On Tue, Oct 25, 2022 at 2:54 PM Yonghong Song <yhs@xxxxxx> wrote:
>
> Similar to sk/inode/task storage, implement similar cgroup local storage.
>
> There already exists a local storage implementation for cgroup-attached
> bpf programs. See map type BPF_MAP_TYPE_CGROUP_STORAGE and helper
> bpf_get_local_storage(). But there are use cases such that non-cgroup
> attached bpf progs wants to access cgroup local storage data. For example,
> tc egress prog has access to sk and cgroup. It is possible to use
> sk local storage to emulate cgroup local storage by storing data in socket.
> But this is a waste as it could be lots of sockets belonging to a particular
> cgroup. Alternatively, a separate map can be created with cgroup id as the key.
> But this will introduce additional overhead to manipulate the new map.
> A cgroup local storage, similar to existing sk/inode/task storage,
> should help for this use case.
>
> The life-cycle of storage is managed with the life-cycle of the
> cgroup struct. i.e. the storage is destroyed along with the owning cgroup
> with a call to bpf_cgrp_storage_free() when cgroup itself
> is deleted.
>
> The userspace map operations can be done by using a cgroup fd as a key
> passed to the lookup, update and delete operations.
>
> Typically, the following code is used to get the current cgroup:
> struct task_struct *task = bpf_get_current_task_btf();
> ... task->cgroups->dfl_cgrp ...
> and in structure task_struct definition:
> struct task_struct {
> ....
> struct css_set __rcu *cgroups;
> ....
> }
> With sleepable program, accessing task->cgroups is not protected by rcu_read_lock.
> So the current implementation only supports non-sleepable program and supporting
> sleepable program will be the next step together with adding rcu_read_lock
> protection for rcu tagged structures.
>
> Since map name BPF_MAP_TYPE_CGROUP_STORAGE has been used for old cgroup local
> storage support, the new map name BPF_MAP_TYPE_CGRP_STORAGE is used
> for cgroup storage available to non-cgroup-attached bpf programs. The old
> cgroup storage supports bpf_get_local_storage() helper to get the cgroup data.
> The new cgroup storage helper bpf_cgrp_storage_get() can provide similar
> functionality. While old cgroup storage pre-allocates storage memory, the new
> mechanism can also pre-allocate with a user space bpf_map_update_elem() call
> to avoid potential run-time memory allocation failure.
> Therefore, the new cgroup storage can provide all functionality w.r.t.
> the old one. So in uapi bpf.h, the old BPF_MAP_TYPE_CGROUP_STORAGE is alias to
> BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED to indicate the old cgroup storage can
> be deprecated since the new one can provide the same functionality.
>
> Acked-by: David Vernet <void@xxxxxxxxxxxxx>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
> include/linux/bpf.h | 7 +
> include/linux/bpf_types.h | 1 +
> include/linux/cgroup-defs.h | 4 +
> include/uapi/linux/bpf.h | 50 ++++++-
> kernel/bpf/Makefile | 2 +-
> kernel/bpf/bpf_cgrp_storage.c | 247 +++++++++++++++++++++++++++++++++
> kernel/bpf/helpers.c | 6 +
> kernel/bpf/syscall.c | 3 +-
> kernel/bpf/verifier.c | 13 +-
> kernel/cgroup/cgroup.c | 1 +
> kernel/trace/bpf_trace.c | 4 +
> scripts/bpf_doc.py | 2 +
> tools/include/uapi/linux/bpf.h | 50 ++++++-
> 13 files changed, 385 insertions(+), 5 deletions(-)
> create mode 100644 kernel/bpf/bpf_cgrp_storage.c
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 9e7d46d16032..0fa3b4f6e777 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -2045,6 +2045,7 @@ struct bpf_link *bpf_link_by_id(u32 id);
>
> const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id);
