[PATCH bpf-next v6 0/9] bpf: Implement cgroup local storage available to non-cgroup-attached bpf progs

[PATCH bpf-next v6 0/9] bpf: Implement cgroup local storage available to non-cgroup-attached bpf progs

[Yonghong Song]

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.

This patch implemented new cgroup local storage available to
non-cgroup-attached bpf programs. In the patch series, Patches 1 and 2
are preparation patches. Patch 3 implemented new cgroup local storage
kernel support. Patches 4 and 5 implemented libbpf and bpftool support.
Patches 6-8 fixed one existing test and added four new tests to validate
kernel/libbpf implementations. Patch 9 added documentation for new
BPF_MAP_TYPE_CGRP_STORAGE map type and comparison of the old and new
cgroup local storage maps.

Changelogs:
  v5 -> v6:
    . fix selftest test_libbpf_str/bpf_map_type_str due to marking
      BPF_MAP_TYPE_CGROUP_STORAGE as deprecated.
    . add cgrp_local_storage test in s390x denylist since the test
      has some fentry/fexit programs.
  v4 -> v5:
    . additional refactoring in patch 2
    . fix the call site for bpf_cgrp_storage_free() in kernel/cgroup/cgroup.c.
    . add a test for progs attaching to cgroups
    . add a negative test (the helper key is a task instead of expected cgroup)
    . some spelling fixes
  v3 -> v4:
    . fix a config guarding problem in kernel/cgroup/cgroup.c when
      cgrp_storage is deleted (CONFIG_CGROUP_BPF => CONFIG_BPF_SYSCALL).
    . rename selftest from cgroup_local_storage.c to cgrp_local_storage.c
      so the name can better align with map name.
    . fix a few misspellings.
  v2 -> v3:
    . fix a config caused kernel test complaint.
    . better description/comments in uapi bpf.h and bpf_cgrp_storage.c.
    . factor code for better resue for map_alloc/map_free.
    . improved explanation in map documentation.
  v1 -> v2:
    . change map name from BPF_MAP_TYPE_CGROUP_LOCAL_STORAGE to
      BPF_MAP_TYPE_CGRP_STORAGE.
    . removed support of sleepable programs.
    . changed the place of freeing cgrp local storage from put_css_set_locked()
      to css_free_rwork_fn().
    . added map documentation.

Yonghong Song (9):
  bpf: Make struct cgroup btf id global
  bpf: Refactor some inode/task/sk storage functions for reuse
  bpf: Implement cgroup storage available to non-cgroup-attached bpf
    progs
  libbpf: Support new cgroup local storage
  bpftool: Support new cgroup local storage
  selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str
  selftests/bpf: Add selftests for new cgroup local storage
  selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x
  docs/bpf: Add documentation for new cgroup local storage

 Documentation/bpf/map_cgrp_storage.rst        | 109 ++++++++
 include/linux/bpf.h                           |   7 +
 include/linux/bpf_local_storage.h             |  17 +-
 include/linux/bpf_types.h                     |   1 +
 include/linux/btf_ids.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/bpf_inode_storage.c                |  38 +--
 kernel/bpf/bpf_local_storage.c                | 190 +++++++++-----
 kernel/bpf/bpf_task_storage.c                 |  38 +--
 kernel/bpf/cgroup_iter.c                      |   2 +-
 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 +
 net/core/bpf_sk_storage.c                     |  35 +--
 scripts/bpf_doc.py                            |   2 +
 .../bpf/bpftool/Documentation/bpftool-map.rst |   2 +-
 tools/bpf/bpftool/map.c                       |   2 +-
 tools/include/uapi/linux/bpf.h                |  50 +++-
 tools/lib/bpf/libbpf.c                        |   1 +
 tools/lib/bpf/libbpf_probes.c                 |   1 +
 tools/testing/selftests/bpf/DENYLIST.s390x    |   1 +
 .../bpf/prog_tests/cgrp_local_storage.c       | 171 ++++++++++++
 .../selftests/bpf/prog_tests/libbpf_str.c     |   8 +
 .../bpf/progs/cgrp_ls_attach_cgroup.c         | 101 +++++++
 .../selftests/bpf/progs/cgrp_ls_negative.c    |  26 ++
 .../selftests/bpf/progs/cgrp_ls_recursion.c   |  70 +++++
 .../selftests/bpf/progs/cgrp_ls_tp_btf.c      |  88 +++++++
 32 files changed, 1102 insertions(+), 189 deletions(-)
 create mode 100644 Documentation/bpf/map_cgrp_storage.rst
 create mode 100644 kernel/bpf/bpf_cgrp_storage.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_negative.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_tp_btf.c

