having to start each lookup from the zeroth leaf as id==0 is always unused (and thus the tree-of-bitmaps indicate that is the first available). References: 6ce711f2 ("idr: Make 1-based IDRs more efficient") Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Christian Konig <christian.koenig@amd.com> Cc: Dave Airlie <airlied@redhat.com> Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com> Acked-by: Christian König <christian.koenig@amd.com> as well. Link: https://patchwork.freedesktop.org/patch/msgid/20180212145533.30046-1-chris@chris-wilson.co.uk
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