> void bpf_task_storage_free(struct task_struct *task);
> +void bpf_cgrp_storage_free(struct cgroup *cgroup);
> bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog);
> const struct btf_func_model *
> bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
> @@ -2299,6 +2300,10 @@ static inline bool has_current_bpf_ctx(void)
> static inline void bpf_prog_inc_misses_counter(struct bpf_prog *prog)
> {
> }
> +
> +static inline void bpf_cgrp_storage_free(struct cgroup *cgroup)
> +{
> +}
> #endif /* CONFIG_BPF_SYSCALL */
>
> void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
> @@ -2537,6 +2542,8 @@ extern const struct bpf_func_proto bpf_copy_from_user_task_proto;
> extern const struct bpf_func_proto bpf_set_retval_proto;
> extern const struct bpf_func_proto bpf_get_retval_proto;
> extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
> +extern const struct bpf_func_proto bpf_cgrp_storage_get_proto;
> +extern const struct bpf_func_proto bpf_cgrp_storage_delete_proto;
>
> const struct bpf_func_proto *tracing_prog_func_proto(
> enum bpf_func_id func_id, const struct bpf_prog *prog);
> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> index 2c6a4f2562a7..d4ee3ccd3753 100644
> --- a/include/linux/bpf_types.h
> +++ b/include/linux/bpf_types.h
> @@ -86,6 +86,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_PROG_ARRAY, prog_array_map_ops)
> BPF_MAP_TYPE(BPF_MAP_TYPE_PERF_EVENT_ARRAY, perf_event_array_map_ops)
> #ifdef CONFIG_CGROUPS
> BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_ARRAY, cgroup_array_map_ops)
> +BPF_MAP_TYPE(BPF_MAP_TYPE_CGRP_STORAGE, cgrp_storage_map_ops)
> #endif
> #ifdef CONFIG_CGROUP_BPF
> BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_STORAGE, cgroup_storage_map_ops)
> diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
> index 8f481d1b159a..c466fdc3a32a 100644
> --- a/include/linux/cgroup-defs.h
> +++ b/include/linux/cgroup-defs.h
> @@ -504,6 +504,10 @@ struct cgroup {
> /* Used to store internal freezer state */
> struct cgroup_freezer_state freezer;
>
> +#ifdef CONFIG_BPF_SYSCALL
> + struct bpf_local_storage __rcu *bpf_cgrp_storage;
> +#endif
> +
> /* All ancestors including self */
> struct cgroup *ancestors[];
> };
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 17f61338f8f8..94659f6b3395 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -922,7 +922,14 @@ enum bpf_map_type {
> BPF_MAP_TYPE_CPUMAP,
> BPF_MAP_TYPE_XSKMAP,
> BPF_MAP_TYPE_SOCKHASH,
> - BPF_MAP_TYPE_CGROUP_STORAGE,
> + BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
> + /* BPF_MAP_TYPE_CGROUP_STORAGE is available to bpf programs attaching
> + * to a cgroup. The newer BPF_MAP_TYPE_CGRP_STORAGE is available to
> + * both cgroup-attached and other progs and supports all functionality
> + * provided by BPF_MAP_TYPE_CGROUP_STORAGE. So mark
> + * BPF_MAP_TYPE_CGROUP_STORAGE deprecated.
> + */
> + BPF_MAP_TYPE_CGROUP_STORAGE = BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
> BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
> BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
> BPF_MAP_TYPE_QUEUE,
> @@ -935,6 +942,7 @@ enum bpf_map_type {
> BPF_MAP_TYPE_TASK_STORAGE,
> BPF_MAP_TYPE_BLOOM_FILTER,
> BPF_MAP_TYPE_USER_RINGBUF,
> + BPF_MAP_TYPE_CGRP_STORAGE,
> };
>
> /* Note that tracing related programs such as
> @@ -5435,6 +5443,44 @@ union bpf_attr {
> * **-E2BIG** if user-space has tried to publish a sample which is
> * larger than the size of the ring buffer, or which cannot fit
> * within a struct bpf_dynptr.
> + *
> + * void *bpf_cgrp_storage_get(struct bpf_map *map, struct cgroup *cgroup, void *value, u64 flags)
> + * Description
> + * Get a bpf_local_storage from the *cgroup*.
