bpf: Factor out cgroup storages operations
Refactor cgroup attach/detach code to abstract away common operations performed on all types of cgroup storages. This makes high-level logic more apparent, plus allows to reuse more code across multiple functions. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200325065746.640559-2-andriin@fb.com
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
aa131ed44a
commit
00c4eddf7e
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@ -28,6 +28,58 @@ void cgroup_bpf_offline(struct cgroup *cgrp)
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percpu_ref_kill(&cgrp->bpf.refcnt);
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}
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static void bpf_cgroup_storages_free(struct bpf_cgroup_storage *storages[])
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{
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enum bpf_cgroup_storage_type stype;
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_free(storages[stype]);
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}
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static int bpf_cgroup_storages_alloc(struct bpf_cgroup_storage *storages[],
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struct bpf_prog *prog)
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{
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enum bpf_cgroup_storage_type stype;
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for_each_cgroup_storage_type(stype) {
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storages[stype] = bpf_cgroup_storage_alloc(prog, stype);
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if (IS_ERR(storages[stype])) {
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storages[stype] = NULL;
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bpf_cgroup_storages_free(storages);
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return -ENOMEM;
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}
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}
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return 0;
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}
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static void bpf_cgroup_storages_assign(struct bpf_cgroup_storage *dst[],
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struct bpf_cgroup_storage *src[])
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{
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enum bpf_cgroup_storage_type stype;
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for_each_cgroup_storage_type(stype)
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dst[stype] = src[stype];
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}
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static void bpf_cgroup_storages_link(struct bpf_cgroup_storage *storages[],
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struct cgroup* cgrp,
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enum bpf_attach_type attach_type)
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{
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enum bpf_cgroup_storage_type stype;
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_link(storages[stype], cgrp, attach_type);
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}
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static void bpf_cgroup_storages_unlink(struct bpf_cgroup_storage *storages[])
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{
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enum bpf_cgroup_storage_type stype;
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_unlink(storages[stype]);
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}
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/**
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* cgroup_bpf_release() - put references of all bpf programs and
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* release all cgroup bpf data
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@ -37,7 +89,6 @@ static void cgroup_bpf_release(struct work_struct *work)
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{
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struct cgroup *p, *cgrp = container_of(work, struct cgroup,
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bpf.release_work);
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enum bpf_cgroup_storage_type stype;
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struct bpf_prog_array *old_array;
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unsigned int type;
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@ -50,10 +101,8 @@ static void cgroup_bpf_release(struct work_struct *work)
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list_for_each_entry_safe(pl, tmp, progs, node) {
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list_del(&pl->node);
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bpf_prog_put(pl->prog);
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for_each_cgroup_storage_type(stype) {
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bpf_cgroup_storage_unlink(pl->storage[stype]);
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bpf_cgroup_storage_free(pl->storage[stype]);
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}
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bpf_cgroup_storages_unlink(pl->storage);
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bpf_cgroup_storages_free(pl->storage);
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kfree(pl);
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static_branch_dec(&cgroup_bpf_enabled_key);
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}
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@ -138,7 +187,7 @@ static int compute_effective_progs(struct cgroup *cgrp,
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enum bpf_attach_type type,
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struct bpf_prog_array **array)
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{
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enum bpf_cgroup_storage_type stype;
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struct bpf_prog_array_item *item;
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struct bpf_prog_array *progs;
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struct bpf_prog_list *pl;
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struct cgroup *p = cgrp;
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@ -166,10 +215,10 @@ static int compute_effective_progs(struct cgroup *cgrp,
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if (!pl->prog)
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continue;
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progs->items[cnt].prog = pl->prog;
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for_each_cgroup_storage_type(stype)
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progs->items[cnt].cgroup_storage[stype] =
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pl->storage[stype];
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item = &progs->items[cnt];
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item->prog = pl->prog;
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bpf_cgroup_storages_assign(item->cgroup_storage,
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pl->storage);
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cnt++;
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}
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} while ((p = cgroup_parent(p)));
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@ -305,7 +354,6 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
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struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE],
