sched: Simplify the free path some

If we check the root_domain reference count we can see if its been
used or not, use this observation to simplify some of the return
paths.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110407122942.298339503@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 6520484..72c194c 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7023,7 +7023,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
 
        switch (what) {
        case sa_rootdomain:
-               free_rootdomain(&d->rd->rcu); /* fall through */
+               if (!atomic_read(&d->rd->refcount))
+                       free_rootdomain(&d->rd->rcu); /* fall through */
        case sa_sd:
                free_percpu(d->sd); /* fall through */
        case sa_sd_storage:
@@ -7208,7 +7209,7 @@ static int build_sched_domains(const struct cpumask *cpu_map,
        enum s_alloc alloc_state = sa_none;
        struct sched_domain *sd;
        struct s_data d;
-       int i;
+       int i, ret = -ENOMEM;
 
        alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
        if (alloc_state != sa_rootdomain)
@@ -7261,12 +7262,10 @@ static int build_sched_domains(const struct cpumask *cpu_map,
        }
        rcu_read_unlock();
 
-       __free_domain_allocs(&d, sa_sd, cpu_map);
-       return 0;
-
+       ret = 0;
 error:
        __free_domain_allocs(&d, alloc_state, cpu_map);
-       return -ENOMEM;
+       return ret;
 }
 
 static cpumask_var_t *doms_cur;        /* current sched domains */