> + *
> + * Logically, it could be thought of as getting the value from
> + * a *map* with *cgroup* as the **key**. From this
> + * perspective, the usage is not much different from
> + * **bpf_map_lookup_elem**\ (*map*, **&**\ *cgroup*) except this
> + * helper enforces the key must be a cgroup struct and the map must also
> + * be a **BPF_MAP_TYPE_CGRP_STORAGE**.
> + *
> + * In reality, the local-storage value is embedded directly inside of the
> + * *cgroup* object itself, rather than being located in the
> + * **BPF_MAP_TYPE_CGRP_STORAGE** map. When the local-storage value is
> + * queried for some *map* on a *cgroup* object, the kernel will perform an
> + * O(n) iteration over all of the live local-storage values for that
> + * *cgroup* object until the local-storage value for the *map* is found.
> + *
> + * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
> + * used such that a new bpf_local_storage will be
> + * created if one does not exist. *value* can be used
> + * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
> + * the initial value of a bpf_local_storage. If *value* is
> + * **NULL**, the new bpf_local_storage will be zero initialized.
> + * Return
> + * A bpf_local_storage pointer is returned on success.
> + *
> + * **NULL** if not found or there was an error in adding
> + * a new bpf_local_storage.
> + *
> + * long bpf_cgrp_storage_delete(struct bpf_map *map, struct cgroup *cgroup)
> + * Description
> + * Delete a bpf_local_storage from a *cgroup*.
> + * Return
> + * 0 on success.
> + *
> + * **-ENOENT** if the bpf_local_storage cannot be found.
> */
> #define ___BPF_FUNC_MAPPER(FN, ctx...) \
> FN(unspec, 0, ##ctx) \
> @@ -5647,6 +5693,8 @@ union bpf_attr {
> FN(tcp_raw_check_syncookie_ipv6, 207, ##ctx) \
> FN(ktime_get_tai_ns, 208, ##ctx) \
> FN(user_ringbuf_drain, 209, ##ctx) \
> + FN(cgrp_storage_get, 210, ##ctx) \
> + FN(cgrp_storage_delete, 211, ##ctx) \
> /* */
>
> /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
> diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
> index 341c94f208f4..3a12e6b400a2 100644
> --- a/kernel/bpf/Makefile
> +++ b/kernel/bpf/Makefile
> @@ -25,7 +25,7 @@ ifeq ($(CONFIG_PERF_EVENTS),y)
> obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
> endif
> ifeq ($(CONFIG_CGROUPS),y)
> -obj-$(CONFIG_BPF_SYSCALL) += cgroup_iter.o
> +obj-$(CONFIG_BPF_SYSCALL) += cgroup_iter.o bpf_cgrp_storage.o
> endif
> obj-$(CONFIG_CGROUP_BPF) += cgroup.o
> ifeq ($(CONFIG_INET),y)
> diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c
> new file mode 100644
> index 000000000000..309403800f82
> --- /dev/null
> +++ b/kernel/bpf/bpf_cgrp_storage.c
> @@ -0,0 +1,247 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
> + */
> +
> +#include <linux/types.h>
> +#include <linux/bpf.h>
> +#include <linux/bpf_local_storage.h>
> +#include <uapi/linux/btf.h>
> +#include <linux/btf_ids.h>
> +
> +DEFINE_BPF_STORAGE_CACHE(cgroup_cache);
> +
> +static DEFINE_PER_CPU(int, bpf_cgrp_storage_busy);
> +
> +static void bpf_cgrp_storage_lock(void)
> +{
> + migrate_disable();
> + this_cpu_inc(bpf_cgrp_storage_busy);
> +}
> +
> +static void bpf_cgrp_storage_unlock(void)
> +{
> + this_cpu_dec(bpf_cgrp_storage_busy);
> + migrate_enable();
> +}
> +
> +static bool bpf_cgrp_storage_trylock(void)
> +{
> + migrate_disable();
> + if (unlikely(this_cpu_inc_return(bpf_cgrp_storage_busy) != 1)) {
> + this_cpu_dec(bpf_cgrp_storage_busy);
> + migrate_enable();
> + return false;
> + }
> + return true;
> +}
> +
> +static struct bpf_local_storage __rcu **cgroup_storage_ptr(void *owner)
> +{
> + struct cgroup *cg = owner;
> +