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*old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {NULL};
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struct bpf_prog_list *pl, *replace_pl = NULL;
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enum bpf_cgroup_storage_type stype;
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int err;
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if (((flags & BPF_F_ALLOW_OVERRIDE) && (flags & BPF_F_ALLOW_MULTI)) ||
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@ -341,37 +389,25 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
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replace_pl = list_first_entry(progs, typeof(*pl), node);
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}
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for_each_cgroup_storage_type(stype) {
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storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
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if (IS_ERR(storage[stype])) {
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storage[stype] = NULL;
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_free(storage[stype]);
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return -ENOMEM;
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}
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}
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if (bpf_cgroup_storages_alloc(storage, prog))
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return -ENOMEM;
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if (replace_pl) {
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pl = replace_pl;
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old_prog = pl->prog;
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for_each_cgroup_storage_type(stype) {
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old_storage[stype] = pl->storage[stype];
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bpf_cgroup_storage_unlink(old_storage[stype]);
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}
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bpf_cgroup_storages_unlink(pl->storage);
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bpf_cgroup_storages_assign(old_storage, pl->storage);
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} else {
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pl = kmalloc(sizeof(*pl), GFP_KERNEL);
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if (!pl) {
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_free(storage[stype]);
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bpf_cgroup_storages_free(storage);
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return -ENOMEM;
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}
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list_add_tail(&pl->node, progs);
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}
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pl->prog = prog;
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for_each_cgroup_storage_type(stype)
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pl->storage[stype] = storage[stype];
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bpf_cgroup_storages_assign(pl->storage, storage);
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cgrp->bpf.flags[type] = saved_flags;
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err = update_effective_progs(cgrp, type);
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@ -379,27 +415,20 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
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goto cleanup;
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static_branch_inc(&cgroup_bpf_enabled_key);
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for_each_cgroup_storage_type(stype) {
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if (!old_storage[stype])
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continue;
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bpf_cgroup_storage_free(old_storage[stype]);
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}
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bpf_cgroup_storages_free(old_storage);
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if (old_prog) {
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bpf_prog_put(old_prog);
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static_branch_dec(&cgroup_bpf_enabled_key);
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}
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for_each_cgroup_storage_type(stype)
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bpf_cgroup_storage_link(storage[stype], cgrp, type);
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bpf_cgroup_storages_link(storage, cgrp, type);
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return 0;
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cleanup:
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/* and cleanup the prog list */
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pl->prog = old_prog;
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for_each_cgroup_storage_type(stype) {
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bpf_cgroup_storage_free(pl->storage[stype]);
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pl->storage[stype] = old_storage[stype];
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bpf_cgroup_storage_link(old_storage[stype], cgrp, type);
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}
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bpf_cgroup_storages_free(pl->storage);
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bpf_cgroup_storages_assign(pl->storage, old_storage);
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bpf_cgroup_storages_link(pl->storage, cgrp, type);
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if (!replace_pl) {
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list_del(&pl->node);
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kfree(pl);
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@ -420,7 +449,6 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
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enum bpf_attach_type type)
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{
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struct list_head *progs = &cgrp->bpf.progs[type];
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enum bpf_cgroup_storage_type stype;
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u32 flags = cgrp->bpf.flags[type];
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struct bpf_prog *old_prog = NULL;
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struct bpf_prog_list *pl;
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@ -467,10 +495,8 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
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/* now can actually delete it from this cgroup list */
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list_del(&pl->node);
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for_each_cgroup_storage_type(stype) {
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bpf_cgroup_storage_unlink(pl->storage[stype]);
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bpf_cgroup_storage_free(pl->storage[stype]);
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}
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bpf_cgroup_storages_unlink(pl->storage);
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bpf_cgroup_storages_free(pl->storage);
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kfree(pl);
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if (list_empty(progs))
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/* last program was detached, reset flags to zero */
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