-- 
2.30.2

[PATCH bpf-next v6 1/9] bpf: Make struct cgroup btf id global

[Yonghong Song]

Make struct cgroup btf id global so later patch can reuse
the same btf id.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/btf_ids.h  | 1 +
 kernel/bpf/cgroup_iter.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 2aea877d644f..c9744efd202f 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -265,5 +265,6 @@ MAX_BTF_TRACING_TYPE,
 };
 
 extern u32 btf_tracing_ids[];
+extern u32 bpf_cgroup_btf_id[];
 
 #endif
diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c
index 0d200a993489..c6ffc706d583 100644
--- a/kernel/bpf/cgroup_iter.c
+++ b/kernel/bpf/cgroup_iter.c
@@ -157,7 +157,7 @@ static const struct seq_operations cgroup_iter_seq_ops = {
 	.show   = cgroup_iter_seq_show,
 };
 
-BTF_ID_LIST_SINGLE(bpf_cgroup_btf_id, struct, cgroup)
+BTF_ID_LIST_GLOBAL_SINGLE(bpf_cgroup_btf_id, struct, cgroup)
 
 static int cgroup_iter_seq_init(void *priv, struct bpf_iter_aux_info *aux)
 {
-- 
2.30.2

[PATCH bpf-next v6 2/9] bpf: Refactor some inode/task/sk storage functions for reuse

[Yonghong Song]

Refactor codes so that inode/task/sk storage implementation
can maximally share the same code. I also added some comments
in new function bpf_local_storage_unlink_nolock() to make
codes easy to understand. There is no functionality change.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf_local_storage.h |  17 ++-
 kernel/bpf/bpf_inode_storage.c    |  38 +-----
 kernel/bpf/bpf_local_storage.c    | 190 +++++++++++++++++++-----------
 kernel/bpf/bpf_task_storage.c     |  38 +-----
 net/core/bpf_sk_storage.c         |  35 +-----
 5 files changed, 137 insertions(+), 181 deletions(-)

diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 7ea18d4da84b..6d37a40cd90e 100644
--- a/include/linux/bpf_local_storage.h
+++ b/include/linux/bpf_local_storage.h
@@ -116,21 +116,22 @@ static struct bpf_local_storage_cache name = {			\
 	.idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock),	\
 }
 
-u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache);
-void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
-				      u16 idx);
-
 /* Helper functions for bpf_local_storage */
 int bpf_local_storage_map_alloc_check(union bpf_attr *attr);
 
-struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr);
+struct bpf_map *
+bpf_local_storage_map_alloc(union bpf_attr *attr,
+			    struct bpf_local_storage_cache *cache);
 
 struct bpf_local_storage_data *
 bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
 			 struct bpf_local_storage_map *smap,
 			 bool cacheit_lockit);
 
-void bpf_local_storage_map_free(struct bpf_local_storage_map *smap,
+bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage);
+
+void bpf_local_storage_map_free(struct bpf_map *map,
+				struct bpf_local_storage_cache *cache,
 				int __percpu *busy_counter);
 
 int bpf_local_storage_map_check_btf(const struct bpf_map *map,
@@ -141,10 +142,6 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map,
 void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage,
 				   struct bpf_local_storage_elem *selem);
 
-bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
-				     struct bpf_local_storage_elem *selem,
-				     bool uncharge_omem, bool use_trace_rcu);
-
 void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu);
 
 void bpf_selem_link_map(struct bpf_local_storage_map *smap,
diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c
index 5f7683b19199..6a1d4d22816a 100644
--- a/kernel/bpf/bpf_inode_storage.c
+++ b/kernel/bpf/bpf_inode_storage.c
@@ -56,11 +56,9 @@ static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
 
 void bpf_inode_storage_free(struct inode *inode)
 {
-	struct bpf_local_storage_elem *selem;
 	struct bpf_local_storage *local_storage;
 	bool free_inode_storage = false;
 	struct bpf_storage_blob *bsb;
-	struct hlist_node *n;
 
 	bsb = bpf_inode(inode);
 	if (!bsb)
@@ -74,30 +72,11 @@ void bpf_inode_storage_free(struct inode *inode)
 		return;
 	}
 
-	/* Neither the bpf_prog nor the bpf-map's syscall
-	 * could be modifying the local_storage->list now.
-	 * Thus, no elem can be added-to or deleted-from the
-	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
-	 *
-	 * It is racing with bpf_local_storage_map_free() alone
-	 * when unlinking elem from the local_storage->list and
-	 * the map's bucket->list.
-	 */
 	raw_spin_lock_bh(&local_storage->lock);
-	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
-		/* Always unlink from map before unlinking from
-		 * local_storage.
-		 */
-		bpf_selem_unlink_map(selem);
-		free_inode_storage = bpf_selem_unlink_storage_nolock(
-			local_storage, selem, false, false);
-	}
+	free_inode_storage = bpf_local_storage_unlink_nolock(local_storage);
 	raw_spin_unlock_bh(&local_storage->lock);
 	rcu_read_unlock();
 