> + return &cg->bpf_cgrp_storage;
> +}
> +
> +void bpf_cgrp_storage_free(struct cgroup *cgroup)
> +{
> + struct bpf_local_storage *local_storage;
> + bool free_cgroup_storage = false;
> + unsigned long flags;
> +
> + rcu_read_lock();
> + local_storage = rcu_dereference(cgroup->bpf_cgrp_storage);
> + if (!local_storage) {
> + rcu_read_unlock();
> + return;
> + }
> +
> + bpf_cgrp_storage_lock();
> + raw_spin_lock_irqsave(&local_storage->lock, flags);
> + free_cgroup_storage = bpf_local_storage_unlink_nolock(local_storage);
> + raw_spin_unlock_irqrestore(&local_storage->lock, flags);
> + bpf_cgrp_storage_unlock();
> + rcu_read_unlock();
> +
> + if (free_cgroup_storage)
> + kfree_rcu(local_storage, rcu);
> +}
> +
> +static struct bpf_local_storage_data *
> +cgroup_storage_lookup(struct cgroup *cgroup, struct bpf_map *map, bool cacheit_lockit)
> +{
> + struct bpf_local_storage *cgroup_storage;
> + struct bpf_local_storage_map *smap;
> +
> + cgroup_storage = rcu_dereference_check(cgroup->bpf_cgrp_storage,
> + bpf_rcu_lock_held());
> + if (!cgroup_storage)
> + return NULL;
> +
> + smap = (struct bpf_local_storage_map *)map;
> + return bpf_local_storage_lookup(cgroup_storage, smap, cacheit_lockit);
> +}
> +
> +static void *bpf_cgrp_storage_lookup_elem(struct bpf_map *map, void *key)
> +{
> + struct bpf_local_storage_data *sdata;
> + struct cgroup *cgroup;
> + int fd;
> +
> + fd = *(int *)key;
> + cgroup = cgroup_get_from_fd(fd);
Sorry I didn't notice this before, but is there a reason why only
cgroup v2 is supported here?
Can we also support cgroup v1 by using cgroup_v1v2_get_from_fd()
instead, similar to cgroup_iter? or is there something else in the
implementation that is cgroup v2 specific?
> + if (IS_ERR(cgroup))
> + return ERR_CAST(cgroup);
> +
> + bpf_cgrp_storage_lock();
> + sdata = cgroup_storage_lookup(cgroup, map, true);
> + bpf_cgrp_storage_unlock();
> + cgroup_put(cgroup);
> + return sdata ? sdata->data : NULL;
> +}
> +
> +static int bpf_cgrp_storage_update_elem(struct bpf_map *map, void *key,
> + void *value, u64 map_flags)
> +{
> + struct bpf_local_storage_data *sdata;
> + struct cgroup *cgroup;
> + int fd;
> +
> + fd = *(int *)key;
> + cgroup = cgroup_get_from_fd(fd);
> + if (IS_ERR(cgroup))
> + return PTR_ERR(cgroup);
> +
> + bpf_cgrp_storage_lock();
> + sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map,
> + value, map_flags, GFP_ATOMIC);
> + bpf_cgrp_storage_unlock();
> + cgroup_put(cgroup);
> + return PTR_ERR_OR_ZERO(sdata);
> +}
> +
> +static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map)
> +{
> + struct bpf_local_storage_data *sdata;
> +
> + sdata = cgroup_storage_lookup(cgroup, map, false);
> + if (!sdata)
> + return -ENOENT;
> +
> + bpf_selem_unlink(SELEM(sdata), true);
> + return 0;
> +}
> +
> +static int bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key)
> +{
> + struct cgroup *cgroup;
> + int err, fd;
> +
> + fd = *(int *)key;
> + cgroup = cgroup_get_from_fd(fd);
> + if (IS_ERR(cgroup))
> + return PTR_ERR(cgroup);
> +
> + bpf_cgrp_storage_lock();
> + err = cgroup_storage_delete(cgroup, map);
> + bpf_cgrp_storage_unlock();
> + cgroup_put(cgroup);
> + return err;
> +}
> +
> +static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static struct bpf_map *cgroup_storage_map_alloc(union bpf_attr *attr)
> +{
> + return bpf_local_storage_map_alloc(attr, &cgroup_cache);
> +}
> +
> +static void cgroup_storage_map_free(struct bpf_map *map)
> +{
> + bpf_local_storage_map_free(map, &cgroup_cache, NULL);
> +}
> +
> +/* *gfp_flags* is a hidden argument provided by the verifier */
> +BPF_CALL_5(bpf_cgrp_storage_get, struct bpf_map *, map, struct cgroup *, cgroup,
