diff options
| -rw-r--r-- | include/linux/bpf_local_storage.h | 30 | ||||
| -rw-r--r-- | kernel/bpf/bpf_local_storage.c | 52 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/task_local_storage.c | 6 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c | 26 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/task_ls_recursion.c | 17 |
5 files changed, 41 insertions, 90 deletions
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index 173ec7f43ed1..dcddb0aef7d8 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -129,10 +129,36 @@ bpf_local_storage_map_alloc(union bpf_attr *attr, struct bpf_local_storage_cache *cache, bool bpf_ma); -struct bpf_local_storage_data * +void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + struct bpf_local_storage_elem *selem); +/* If cacheit_lockit is false, this lookup function is lockless */ +static inline struct bpf_local_storage_data * bpf_local_storage_lookup(struct bpf_local_storage *local_storage, struct bpf_local_storage_map *smap, - bool cacheit_lockit); + bool cacheit_lockit) +{ + struct bpf_local_storage_data *sdata; + struct bpf_local_storage_elem *selem; + + /* Fast path (cache hit) */ + sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx], + bpf_rcu_lock_held()); + if (sdata && rcu_access_pointer(sdata->smap) == smap) + return sdata; + + /* Slow path (cache miss) */ + hlist_for_each_entry_rcu(selem, &local_storage->list, snode, + rcu_read_lock_trace_held()) + if (rcu_access_pointer(SDATA(selem)->smap) == smap) + break; + + if (!selem) + return NULL; + if (cacheit_lockit) + __bpf_local_storage_insert_cache(local_storage, smap, selem); + return SDATA(selem); +} void bpf_local_storage_destroy(struct bpf_local_storage *local_storage); diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 146824cc9689..bdea1a459153 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -414,47 +414,21 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) bpf_selem_unlink_storage(selem, reuse_now); } -/* If cacheit_lockit is false, this lookup function is lockless */ -struct bpf_local_storage_data * -bpf_local_storage_lookup(struct bpf_local_storage *local_storage, - struct bpf_local_storage_map *smap, - bool cacheit_lockit) +void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage, + struct bpf_local_storage_map *smap, + struct bpf_local_storage_elem *selem) { - struct bpf_local_storage_data *sdata; - struct bpf_local_storage_elem *selem; - - /* Fast path (cache hit) */ - sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx], - bpf_rcu_lock_held()); - if (sdata && rcu_access_pointer(sdata->smap) == smap) - return sdata; - - /* Slow path (cache miss) */ - hlist_for_each_entry_rcu(selem, &local_storage->list, snode, - rcu_read_lock_trace_held()) - if (rcu_access_pointer(SDATA(selem)->smap) == smap) - break; - - if (!selem) - return NULL; - - sdata = SDATA(selem); - if (cacheit_lockit) { - unsigned long flags; - - /* spinlock is needed to avoid racing with the - * parallel delete. Otherwise, publishing an already - * deleted sdata to the cache will become a use-after-free - * problem in the next bpf_local_storage_lookup(). - */ - raw_spin_lock_irqsave(&local_storage->lock, flags); - if (selem_linked_to_storage(selem)) - rcu_assign_pointer(local_storage->cache[smap->cache_idx], - sdata); - raw_spin_unlock_irqrestore(&local_storage->lock, flags); - } + unsigned long flags; - return sdata; + /* spinlock is needed to avoid racing with the + * parallel delete. Otherwise, publishing an already + * deleted sdata to the cache will become a use-after-free + * problem in the next bpf_local_storage_lookup(). + */ + raw_spin_lock_irqsave(&local_storage->lock, flags); + if (selem_linked_to_storage(selem)) + rcu_assign_pointer(local_storage->cache[smap->cache_idx], SDATA(selem)); + raw_spin_unlock_irqrestore(&local_storage->lock, flags); } static int check_flags(const struct bpf_local_storage_data *old_sdata, diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c index ea8537c54413..c33c05161a9e 100644 --- a/tools/testing/selftests/bpf/prog_tests/task_local_storage.c +++ b/tools/testing/selftests/bpf/prog_tests/task_local_storage.c @@ -117,12 +117,6 @@ static void test_recursion(void) ASSERT_OK(err, "lookup map_b"); ASSERT_EQ(value, 100, "map_b value"); - prog_fd = bpf_program__fd(skel->progs.on_lookup); - memset(&info, 0, sizeof(info)); - err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len); - ASSERT_OK(err, "get prog info"); - ASSERT_GT(info.recursion_misses, 0, "on_lookup prog recursion"); - prog_fd = bpf_program__fd(skel->progs.on_update); memset(&info, 0, sizeof(info)); err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len); diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c index 610c2427fd93..3500e4b69ebe 100644 --- a/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c +++ b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c @@ -27,32 +27,6 @@ bool is_cgroup1 = 0; struct cgroup *bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id) __ksym; void bpf_cgroup_release(struct cgroup *cgrp) __ksym; -static void __on_lookup(struct cgroup *cgrp) -{ - bpf_cgrp_storage_delete(&map_a, cgrp); - bpf_cgrp_storage_delete(&map_b, cgrp); -} - -SEC("fentry/bpf_local_storage_lookup") -int BPF_PROG(on_lookup) -{ - struct task_struct *task = bpf_get_current_task_btf(); - struct cgroup *cgrp; - - if (is_cgroup1) { - cgrp = bpf_task_get_cgroup1(task, target_hid); - if (!cgrp) - return 0; - - __on_lookup(cgrp); - bpf_cgroup_release(cgrp); - return 0; - } - - __on_lookup(task->cgroups->dfl_cgrp); - return 0; -} - static void __on_update(struct cgroup *cgrp) { long *ptr; diff --git a/tools/testing/selftests/bpf/progs/task_ls_recursion.c b/tools/testing/selftests/bpf/progs/task_ls_recursion.c index 4542dc683b44..f1853c38aada 100644 --- a/tools/testing/selftests/bpf/progs/task_ls_recursion.c +++ b/tools/testing/selftests/bpf/progs/task_ls_recursion.c @@ -27,23 +27,6 @@ struct { __type(value, long); } map_b SEC(".maps"); -SEC("fentry/bpf_local_storage_lookup") -int BPF_PROG(on_lookup) -{ - struct task_struct *task = bpf_get_current_task_btf(); - - if (!test_pid || task->pid != test_pid) - return 0; - - /* The bpf_task_storage_delete will call - * bpf_local_storage_lookup. The prog->active will - * stop the recursion. - */ - bpf_task_storage_delete(&map_a, task); - bpf_task_storage_delete(&map_b, task); - return 0; -} - SEC("fentry/bpf_local_storage_update") int BPF_PROG(on_update) { |