-	/* free_inoode_storage should always be true as long as
-	 * local_storage->list was non-empty.
-	 */
 	if (free_inode_storage)
 		kfree_rcu(local_storage, rcu);
 }
@@ -226,23 +205,12 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key,
 
 static struct bpf_map *inode_storage_map_alloc(union bpf_attr *attr)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = bpf_local_storage_map_alloc(attr);
-	if (IS_ERR(smap))
-		return ERR_CAST(smap);
-
-	smap->cache_idx = bpf_local_storage_cache_idx_get(&inode_cache);
-	return &smap->map;
+	return bpf_local_storage_map_alloc(attr, &inode_cache);
 }
 
 static void inode_storage_map_free(struct bpf_map *map)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = (struct bpf_local_storage_map *)map;
-	bpf_local_storage_cache_idx_free(&inode_cache, smap->cache_idx);
-	bpf_local_storage_map_free(smap, NULL);
+	bpf_local_storage_map_free(map, &inode_cache, NULL);
 }
 
 BTF_ID_LIST_SINGLE(inode_storage_map_btf_ids, struct,
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 9dc6de1cf185..108aa17b9a7a 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -113,9 +113,9 @@ static void bpf_selem_free_rcu(struct rcu_head *rcu)
  * The caller must ensure selem->smap is still valid to be
  * dereferenced for its smap->elem_size and smap->cache_idx.
  */
-bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
-				     struct bpf_local_storage_elem *selem,
-				     bool uncharge_mem, bool use_trace_rcu)
+static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage,
+					    struct bpf_local_storage_elem *selem,
+					    bool uncharge_mem, bool use_trace_rcu)
 {
 	struct bpf_local_storage_map *smap;
 	bool free_local_storage;
@@ -500,7 +500,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap,
 	return ERR_PTR(err);
 }
 
-u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
+static u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
 {
 	u64 min_usage = U64_MAX;
 	u16 i, res = 0;
@@ -524,76 +524,14 @@ u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
 	return res;
 }
 
-void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
-				      u16 idx)
+static void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+					     u16 idx)
 {
 	spin_lock(&cache->idx_lock);
 	cache->idx_usage_counts[idx]--;
 	spin_unlock(&cache->idx_lock);
 }
 
-void bpf_local_storage_map_free(struct bpf_local_storage_map *smap,
-				int __percpu *busy_counter)
-{
-	struct bpf_local_storage_elem *selem;
-	struct bpf_local_storage_map_bucket *b;
-	unsigned int i;
-
-	/* Note that this map might be concurrently cloned from
-	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
-	 * RCU read section to finish before proceeding. New RCU
-	 * read sections should be prevented via bpf_map_inc_not_zero.
-	 */
-	synchronize_rcu();
-
-	/* bpf prog and the userspace can no longer access this map
-	 * now.  No new selem (of this map) can be added
-	 * to the owner->storage or to the map bucket's list.
-	 *
-	 * The elem of this map can be cleaned up here
-	 * or when the storage is freed e.g.
-	 * by bpf_sk_storage_free() during __sk_destruct().
-	 */
-	for (i = 0; i < (1U << smap->bucket_log); i++) {
-		b = &smap->buckets[i];
-
-		rcu_read_lock();
-		/* No one is adding to b->list now */
-		while ((selem = hlist_entry_safe(
-				rcu_dereference_raw(hlist_first_rcu(&b->list)),
-				struct bpf_local_storage_elem, map_node))) {
-			if (busy_counter) {
-				migrate_disable();
-				this_cpu_inc(*busy_counter);
-			}
-			bpf_selem_unlink(selem, false);
-			if (busy_counter) {
-				this_cpu_dec(*busy_counter);
-				migrate_enable();
-			}
-			cond_resched_rcu();
-		}
-		rcu_read_unlock();
-	}
-
-	/* While freeing the storage we may still need to access the map.
-	 *
-	 * e.g. when bpf_sk_storage_free() has unlinked selem from the map
-	 * which then made the above while((selem = ...)) loop
-	 * exit immediately.
-	 *
-	 * However, while freeing the storage one still needs to access the
-	 * smap->elem_size to do the uncharging in
-	 * bpf_selem_unlink_storage_nolock().
-	 *
-	 * Hence, wait another rcu grace period for the storage to be freed.
-	 */
-	synchronize_rcu();
-
-	kvfree(smap->buckets);
-	bpf_map_area_free(smap);
-}
-
 int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
 {
 	if (attr->map_flags & ~BPF_LOCAL_STORAGE_CREATE_FLAG_MASK ||
@@ -613,7 +551,7 @@ int bpf_local_storage_map_alloc_check(union bpf_attr *attr)
 	return 0;
 }
 
-struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
+static struct bpf_local_storage_map *__bpf_local_storage_map_alloc(union bpf_attr *attr)
 {
 	struct bpf_local_storage_map *smap;
 	unsigned int i;
@@ -663,3 +601,117 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map,
 
 	return 0;
 }
+
+bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage)
+{
+	struct bpf_local_storage_elem *selem;
+	bool free_storage = false;
+	struct hlist_node *n;
+
+	/* Neither the bpf_prog nor the bpf_map's syscall
+	 * could be modifying the local_storage->list now.
+	 * Thus, no elem can be added to or deleted from the
+	 * local_storage->list by the bpf_prog or by the bpf_map's syscall.
+	 *
+	 * It is racing with bpf_local_storage_map_free() alone
+	 * when unlinking elem from the local_storage->list and
+	 * the map's bucket->list.
+	 */
+	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
+		/* Always unlink from map before unlinking from
+		 * local_storage.
+		 */
+		bpf_selem_unlink_map(selem);
+		/* If local_storage list has only one element, the
+		 * bpf_selem_unlink_storage_nolock() will return true.
+		 * Otherwise, it will return false. The current loop iteration
+		 * intends to remove all local storage. So the last iteration
+		 * of the loop will set the free_cgroup_storage to true.
+		 */
+		free_storage = bpf_selem_unlink_storage_nolock(
+			local_storage, selem, false, false);
+	}
+
+	return free_storage;
+}
+
+struct bpf_map *
+bpf_local_storage_map_alloc(union bpf_attr *attr,
+			    struct bpf_local_storage_cache *cache)
+{
+	struct bpf_local_storage_map *smap;
+
+	smap = __bpf_local_storage_map_alloc(attr);
+	if (IS_ERR(smap))
+		return ERR_CAST(smap);
+
+	smap->cache_idx = bpf_local_storage_cache_idx_get(cache);
+	return &smap->map;
+}
+
+void bpf_local_storage_map_free(struct bpf_map *map,
+				struct bpf_local_storage_cache *cache,
+				int __percpu *busy_counter)
+{
+	struct bpf_local_storage_map_bucket *b;
+	struct bpf_local_storage_elem *selem;
+	struct bpf_local_storage_map *smap;
+	unsigned int i;
+
+	smap = (struct bpf_local_storage_map *)map;
+	bpf_local_storage_cache_idx_free(cache, smap->cache_idx);
+
+	/* Note that this map might be concurrently cloned from
+	 * bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
+	 * RCU read section to finish before proceeding. New RCU
+	 * read sections should be prevented via bpf_map_inc_not_zero.
+	 */
+	synchronize_rcu();
+
+	/* bpf prog and the userspace can no longer access this map
+	 * now.  No new selem (of this map) can be added
+	 * to the owner->storage or to the map bucket's list.
+	 *
+	 * The elem of this map can be cleaned up here
+	 * or when the storage is freed e.g.
+	 * by bpf_sk_storage_free() during __sk_destruct().
+	 */
+	for (i = 0; i < (1U << smap->bucket_log); i++) {
+		b = &smap->buckets[i];
+
+		rcu_read_lock();
+		/* No one is adding to b->list now */
+		while ((selem = hlist_entry_safe(
+				rcu_dereference_raw(hlist_first_rcu(&b->list)),
+				struct bpf_local_storage_elem, map_node))) {
+			if (busy_counter) {
+				migrate_disable();
+				this_cpu_inc(*busy_counter);
+			}
+			bpf_selem_unlink(selem, false);
+			if (busy_counter) {
+				this_cpu_dec(*busy_counter);
+				migrate_enable();
+			}
+			cond_resched_rcu();
+		}
+		rcu_read_unlock();
+	}
+
+	/* While freeing the storage we may still need to access the map.
+	 *
+	 * e.g. when bpf_sk_storage_free() has unlinked selem from the map
+	 * which then made the above while((selem = ...)) loop
+	 * exit immediately.
+	 *
+	 * However, while freeing the storage one still needs to access the
+	 * smap->elem_size to do the uncharging in
+	 * bpf_selem_unlink_storage_nolock().
+	 *
+	 * Hence, wait another rcu grace period for the storage to be freed.
+	 */
+	synchronize_rcu();
+
+	kvfree(smap->buckets);
+	bpf_map_area_free(smap);
+}
diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c
index 6f290623347e..40a92edd6f53 100644
--- a/kernel/bpf/bpf_task_storage.c
+++ b/kernel/bpf/bpf_task_storage.c
@@ -71,10 +71,8 @@ task_storage_lookup(struct task_struct *task, struct bpf_map *map,
 