> + void *, value, u64, flags, gfp_t, gfp_flags)
> +{
> + struct bpf_local_storage_data *sdata;
> +
> + WARN_ON_ONCE(!bpf_rcu_lock_held());
> + if (flags & ~(BPF_LOCAL_STORAGE_GET_F_CREATE))
> + return (unsigned long)NULL;
> +
> + if (!cgroup)
> + return (unsigned long)NULL;
> +
> + if (!bpf_cgrp_storage_trylock())
> + return (unsigned long)NULL;
> +
> + sdata = cgroup_storage_lookup(cgroup, map, true);
> + if (sdata)
> + goto unlock;
> +
> + /* only allocate new storage, when the cgroup is refcounted */
> + if (!percpu_ref_is_dying(&cgroup->self.refcnt) &&
> + (flags & BPF_LOCAL_STORAGE_GET_F_CREATE))
> + sdata = bpf_local_storage_update(cgroup, (struct bpf_local_storage_map *)map,
> + value, BPF_NOEXIST, gfp_flags);
> +
> +unlock:
> + bpf_cgrp_storage_unlock();
> + return IS_ERR_OR_NULL(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data;
> +}
> +
> +BPF_CALL_2(bpf_cgrp_storage_delete, struct bpf_map *, map, struct cgroup *, cgroup)
> +{
> + int ret;
> +
> + WARN_ON_ONCE(!bpf_rcu_lock_held());
> + if (!cgroup)
> + return -EINVAL;
> +
> + if (!bpf_cgrp_storage_trylock())
> + return -EBUSY;
> +
> + ret = cgroup_storage_delete(cgroup, map);
> + bpf_cgrp_storage_unlock();
> + return ret;
> +}
> +
> +BTF_ID_LIST_SINGLE(cgroup_storage_map_btf_ids, struct, bpf_local_storage_map)
> +const struct bpf_map_ops cgrp_storage_map_ops = {
> + .map_meta_equal = bpf_map_meta_equal,
> + .map_alloc_check = bpf_local_storage_map_alloc_check,
> + .map_alloc = cgroup_storage_map_alloc,
> + .map_free = cgroup_storage_map_free,
> + .map_get_next_key = notsupp_get_next_key,
> + .map_lookup_elem = bpf_cgrp_storage_lookup_elem,
> + .map_update_elem = bpf_cgrp_storage_update_elem,
> + .map_delete_elem = bpf_cgrp_storage_delete_elem,
> + .map_check_btf = bpf_local_storage_map_check_btf,
> + .map_btf_id = &cgroup_storage_map_btf_ids[0],
> + .map_owner_storage_ptr = cgroup_storage_ptr,
> +};
> +
> +const struct bpf_func_proto bpf_cgrp_storage_get_proto = {
> + .func = bpf_cgrp_storage_get,
> + .gpl_only = false,
> + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
> + .arg1_type = ARG_CONST_MAP_PTR,
> + .arg2_type = ARG_PTR_TO_BTF_ID,
> + .arg2_btf_id = &bpf_cgroup_btf_id[0],
> + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
> + .arg4_type = ARG_ANYTHING,
> +};
> +
> +const struct bpf_func_proto bpf_cgrp_storage_delete_proto = {
> + .func = bpf_cgrp_storage_delete,
> + .gpl_only = false,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_CONST_MAP_PTR,
> + .arg2_type = ARG_PTR_TO_BTF_ID,
> + .arg2_btf_id = &bpf_cgroup_btf_id[0],
> +};
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index a6b04faed282..124fd199ce5c 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -1663,6 +1663,12 @@ bpf_base_func_proto(enum bpf_func_id func_id)
> return &bpf_dynptr_write_proto;
> case BPF_FUNC_dynptr_data:
> return &bpf_dynptr_data_proto;
> +#ifdef CONFIG_CGROUPS
> + case BPF_FUNC_cgrp_storage_get:
> + return &bpf_cgrp_storage_get_proto;
> + case BPF_FUNC_cgrp_storage_delete:
> + return &bpf_cgrp_storage_delete_proto;
> +#endif
> default:
> break;
> }
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 7b373a5e861f..b95c276f92e3 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -1016,7 +1016,8 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
> map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
> map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
> map->map_type != BPF_MAP_TYPE_INODE_STORAGE &&
> - map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
> + map->map_type != BPF_MAP_TYPE_TASK_STORAGE &&
