sched: avoid flexible array member inside struct (gcc extension) struct sched_group and struct sched_domain end in 'unsigned long cpumask[]' which Jeff Garzik notes is not legal to place inside another struct. It upsets sparse and clang (LLVM's C front end). Al Viro pointed out that a union is the Right Way to do this. Signed-off-by: Rusty Russell Reported-by: Jeff Garzik Acked-by: Jeff Garzik Acked-by: Al Viro --- kernel/sched.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7756,22 +7756,24 @@ int sched_smt_power_savings = 0, sched_m * FIXME: use cpumask_var_t or dynamic percpu alloc to avoid wasting space * for nr_cpu_ids < CONFIG_NR_CPUS. */ -struct static_sched_group { +union static_sched_group { struct sched_group sg; - DECLARE_BITMAP(cpus, CONFIG_NR_CPUS); -}; - -struct static_sched_domain { + char _sg_and_cpus[sizeof(struct sched_group) + + BITS_TO_LONGS(CONFIG_NR_CPUS) * sizeof(long)]; +}; + +union static_sched_domain { struct sched_domain sd; - DECLARE_BITMAP(span, CONFIG_NR_CPUS); + char _sd_and_cpus[sizeof(struct sched_domain) + + BITS_TO_LONGS(CONFIG_NR_CPUS) * sizeof(long)]; }; /* * SMT sched-domains: */ #ifdef CONFIG_SCHED_SMT -static DEFINE_PER_CPU(struct static_sched_domain, cpu_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_cpus); +static DEFINE_PER_CPU(union static_sched_domain, cpu_domains); +static DEFINE_PER_CPU(union static_sched_group, sched_group_cpus); static int cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map, @@ -7787,8 +7789,8 @@ cpu_to_cpu_group(int cpu, const struct c * multi-core sched-domains: */ #ifdef CONFIG_SCHED_MC -static DEFINE_PER_CPU(struct static_sched_domain, core_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_core); +static DEFINE_PER_CPU(union static_sched_domain, core_domains); +static DEFINE_PER_CPU(union static_sched_group, sched_group_core); #endif /* CONFIG_SCHED_MC */ #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) @@ -7815,8 +7817,8 @@ cpu_to_core_group(int cpu, const struct } #endif -static DEFINE_PER_CPU(struct static_sched_domain, phys_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys); +static DEFINE_PER_CPU(union static_sched_domain, phys_domains); +static DEFINE_PER_CPU(union static_sched_group, sched_group_phys); static int cpu_to_phys_group(int cpu, const struct cpumask *cpu_map, @@ -7843,11 +7845,11 @@ cpu_to_phys_group(int cpu, const struct * groups, so roll our own. Now each node has its own list of groups which * gets dynamically allocated. */ -static DEFINE_PER_CPU(struct static_sched_domain, node_domains); +static DEFINE_PER_CPU(union static_sched_domain, node_domains); static struct sched_group ***sched_group_nodes_bycpu; -static DEFINE_PER_CPU(struct static_sched_domain, allnodes_domains); -static DEFINE_PER_CPU(struct static_sched_group, sched_group_allnodes); +static DEFINE_PER_CPU(union static_sched_domain, allnodes_domains); +static DEFINE_PER_CPU(union static_sched_group, sched_group_allnodes); static int cpu_to_allnodes_group(int cpu, const struct cpumask *cpu_map, struct sched_group **sg,