From: Stanislav Fomichev sdf@google.com
[ Upstream commit 00442143a2ab7f1da46fbf4d2a99c85df767d49a ]
This lets us reclaim some space to be used by new cgroup lsm slots.
Before: struct cgroup_bpf { struct bpf_prog_array * effective[23]; /* 0 184 */ /* --- cacheline 2 boundary (128 bytes) was 56 bytes ago --- */ struct list_head progs[23]; /* 184 368 */ /* --- cacheline 8 boundary (512 bytes) was 40 bytes ago --- */ u32 flags[23]; /* 552 92 */
/* XXX 4 bytes hole, try to pack */
/* --- cacheline 10 boundary (640 bytes) was 8 bytes ago --- */ struct list_head storages; /* 648 16 */ struct bpf_prog_array * inactive; /* 664 8 */ struct percpu_ref refcnt; /* 672 16 */ struct work_struct release_work; /* 688 32 */
/* size: 720, cachelines: 12, members: 7 */ /* sum members: 716, holes: 1, sum holes: 4 */ /* last cacheline: 16 bytes */ };
After: struct cgroup_bpf { struct bpf_prog_array * effective[23]; /* 0 184 */ /* --- cacheline 2 boundary (128 bytes) was 56 bytes ago --- */ struct hlist_head progs[23]; /* 184 184 */ /* --- cacheline 5 boundary (320 bytes) was 48 bytes ago --- */ u8 flags[23]; /* 368 23 */
/* XXX 1 byte hole, try to pack */
/* --- cacheline 6 boundary (384 bytes) was 8 bytes ago --- */ struct list_head storages; /* 392 16 */ struct bpf_prog_array * inactive; /* 408 8 */ struct percpu_ref refcnt; /* 416 16 */ struct work_struct release_work; /* 432 72 */
/* size: 504, cachelines: 8, members: 7 */ /* sum members: 503, holes: 1, sum holes: 1 */ /* last cacheline: 56 bytes */ };
Suggested-by: Jakub Sitnicki jakub@cloudflare.com Reviewed-by: Jakub Sitnicki jakub@cloudflare.com Reviewed-by: Martin KaFai Lau kafai@fb.com Signed-off-by: Stanislav Fomichev sdf@google.com Link: https://lore.kernel.org/r/20220628174314.1216643-3-sdf@google.com Signed-off-by: Alexei Starovoitov ast@kernel.org Stable-dep-of: 883743422ced ("bpf: Fix ref_obj_id for dynptr data slices in verifier") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/bpf-cgroup-defs.h | 4 +- include/linux/bpf-cgroup.h | 2 +- kernel/bpf/cgroup.c | 76 +++++++++++++++++++-------------- 3 files changed, 47 insertions(+), 35 deletions(-)
diff --git a/include/linux/bpf-cgroup-defs.h b/include/linux/bpf-cgroup-defs.h index 695d1224a71b..5d268e76d8e6 100644 --- a/include/linux/bpf-cgroup-defs.h +++ b/include/linux/bpf-cgroup-defs.h @@ -47,8 +47,8 @@ struct cgroup_bpf { * have either zero or one element * when BPF_F_ALLOW_MULTI the list can have up to BPF_CGROUP_MAX_PROGS */ - struct list_head progs[MAX_CGROUP_BPF_ATTACH_TYPE]; - u32 flags[MAX_CGROUP_BPF_ATTACH_TYPE]; + struct hlist_head progs[MAX_CGROUP_BPF_ATTACH_TYPE]; + u8 flags[MAX_CGROUP_BPF_ATTACH_TYPE];
/* list of cgroup shared storages */ struct list_head storages; diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 669d96d074ad..6673acfbf2ef 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -95,7 +95,7 @@ struct bpf_cgroup_link { };
struct bpf_prog_list { - struct list_head node; + struct hlist_node node; struct bpf_prog *prog; struct bpf_cgroup_link *link; struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]; diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 34dfa45ef4f3..13526b01f1fd 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -157,11 +157,12 @@ static void cgroup_bpf_release(struct work_struct *work) mutex_lock(&cgroup_mutex);
for (atype = 0; atype < ARRAY_SIZE(cgrp->bpf.progs); atype++) { - struct list_head *progs = &cgrp->bpf.progs[atype]; - struct bpf_prog_list *pl, *pltmp; + struct hlist_head *progs = &cgrp->bpf.progs[atype]; + struct bpf_prog_list *pl; + struct hlist_node *pltmp;