 void bpf_task_storage_free(struct task_struct *task)
 {
-	struct bpf_local_storage_elem *selem;
 	struct bpf_local_storage *local_storage;
 	bool free_task_storage = false;
-	struct hlist_node *n;
 	unsigned long flags;
 
 	rcu_read_lock();
@@ -85,32 +83,13 @@ void bpf_task_storage_free(struct task_struct *task)
 		return;
 	}
 
-	/* Neither the bpf_prog nor the bpf-map's syscall
-	 * could be modifying the local_storage->list now.
-	 * Thus, no elem can be added-to or deleted-from the
-	 * local_storage->list by the bpf_prog or by the bpf-map's syscall.
-	 *
-	 * It is racing with bpf_local_storage_map_free() alone
-	 * when unlinking elem from the local_storage->list and
-	 * the map's bucket->list.
-	 */
 	bpf_task_storage_lock();
 	raw_spin_lock_irqsave(&local_storage->lock, flags);
-	hlist_for_each_entry_safe(selem, n, &local_storage->list, snode) {
-		/* Always unlink from map before unlinking from
-		 * local_storage.
-		 */
-		bpf_selem_unlink_map(selem);
-		free_task_storage = bpf_selem_unlink_storage_nolock(
-			local_storage, selem, false, false);
-	}
+	free_task_storage = bpf_local_storage_unlink_nolock(local_storage);
 	raw_spin_unlock_irqrestore(&local_storage->lock, flags);
 	bpf_task_storage_unlock();
 	rcu_read_unlock();
 
-	/* free_task_storage should always be true as long as
-	 * local_storage->list was non-empty.
-	 */
 	if (free_task_storage)
 		kfree_rcu(local_storage, rcu);
 }
@@ -288,23 +267,12 @@ static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key)
 
 static struct bpf_map *task_storage_map_alloc(union bpf_attr *attr)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = bpf_local_storage_map_alloc(attr);
-	if (IS_ERR(smap))
-		return ERR_CAST(smap);
-
-	smap->cache_idx = bpf_local_storage_cache_idx_get(&task_cache);
-	return &smap->map;
+	return bpf_local_storage_map_alloc(attr, &task_cache);
 }
 
 static void task_storage_map_free(struct bpf_map *map)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = (struct bpf_local_storage_map *)map;
-	bpf_local_storage_cache_idx_free(&task_cache, smap->cache_idx);
-	bpf_local_storage_map_free(smap, &bpf_task_storage_busy);
+	bpf_local_storage_map_free(map, &task_cache, &bpf_task_storage_busy);
 }
 
 BTF_ID_LIST_SINGLE(task_storage_map_btf_ids, struct, bpf_local_storage_map)
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 94374d529ea4..49884e7de080 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -48,10 +48,8 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map)
 /* Called by __sk_destruct() & bpf_sk_storage_clone() */
 void bpf_sk_storage_free(struct sock *sk)
 {
-	struct bpf_local_storage_elem *selem;
 	struct bpf_local_storage *sk_storage;
 	bool free_sk_storage = false;
-	struct hlist_node *n;
 
 	rcu_read_lock();
 	sk_storage = rcu_dereference(sk->sk_bpf_storage);
@@ -60,24 +58,8 @@ void bpf_sk_storage_free(struct sock *sk)
 		return;
 	}
 
-	/* Netiher the bpf_prog nor the bpf-map's syscall
-	 * could be modifying the sk_storage->list now.
-	 * Thus, no elem can be added-to or deleted-from the
-	 * sk_storage->list by the bpf_prog or by the bpf-map's syscall.
-	 *
-	 * It is racing with bpf_local_storage_map_free() alone
-	 * when unlinking elem from the sk_storage->list and
-	 * the map's bucket->list.
-	 */
 	raw_spin_lock_bh(&sk_storage->lock);
-	hlist_for_each_entry_safe(selem, n, &sk_storage->list, snode) {
-		/* Always unlink from map before unlinking from
-		 * sk_storage.
-		 */
-		bpf_selem_unlink_map(selem);
-		free_sk_storage = bpf_selem_unlink_storage_nolock(
-			sk_storage, selem, true, false);
-	}
+	free_sk_storage = bpf_local_storage_unlink_nolock(sk_storage);
 	raw_spin_unlock_bh(&sk_storage->lock);
 	rcu_read_unlock();
 