> + map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
> return -ENOTSUPP;
> if (map->spin_lock_off + sizeof(struct bpf_spin_lock) >
> map->value_size) {
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index ddc1452cf023..8f849a763b79 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -6350,6 +6350,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
> func_id != BPF_FUNC_task_storage_delete)
> goto error;
> break;
> + case BPF_MAP_TYPE_CGRP_STORAGE:
> + if (func_id != BPF_FUNC_cgrp_storage_get &&
> + func_id != BPF_FUNC_cgrp_storage_delete)
> + goto error;
> + break;
> case BPF_MAP_TYPE_BLOOM_FILTER:
> if (func_id != BPF_FUNC_map_peek_elem &&
> func_id != BPF_FUNC_map_push_elem)
> @@ -6462,6 +6467,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
> if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
> goto error;
> break;
> + case BPF_FUNC_cgrp_storage_get:
> + case BPF_FUNC_cgrp_storage_delete:
> + if (map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
> + goto error;
> + break;
> default:
> break;
> }
> @@ -14139,7 +14149,8 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
>
> if (insn->imm == BPF_FUNC_task_storage_get ||
> insn->imm == BPF_FUNC_sk_storage_get ||
> - insn->imm == BPF_FUNC_inode_storage_get) {
> + insn->imm == BPF_FUNC_inode_storage_get ||
> + insn->imm == BPF_FUNC_cgrp_storage_get) {
> if (env->prog->aux->sleepable)
> insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
> else
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index 764bdd5fd8d1..12001928511b 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -5245,6 +5245,7 @@ static void css_free_rwork_fn(struct work_struct *work)
> atomic_dec(&cgrp->root->nr_cgrps);
> cgroup1_pidlist_destroy_all(cgrp);
> cancel_work_sync(&cgrp->release_agent_work);
> + bpf_cgrp_storage_free(cgrp);
>
> if (cgroup_parent(cgrp)) {
> /*
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 2460e38f75ff..e7d919194f82 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1454,6 +1454,10 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> return &bpf_get_current_cgroup_id_proto;
> case BPF_FUNC_get_current_ancestor_cgroup_id:
> return &bpf_get_current_ancestor_cgroup_id_proto;
> + case BPF_FUNC_cgrp_storage_get:
> + return &bpf_cgrp_storage_get_proto;
> + case BPF_FUNC_cgrp_storage_delete:
> + return &bpf_cgrp_storage_delete_proto;
> #endif
> case BPF_FUNC_send_signal:
> return &bpf_send_signal_proto;
> diff --git a/scripts/bpf_doc.py b/scripts/bpf_doc.py
> index c0e6690be82a..fdb0aff8cb5a 100755
> --- a/scripts/bpf_doc.py
> +++ b/scripts/bpf_doc.py
> @@ -685,6 +685,7 @@ class PrinterHelpers(Printer):
> 'struct udp6_sock',
> 'struct unix_sock',
> 'struct task_struct',
> + 'struct cgroup',
>
> 'struct __sk_buff',
> 'struct sk_msg_md',
> @@ -742,6 +743,7 @@ class PrinterHelpers(Printer):
> 'struct udp6_sock',
> 'struct unix_sock',
> 'struct task_struct',
> + 'struct cgroup',
> 'struct path',
> 'struct btf_ptr',
> 'struct inode',
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 17f61338f8f8..94659f6b3395 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -922,7 +922,14 @@ enum bpf_map_type {
> BPF_MAP_TYPE_CPUMAP,
> BPF_MAP_TYPE_XSKMAP,
> BPF_MAP_TYPE_SOCKHASH,
> - BPF_MAP_TYPE_CGROUP_STORAGE,
> + BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
> + /* BPF_MAP_TYPE_CGROUP_STORAGE is available to bpf programs attaching
> + * to a cgroup. The newer BPF_MAP_TYPE_CGRP_STORAGE is available to
> + * both cgroup-attached and other progs and supports all functionality
> + * provided by BPF_MAP_TYPE_CGROUP_STORAGE. So mark
> + * BPF_MAP_TYPE_CGROUP_STORAGE deprecated.
