cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2077665

commit c0f2df4
Author: Tejun Heo <tj@kernel.org>
Date:   Sun, 28 Aug 2022 17:54:15 -1000

    cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG

    fa7e439 ("cgroup: Homogenize cgroup_get_from_id() return value") broken
    build when CONFIG_SHRINKER_DEBUG by trying to return an errno from
    mem_cgroup_get_from_ino() which returns struct mem_cgroup *. Fix by using
    ERR_CAST() instead.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
    Cc: Michal Koutný <mkoutny@suse.com>f
    Fixes: fa7e439 ("cgroup: Homogenize cgroup_get_from_id() return value")

Signed-off-by: Waiman Long <longman@redhat.com>

Author: Waiman-Long

mm/memcontrol.c

@@ -5147,7 +5147,7 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
 
 	cgrp = cgroup_get_from_id(ino);
 	if (IS_ERR(cgrp))
-		return PTR_ERR(cgrp);
+		return ERR_CAST(cgrp);
 
 	css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
 	if (css)