@@ -87,23 +69,12 @@ void bpf_sk_storage_free(struct sock *sk)
 
 static void bpf_sk_storage_map_free(struct bpf_map *map)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = (struct bpf_local_storage_map *)map;
-	bpf_local_storage_cache_idx_free(&sk_cache, smap->cache_idx);
-	bpf_local_storage_map_free(smap, NULL);
+	bpf_local_storage_map_free(map, &sk_cache, NULL);
 }
 
 static struct bpf_map *bpf_sk_storage_map_alloc(union bpf_attr *attr)
 {
-	struct bpf_local_storage_map *smap;
-
-	smap = bpf_local_storage_map_alloc(attr);
-	if (IS_ERR(smap))
-		return ERR_CAST(smap);
-
-	smap->cache_idx = bpf_local_storage_cache_idx_get(&sk_cache);
-	return &smap->map;
+	return bpf_local_storage_map_alloc(attr, &sk_cache);
 }
 
 static int notsupp_get_next_key(struct bpf_map *map, void *key,
-- 
2.30.2

[PATCH bpf-next v6 3/9] bpf: Implement cgroup storage available to non-cgroup-attached bpf progs

[Yonghong Song]

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>
---
 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);
+	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

[PATCH bpf-next v6 4/9] libbpf: Support new cgroup local storage

[Yonghong Song]

Add support for new cgroup local storage.

Acked-by: David Vernet <void@manifault.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/lib/bpf/libbpf.c        | 1 +
 tools/lib/bpf/libbpf_probes.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 027fd9565c16..5d7819edf074 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -164,6 +164,7 @@ static const char * const map_type_name[] = {
 	[BPF_MAP_TYPE_TASK_STORAGE]		= "task_storage",
 	[BPF_MAP_TYPE_BLOOM_FILTER]		= "bloom_filter",
 	[BPF_MAP_TYPE_USER_RINGBUF]             = "user_ringbuf",
+	[BPF_MAP_TYPE_CGRP_STORAGE]		= "cgrp_storage",
 };
 
 static const char * const prog_type_name[] = {
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index f3a8e8e74eb8..bdb83d467f9a 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -221,6 +221,7 @@ static int probe_map_create(enum bpf_map_type map_type)
 	case BPF_MAP_TYPE_SK_STORAGE:
 	case BPF_MAP_TYPE_INODE_STORAGE:
 	case BPF_MAP_TYPE_TASK_STORAGE:
+	case BPF_MAP_TYPE_CGRP_STORAGE:
 		btf_key_type_id = 1;
 		btf_value_type_id = 3;
 		value_size = 8;
-- 
2.30.2

[PATCH bpf-next v6 5/9] bpftool: Support new cgroup local storage

[Yonghong Song]

Add support for new cgroup local storage

Acked-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/bpf/bpftool/Documentation/bpftool-map.rst | 2 +-
 tools/bpf/bpftool/map.c                         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index 7f3b67a8b48f..11250c4734fe 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
@@ -55,7 +55,7 @@ MAP COMMANDS
 |		| **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash**
 |		| **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage**
 |		| **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage**
-|		| **task_storage** | **bloom_filter** | **user_ringbuf** }
+|		| **task_storage** | **bloom_filter** | **user_ringbuf** | **cgrp_storage** }
 
 DESCRIPTION
 ===========
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 3087ced658ad..f941ac5c7b73 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1458,7 +1458,7 @@ static int do_help(int argc, char **argv)
 		"                 devmap | devmap_hash | sockmap | cpumap | xskmap | sockhash |\n"
 		"                 cgroup_storage | reuseport_sockarray | percpu_cgroup_storage |\n"
 		"                 queue | stack | sk_storage | struct_ops | ringbuf | inode_storage |\n"
-		"                 task_storage | bloom_filter | user_ringbuf }\n"
+		"                 task_storage | bloom_filter | user_ringbuf | cgrp_storage }\n"
 		"       " HELP_SPEC_OPTIONS " |\n"
 		"                    {-f|--bpffs} | {-n|--nomount} }\n"
 		"",
-- 
2.30.2

[PATCH bpf-next v6 6/9] selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str

[Yonghong Song]

Previous bpf patch made a change to uapi bpf.h like
  @@ -922,7 +922,14 @@ enum bpf_map_type {
        BPF_MAP_TYPE_SOCKHASH,
  -     BPF_MAP_TYPE_CGROUP_STORAGE,
  +     BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
  +     BPF_MAP_TYPE_CGROUP_STORAGE = BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
        BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
where BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED and BPF_MAP_TYPE_CGROUP_STORAGE
have the same enum value. This will cause selftest test_libbpf_str/bpf_map_type_str
failing. This patch fixed the issue by avoid the check for
BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED in the test.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/testing/selftests/bpf/prog_tests/libbpf_str.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c
index 93e9cddaadcf..efb8bd43653c 100644
--- a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c
+++ b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c
@@ -139,6 +139,14 @@ static void test_libbpf_bpf_map_type_str(void)
 		snprintf(buf, sizeof(buf), "BPF_MAP_TYPE_%s", map_type_str);
 		uppercase(buf);
 