> + */
> + BPF_MAP_TYPE_CGROUP_STORAGE = BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
> BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
> BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
> BPF_MAP_TYPE_QUEUE,
> @@ -935,6 +942,7 @@ enum bpf_map_type {
> BPF_MAP_TYPE_TASK_STORAGE,
> BPF_MAP_TYPE_BLOOM_FILTER,
> BPF_MAP_TYPE_USER_RINGBUF,
> + BPF_MAP_TYPE_CGRP_STORAGE,
> };
>
> /* Note that tracing related programs such as
> @@ -5435,6 +5443,44 @@ union bpf_attr {
> * **-E2BIG** if user-space has tried to publish a sample which is
> * larger than the size of the ring buffer, or which cannot fit
> * within a struct bpf_dynptr.
> + *
> + * void *bpf_cgrp_storage_get(struct bpf_map *map, struct cgroup *cgroup, void *value, u64 flags)
> + * Description
> + * Get a bpf_local_storage from the *cgroup*.
> + *
> + * Logically, it could be thought of as getting the value from
> + * a *map* with *cgroup* as the **key**. From this
> + * perspective, the usage is not much different from
> + * **bpf_map_lookup_elem**\ (*map*, **&**\ *cgroup*) except this
> + * helper enforces the key must be a cgroup struct and the map must also
> + * be a **BPF_MAP_TYPE_CGRP_STORAGE**.
> + *
> + * In reality, the local-storage value is embedded directly inside of the
> + * *cgroup* object itself, rather than being located in the
> + * **BPF_MAP_TYPE_CGRP_STORAGE** map. When the local-storage value is
> + * queried for some *map* on a *cgroup* object, the kernel will perform an
> + * O(n) iteration over all of the live local-storage values for that
> + * *cgroup* object until the local-storage value for the *map* is found.
> + *
> + * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
> + * used such that a new bpf_local_storage will be
> + * created if one does not exist. *value* can be used
> + * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
> + * the initial value of a bpf_local_storage. If *value* is
> + * **NULL**, the new bpf_local_storage will be zero initialized.
> + * Return
> + * A bpf_local_storage pointer is returned on success.
> + *
> + * **NULL** if not found or there was an error in adding
> + * a new bpf_local_storage.
> + *
> + * long bpf_cgrp_storage_delete(struct bpf_map *map, struct cgroup *cgroup)
> + * Description
> + * Delete a bpf_local_storage from a *cgroup*.
> + * Return
> + * 0 on success.
> + *
> + * **-ENOENT** if the bpf_local_storage cannot be found.
> */
> #define ___BPF_FUNC_MAPPER(FN, ctx...) \
> FN(unspec, 0, ##ctx) \
> @@ -5647,6 +5693,8 @@ union bpf_attr {
> FN(tcp_raw_check_syncookie_ipv6, 207, ##ctx) \
> FN(ktime_get_tai_ns, 208, ##ctx) \
> FN(user_ringbuf_drain, 209, ##ctx) \
> + FN(cgrp_storage_get, 210, ##ctx) \
> + FN(cgrp_storage_delete, 211, ##ctx) \
> /* */
>
> /* backwards-compatibility macros for users of __BPF_FUNC_MAPPER that don't
> --
> 2.30.2
>
