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authorYonghong Song <yhs@fb.com>2022-10-26 07:28:50 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-10-26 09:19:19 +0300
commitc4bcfb38a95edb1021a53f2d0356a78120ecfbe4 (patch)
tree81ab4ff10698e9c4297f438bdb7c129c43820f78
parentc83597fa5dc6b322e9bdf929e5f4136a3f4aa4db (diff)
downloadlinux-c4bcfb38a95edb1021a53f2d0356a78120ecfbe4.tar.xz
bpf: Implement cgroup storage available to non-cgroup-attached bpf progs
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@manifault.com> Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20221026042850.673791-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--include/linux/bpf.h7
-rw-r--r--include/linux/bpf_types.h1
-rw-r--r--include/linux/cgroup-defs.h4
-rw-r--r--include/uapi/linux/bpf.h50
-rw-r--r--kernel/bpf/Makefile2
-rw-r--r--kernel/bpf/bpf_cgrp_storage.c247
-rw-r--r--kernel/bpf/helpers.c6
-rw-r--r--kernel/bpf/syscall.c3
-rw-r--r--kernel/bpf/verifier.c13
-rw-r--r--kernel/cgroup/cgroup.c1
-rw-r--r--kernel/trace/bpf_trace.c4
-rwxr-xr-xscripts/bpf_doc.py2
-rw-r--r--tools/include/uapi/linux/bpf.h50
13 files changed, 385 insertions, 5 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a5dbac8f5aba..9fd68b0b3e9c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2041,6 +2041,7 @@ 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,
@@ -2295,6 +2296,10 @@ 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,
@@ -2535,6 +2540,8 @@ 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);
+ 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 a0b4266196a8..11df90962101 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 eed1bd952c3a..ce0228c72a93 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1455,6 +1455,10 @@ 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