+		/* Special case for map_type_name BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED
+		 * where it and BPF_MAP_TYPE_CGROUP_STORAGE have the same enum value
+		 * (map_type). For this enum value, libbpf_bpf_map_type_str() picks
+		 * BPF_MAP_TYPE_CGROUP_STORAGE.
+		 */
+		if (strcmp(map_type_name, "BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED") == 0)
+			continue;
+
 		ASSERT_STREQ(buf, map_type_name, "exp_str_value");
 	}
 
-- 
2.30.2

[PATCH bpf-next v6 7/9] selftests/bpf: Add selftests for new cgroup local storage

[Yonghong Song]

Add four tests for new cgroup local storage, (1) testing bpf program helpers
and user space map APIs, (2) testing recursive fentry triggering won't deadlock,
(3) testing progs attached to cgroups, and (4) a negative test if the
bpf_cgrp_storage_get() helper key is not a cgroup btf id.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 .../bpf/prog_tests/cgrp_local_storage.c       | 171 ++++++++++++++++++
 .../bpf/progs/cgrp_ls_attach_cgroup.c         | 101 +++++++++++
 .../selftests/bpf/progs/cgrp_ls_negative.c    |  26 +++
 .../selftests/bpf/progs/cgrp_ls_recursion.c   |  70 +++++++
 .../selftests/bpf/progs/cgrp_ls_tp_btf.c      |  88 +++++++++
 5 files changed, 456 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_negative.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c
 create mode 100644 tools/testing/selftests/bpf/progs/cgrp_ls_tp_btf.c

