From: Alexei Starovoitov ast@kernel.org
commit 05ae68656a8e9d9386ce4243fe992122fd29bb51 upstream.
Factor out inner body of alloc_bulk into separate helper. No functional changes.
Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Hou Tao houtao1@huawei.com Link: https://lore.kernel.org/bpf/20230706033447.54696-5-alexei.starovoitov@gmail.... Signed-off-by: Alexey Nepomnyashih sdl@nppct.ru --- kernel/bpf/memalloc.c | 46 ++++++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 20 deletions(-)
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 0cd863839557..0f45ea4259cb 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -154,11 +154,35 @@ static struct mem_cgroup *get_memcg(const struct bpf_mem_cache *c) #endif }
+static void add_obj_to_free_list(struct bpf_mem_cache *c, void *obj) +{ + unsigned long flags; + + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + /* In RT irq_work runs in per-cpu kthread, so disable + * interrupts to avoid preemption and interrupts and + * reduce the chance of bpf prog executing on this cpu + * when active counter is busy. + */ + local_irq_save(flags); + /* alloc_bulk runs from irq_work which will not preempt a bpf + * program that does unit_alloc/unit_free since IRQs are + * disabled there. There is no race to increment 'active' + * counter. It protects free_llist from corruption in case NMI + * bpf prog preempted this loop. + */ + WARN_ON_ONCE(local_inc_return(&c->active) != 1); + __llist_add(obj, &c->free_llist); + c->free_cnt++; + local_dec(&c->active); + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_restore(flags); +} + /* Mostly runs from irq_work except __init phase. */ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node) { struct mem_cgroup *memcg = NULL, *old_memcg; - unsigned long flags; void *obj; int i;
@@ -188,25 +212,7 @@ static void alloc_bulk(struct bpf_mem_cache *c, int cnt, int node) if (!obj) break; } - if (IS_ENABLED(CONFIG_PREEMPT_RT)) - /* In RT irq_work runs in per-cpu kthread, so disable - * interrupts to avoid preemption and interrupts and - * reduce the chance of bpf prog executing on this cpu - * when active counter is busy. - */ - local_irq_save(flags); - /* alloc_bulk runs from irq_work which will not preempt a bpf - * program that does unit_alloc/unit_free since IRQs are - * disabled there. There is no race to increment 'active' - * counter. It protects free_llist from corruption in case NMI - * bpf prog preempted this loop. - */ - WARN_ON_ONCE(local_inc_return(&c->active) != 1); - __llist_add(obj, &c->free_llist); - c->free_cnt++; - local_dec(&c->active); - if (IS_ENABLED(CONFIG_PREEMPT_RT)) - local_irq_restore(flags); + add_obj_to_free_list(c, obj); } set_active_memcg(old_memcg); mem_cgroup_put(memcg);