- list_for_each_entry_safe(pl, pltmp, progs, node) { - list_del(&pl->node); + hlist_for_each_entry_safe(pl, pltmp, progs, node) { + hlist_del(&pl->node); if (pl->prog) bpf_prog_put(pl->prog); if (pl->link) @@ -217,12 +218,12 @@ static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl) /* count number of elements in the list. * it's slow but the list cannot be long */ -static u32 prog_list_length(struct list_head *head) +static u32 prog_list_length(struct hlist_head *head) { struct bpf_prog_list *pl; u32 cnt = 0;
- list_for_each_entry(pl, head, node) { + hlist_for_each_entry(pl, head, node) { if (!prog_list_prog(pl)) continue; cnt++; @@ -291,7 +292,7 @@ static int compute_effective_progs(struct cgroup *cgrp, if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI)) continue;
- list_for_each_entry(pl, &p->bpf.progs[atype], node) { + hlist_for_each_entry(pl, &p->bpf.progs[atype], node) { if (!prog_list_prog(pl)) continue;
@@ -342,7 +343,7 @@ int cgroup_bpf_inherit(struct cgroup *cgrp) cgroup_bpf_get(p);
for (i = 0; i < NR; i++) - INIT_LIST_HEAD(&cgrp->bpf.progs[i]); + INIT_HLIST_HEAD(&cgrp->bpf.progs[i]);
INIT_LIST_HEAD(&cgrp->bpf.storages);
@@ -418,7 +419,7 @@ static int update_effective_progs(struct cgroup *cgrp,
#define BPF_CGROUP_MAX_PROGS 64
-static struct bpf_prog_list *find_attach_entry(struct list_head *progs, +static struct bpf_prog_list *find_attach_entry(struct hlist_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, struct bpf_prog *replace_prog, @@ -428,12 +429,12 @@ static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
/* single-attach case */ if (!allow_multi) { - if (list_empty(progs)) + if (hlist_empty(progs)) return NULL; - return list_first_entry(progs, typeof(*pl), node); + return hlist_entry(progs->first, typeof(*pl), node); }
- list_for_each_entry(pl, progs, node) { + hlist_for_each_entry(pl, progs, node) { if (prog && pl->prog == prog && prog != replace_prog) /* disallow attaching the same prog twice */ return ERR_PTR(-EINVAL); @@ -444,7 +445,7 @@ static struct bpf_prog_list *find_attach_entry(struct list_head *progs,
/* direct prog multi-attach w/ replacement case */ if (replace_prog) { - list_for_each_entry(pl, progs, node) { + hlist_for_each_entry(pl, progs, node) { if (pl->prog == replace_prog) /* a match found */ return pl; @@ -480,7 +481,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_cgroup_storage *new_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {}; enum cgroup_bpf_attach_type atype; struct bpf_prog_list *pl; - struct list_head *progs; + struct hlist_head *progs; int err;
if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) || @@ -503,7 +504,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, if (!hierarchy_allows_attach(cgrp, atype)) return -EPERM;
- if (!list_empty(progs) && cgrp->bpf.flags[atype] != saved_flags) + if (!hlist_empty(progs) && cgrp->bpf.flags[atype] != saved_flags) /* Disallow attaching non-overridable on top * of existing overridable in this cgroup. * Disallow attaching multi-prog if overridable or none @@ -525,12 +526,22 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, if (pl) { old_prog = pl->prog; } else { + struct hlist_node *last = NULL; + pl = kmalloc(sizeof(*pl), GFP_KERNEL); if (!pl) { bpf_cgroup_storages_free(new_storage); return -ENOMEM; } - list_add_tail(&pl->node, progs); + if (hlist_empty(progs)) + hlist_add_head(&pl->node, progs); + else + hlist_for_each(last, progs) { + if (last->next) + continue; + hlist_add_behind(&pl->node, last); + break; + } }
pl->prog = prog; @@ -556,7 +567,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp, } bpf_cgroup_storages_free(new_storage); if (!old_prog) { - list_del(&pl->node); + hlist_del(&pl->node); kfree(pl); } return err; @@ -587,7 +598,7 @@ static void replace_effective_prog(struct cgroup *cgrp, struct cgroup_subsys_state *css; struct bpf_prog_array *progs; struct bpf_prog_list *pl; - struct list_head *head; + struct hlist_head *head; struct cgroup *cg; int pos;
