From 394e40a29788820c9c0526b1c3497c9e0ec2a126 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 2 Aug 2018 14:27:21 -0700 Subject: [PATCH] bpf: extend bpf_prog_array to store pointers to the cgroup storage This patch converts bpf_prog_array from an array of prog pointers to the array of struct bpf_prog_array_item elements. This allows to save a cgroup storage pointer for each bpf program efficiently attached to a cgroup. Signed-off-by: Roman Gushchin Cc: Alexei Starovoitov Cc: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Daniel Borkmann --- drivers/media/rc/bpf-lirc.c | 10 +++-- include/linux/bpf.h | 19 +++++++--- kernel/bpf/cgroup.c | 21 +++++----- kernel/bpf/core.c | 76 +++++++++++++++++++------------------ 4 files changed, 70 insertions(+), 56 deletions(-) diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index fcfab6635f9c..8c26df9b96c1 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -195,14 +195,16 @@ void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) */ void lirc_bpf_free(struct rc_dev *rcdev) { - struct bpf_prog **progs; + struct bpf_prog_array_item *item; if (!rcdev->raw->progs) return; - progs = rcu_dereference(rcdev->raw->progs)->progs; - while (*progs) - bpf_prog_put(*progs++); + item = rcu_dereference(rcdev->raw->progs)->items; + while (item->prog) { + bpf_prog_put(item->prog); + item++; + } bpf_prog_array_free(rcdev->raw->progs); } diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 9d1e4727495e..16be67888c30 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -349,9 +349,14 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr, * The 'struct bpf_prog_array *' should only be replaced with xchg() * since other cpus are walking the array of pointers in parallel. */ +struct bpf_prog_array_item { + struct bpf_prog *prog; + struct bpf_cgroup_storage *cgroup_storage; +}; + struct bpf_prog_array { struct rcu_head rcu; - struct bpf_prog *progs[0]; + struct bpf_prog_array_item items[0]; }; struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags); @@ -372,7 +377,8 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, #define __BPF_PROG_RUN_ARRAY(array, ctx, func, check_non_null) \ ({ \ - struct bpf_prog **_prog, *__prog; \ + struct bpf_prog_array_item *_item; \ + struct bpf_prog *_prog; \ struct bpf_prog_array *_array; \ u32 _ret = 1; \ preempt_disable(); \ @@ -380,10 +386,11 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, _array = rcu_dereference(array); \ if (unlikely(check_non_null && !_array))\ goto _out; \ - _prog = _array->progs; \ - while ((__prog = READ_ONCE(*_prog))) { \ - _ret &= func(__prog, ctx); \ - _prog++; \ + _item = &_array->items[0]; \ + while ((_prog = READ_ONCE(_item->prog))) { \ + bpf_cgroup_storage_set(_item->cgroup_storage); \ + _ret &= func(_prog, ctx); \ + _item++; \ } \ _out: \ rcu_read_unlock(); \ diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 935274c86bfe..ddfa6cc13e57 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -117,15 +117,18 @@ static int compute_effective_progs(struct cgroup *cgrp, cnt = 0; p = cgrp; do { - if (cnt == 0 || (p->bpf.flags[type] & BPF_F_ALLOW_MULTI)) - list_for_each_entry(pl, - &p->bpf.progs[type], node) { - if (!pl->prog) - continue; - progs->progs[cnt++] = pl->prog; - } - p = cgroup_parent(p); - } while (p); + if (cnt > 0 && !(p->bpf.flags[type] & BPF_F_ALLOW_MULTI)) + continue; + + list_for_each_entry(pl, &p->bpf.progs[type], node) { + if (!pl->prog) + continue; + + progs->items[cnt].prog = pl->prog; + progs->items[cnt].cgroup_storage = pl->storage; + cnt++; + } + } while ((p = cgroup_parent(p))); rcu_assign_pointer(*array, progs); return 0; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 253aa8e79c7b..9abcf25ebf9f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1542,7 +1542,8 @@ struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) { if (prog_cnt) return kzalloc(sizeof(struct bpf_prog_array) + - sizeof(struct bpf_prog *) * (prog_cnt + 1), + sizeof(struct bpf_prog_array_item) * + (prog_cnt + 1), flags); return &empty_prog_array.hdr; @@ -1556,43 +1557,45 @@ void bpf_prog_array_free(struct bpf_prog_array __rcu *progs) kfree_rcu(progs, rcu); } -int bpf_prog_array_length(struct bpf_prog_array __rcu *progs) +int bpf_prog_array_length(struct bpf_prog_array __rcu *array) { - struct bpf_prog **prog; + struct bpf_prog_array_item *item; u32 cnt = 0; rcu_read_lock(); - prog = rcu_dereference(progs)->progs; - for (; *prog; prog++) - if (*prog != &dummy_bpf_prog.prog) + item = rcu_dereference(array)->items; + for (; item->prog; item++) + if (item->prog != &dummy_bpf_prog.prog) cnt++; rcu_read_unlock(); return cnt; } -static bool bpf_prog_array_copy_core(struct bpf_prog **prog, + +static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array, u32 *prog_ids, u32 request_cnt) { + struct bpf_prog_array_item *item; int i = 0; - for (; *prog; prog++) { - if (*prog == &dummy_bpf_prog.prog) + item = rcu_dereference(array)->items; + for (; item->prog; item++) { + if (item->prog == &dummy_bpf_prog.prog) continue; - prog_ids[i] = (*prog)->aux->id; + prog_ids[i] = item->prog->aux->id; if (++i == request_cnt) { - prog++; + item++; break; } } - return !!(*prog); + return !!(item->prog); } -int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, +int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array, __u32 __user *prog_ids, u32 cnt) { - struct bpf_prog **prog; unsigned long err = 0; bool nospc; u32 *ids; @@ -1611,8 +1614,7 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, if (!ids) return -ENOMEM; rcu_read_lock(); - prog = rcu_dereference(progs)->progs; - nospc = bpf_prog_array_copy_core(prog, ids, cnt); + nospc = bpf_prog_array_copy_core(array, ids, cnt); rcu_read_unlock(); err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); kfree(ids); @@ -1623,14 +1625,14 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, return 0; } -void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs, +void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array, struct bpf_prog *old_prog) { - struct bpf_prog **prog = progs->progs; + struct bpf_prog_array_item *item = array->items; - for (; *prog; prog++) - if (*prog == old_prog) { - WRITE_ONCE(*prog, &dummy_bpf_prog.prog); + for (; item->prog; item++) + if (item->prog == old_prog) { + WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); break; } } @@ -1641,7 +1643,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, struct bpf_prog_array **new_array) { int new_prog_cnt, carry_prog_cnt = 0; - struct bpf_prog **existing_prog; + struct bpf_prog_array_item *existing; struct bpf_prog_array *array; bool found_exclude = false; int new_prog_idx = 0; @@ -1650,15 +1652,15 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, * the new array. */ if (old_array) { - existing_prog = old_array->progs; - for (; *existing_prog; existing_prog++) { - if (*existing_prog == exclude_prog) { + existing = old_array->items; + for (; existing->prog; existing++) { + if (existing->prog == exclude_prog) { found_exclude = true; continue; } - if (*existing_prog != &dummy_bpf_prog.prog) + if (existing->prog != &dummy_bpf_prog.prog) carry_prog_cnt++; - if (*existing_prog == include_prog) + if (existing->prog == include_prog) return -EEXIST; } } @@ -1684,15 +1686,17 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, /* Fill in the new prog array */ if (carry_prog_cnt) { - existing_prog = old_array->progs; - for (; *existing_prog; existing_prog++) - if (*existing_prog != exclude_prog && - *existing_prog != &dummy_bpf_prog.prog) - array->progs[new_prog_idx++] = *existing_prog; + existing = old_array->items; + for (; existing->prog; existing++) + if (existing->prog != exclude_prog && + existing->prog != &dummy_bpf_prog.prog) { + array->items[new_prog_idx++].prog = + existing->prog; + } } if (include_prog) - array->progs[new_prog_idx++] = include_prog; - array->progs[new_prog_idx] = NULL; + array->items[new_prog_idx++].prog = include_prog; + array->items[new_prog_idx].prog = NULL; *new_array = array; return 0; } @@ -1701,7 +1705,6 @@ int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, u32 *prog_ids, u32 request_cnt, u32 *prog_cnt) { - struct bpf_prog **prog; u32 cnt = 0; if (array) @@ -1714,8 +1717,7 @@ int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, return 0; /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ - prog = rcu_dereference_check(array, 1)->progs; - return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC + return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC : 0; } -- 2.45.2