@@ -603,7 +614,7 @@ static void replace_effective_prog(struct cgroup *cgrp, continue;
head = &cg->bpf.progs[atype]; - list_for_each_entry(pl, head, node) { + hlist_for_each_entry(pl, head, node) { if (!prog_list_prog(pl)) continue; if (pl->link == link) @@ -637,7 +648,7 @@ static int __cgroup_bpf_replace(struct cgroup *cgrp, enum cgroup_bpf_attach_type atype; struct bpf_prog *old_prog; struct bpf_prog_list *pl; - struct list_head *progs; + struct hlist_head *progs; bool found = false;
atype = to_cgroup_bpf_attach_type(link->type); @@ -649,7 +660,7 @@ static int __cgroup_bpf_replace(struct cgroup *cgrp, if (link->link.prog->type != new_prog->type) return -EINVAL;
- list_for_each_entry(pl, progs, node) { + hlist_for_each_entry(pl, progs, node) { if (pl->link == link) { found = true; break; @@ -688,7 +699,7 @@ static int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *new_prog, return ret; }
-static struct bpf_prog_list *find_detach_entry(struct list_head *progs, +static struct bpf_prog_list *find_detach_entry(struct hlist_head *progs, struct bpf_prog *prog, struct bpf_cgroup_link *link, bool allow_multi) @@ -696,14 +707,14 @@ static struct bpf_prog_list *find_detach_entry(struct list_head *progs, struct bpf_prog_list *pl;
if (!allow_multi) { - if (list_empty(progs)) + if (hlist_empty(progs)) /* report error when trying to detach and nothing is attached */ return ERR_PTR(-ENOENT);
/* to maintain backward compatibility NONE and OVERRIDE cgroups * allow detaching with invalid FD (prog==NULL) in legacy mode */ - return list_first_entry(progs, typeof(*pl), node); + return hlist_entry(progs->first, typeof(*pl), node); }
if (!prog && !link) @@ -713,7 +724,7 @@ static struct bpf_prog_list *find_detach_entry(struct list_head *progs, return ERR_PTR(-EINVAL);
/* find the prog or link and detach it */ - list_for_each_entry(pl, progs, node) { + hlist_for_each_entry(pl, progs, node) { if (pl->prog == prog && pl->link == link) return pl; } @@ -737,7 +748,7 @@ static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog, struct cgroup_subsys_state *css; struct bpf_prog_array *progs; struct bpf_prog_list *pl; - struct list_head *head; + struct hlist_head *head; struct cgroup *cg; int pos;
@@ -754,7 +765,7 @@ static void purge_effective_progs(struct cgroup *cgrp, struct bpf_prog *prog, continue;
head = &cg->bpf.progs[atype]; - list_for_each_entry(pl, head, node) { + hlist_for_each_entry(pl, head, node) { if (!prog_list_prog(pl)) continue; if (pl->prog == prog && pl->link == link) @@ -793,7 +804,7 @@ static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, enum cgroup_bpf_attach_type atype; struct bpf_prog *old_prog; struct bpf_prog_list *pl; - struct list_head *progs; + struct hlist_head *progs; u32 flags;
atype = to_cgroup_bpf_attach_type(type); @@ -824,9 +835,10 @@ static int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, }
/* now can actually delete it from this cgroup list */ - list_del(&pl->node); + hlist_del(&pl->node); + kfree(pl); - if (list_empty(progs)) + if (hlist_empty(progs)) /* last program was detached, reset flags to zero */ cgrp->bpf.flags[atype] = 0; if (old_prog) @@ -854,7 +866,7 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, enum bpf_attach_type type = attr->query.attach_type; enum cgroup_bpf_attach_type atype; struct bpf_prog_array *effective; - struct list_head *progs; + struct hlist_head *progs; struct bpf_prog *prog; int cnt, ret = 0, i; u32 flags; @@ -893,7 +905,7 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr, u32 id;
i = 0; - list_for_each_entry(pl, progs, node) { + hlist_for_each_entry(pl, progs, node) { prog = prog_list_prog(pl); id = prog->aux->id; if (copy_to_user(prog_ids + i, &id, sizeof(id)))