diff --git a/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c b/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c
new file mode 100644
index 000000000000..1c30412ba132
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cgrp_local_storage.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.*/
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <test_progs.h>
+#include "cgrp_ls_tp_btf.skel.h"
+#include "cgrp_ls_recursion.skel.h"
+#include "cgrp_ls_attach_cgroup.skel.h"
+#include "cgrp_ls_negative.skel.h"
+#include "network_helpers.h"
+
+struct socket_cookie {
+	__u64 cookie_key;
+	__u32 cookie_value;
+};
+
+static void test_tp_btf(int cgroup_fd)
+{
+	struct cgrp_ls_tp_btf *skel;
+	long val1 = 1, val2 = 0;
+	int err;
+
+	skel = cgrp_ls_tp_btf__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	/* populate a value in map_b */
+	err = bpf_map_update_elem(bpf_map__fd(skel->maps.map_b), &cgroup_fd, &val1, BPF_ANY);
+	if (!ASSERT_OK(err, "map_update_elem"))
+		goto out;
+
+	/* check value */
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.map_b), &cgroup_fd, &val2);
+	if (!ASSERT_OK(err, "map_lookup_elem"))
+		goto out;
+	if (!ASSERT_EQ(val2, 1, "map_lookup_elem, invalid val"))
+		goto out;
+
+	/* delete value */
+	err = bpf_map_delete_elem(bpf_map__fd(skel->maps.map_b), &cgroup_fd);
+	if (!ASSERT_OK(err, "map_delete_elem"))
+		goto out;
+
+	skel->bss->target_pid = syscall(SYS_gettid);
+
+	err = cgrp_ls_tp_btf__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto out;
+
+	syscall(SYS_gettid);
+	syscall(SYS_gettid);
+
+	skel->bss->target_pid = 0;
+
+	/* 3x syscalls: 1x attach and 2x gettid */
+	ASSERT_EQ(skel->bss->enter_cnt, 3, "enter_cnt");
+	ASSERT_EQ(skel->bss->exit_cnt, 3, "exit_cnt");
+	ASSERT_EQ(skel->bss->mismatch_cnt, 0, "mismatch_cnt");
+out:
+	cgrp_ls_tp_btf__destroy(skel);
+}
+
+static void test_attach_cgroup(int cgroup_fd)
+{
+	int server_fd = 0, client_fd = 0, err = 0;
+	socklen_t addr_len = sizeof(struct sockaddr_in6);
+	struct cgrp_ls_attach_cgroup *skel;
+	__u32 cookie_expected_value;
+	struct sockaddr_in6 addr;
+	struct socket_cookie val;
+
+	skel = cgrp_ls_attach_cgroup__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return;
+
+	skel->links.set_cookie = bpf_program__attach_cgroup(
+		skel->progs.set_cookie, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.set_cookie, "prog_attach"))
+		goto out;
+
+	skel->links.update_cookie_sockops = bpf_program__attach_cgroup(
+		skel->progs.update_cookie_sockops, cgroup_fd);
+	if (!ASSERT_OK_PTR(skel->links.update_cookie_sockops, "prog_attach"))
+		goto out;
+
+	skel->links.update_cookie_tracing = bpf_program__attach(
+		skel->progs.update_cookie_tracing);
+	if (!ASSERT_OK_PTR(skel->links.update_cookie_tracing, "prog_attach"))
+		goto out;
+
+	server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
+	if (!ASSERT_GE(server_fd, 0, "start_server"))
+		goto out;
+
+	client_fd = connect_to_fd(server_fd, 0);
+	if (!ASSERT_GE(client_fd, 0, "connect_to_fd"))
+		goto close_server_fd;
+
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.socket_cookies),
+				  &cgroup_fd, &val);
+	if (!ASSERT_OK(err, "map_lookup(socket_cookies)"))
+		goto close_client_fd;
+
+	err = getsockname(client_fd, (struct sockaddr *)&addr, &addr_len);
+	if (!ASSERT_OK(err, "getsockname"))
+		goto close_client_fd;
+
+	cookie_expected_value = (ntohs(addr.sin6_port) << 8) | 0xFF;
+	ASSERT_EQ(val.cookie_value, cookie_expected_value, "cookie_value");
+
+close_client_fd:
+	close(client_fd);
+close_server_fd:
+	close(server_fd);
+out:
+	cgrp_ls_attach_cgroup__destroy(skel);
+}
+
+static void test_recursion(int cgroup_fd)
+{
+	struct cgrp_ls_recursion *skel;
+	int err;
+
+	skel = cgrp_ls_recursion__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+		return;
+
+	err = cgrp_ls_recursion__attach(skel);
+	if (!ASSERT_OK(err, "skel_attach"))
+		goto out;
+
+	/* trigger sys_enter, make sure it does not cause deadlock */
+	syscall(SYS_gettid);
+
+out:
+	cgrp_ls_recursion__destroy(skel);
+}
+
+static void test_negative(void)
+{
+	struct cgrp_ls_negative *skel;
+
+	skel = cgrp_ls_negative__open_and_load();
+	if (!ASSERT_ERR_PTR(skel, "skel_open_and_load")) {
+		cgrp_ls_negative__destroy(skel);
+		return;
+	}
+}
+
+void test_cgrp_local_storage(void)
+{
+	int cgroup_fd;
+
+	cgroup_fd = test__join_cgroup("/cgrp_local_storage");
+	if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /cgrp_local_storage"))
+		return;
+
+	if (test__start_subtest("tp_btf"))
+		test_tp_btf(cgroup_fd);
+	if (test__start_subtest("attach_cgroup"))
+		test_attach_cgroup(cgroup_fd);
+	if (test__start_subtest("recursion"))
+		test_recursion(cgroup_fd);
+	if (test__start_subtest("negative"))
+		test_negative();
+
+	close(cgroup_fd);
+}
diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c b/tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c
new file mode 100644
index 000000000000..6652d18465b2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgrp_ls_attach_cgroup.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_tracing_net.h"
+
+char _license[] SEC("license") = "GPL";
+
+struct socket_cookie {
+	__u64 cookie_key;
+	__u64 cookie_value;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, struct socket_cookie);
+} socket_cookies SEC(".maps");
+
+SEC("cgroup/connect6")
+int set_cookie(struct bpf_sock_addr *ctx)
+{
+	struct socket_cookie *p;
+	struct tcp_sock *tcp_sk;
+	struct bpf_sock *sk;
+
+	if (ctx->family != AF_INET6 || ctx->user_family != AF_INET6)
+		return 1;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	tcp_sk = bpf_skc_to_tcp_sock(sk);
+	if (!tcp_sk)
+		return 1;
+
+	p = bpf_cgrp_storage_get(&socket_cookies,
+		tcp_sk->inet_conn.icsk_inet.sk.sk_cgrp_data.cgroup, 0,
+		BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!p)
+		return 1;
+
+	p->cookie_value = 0xF;
+	p->cookie_key = bpf_get_socket_cookie(ctx);
+	return 1;
+}
+
+SEC("sockops")
+int update_cookie_sockops(struct bpf_sock_ops *ctx)
+{
+	struct socket_cookie *p;
+	struct tcp_sock *tcp_sk;
+	struct bpf_sock *sk;
+
+	if (ctx->family != AF_INET6 || ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
+		return 1;
+
+	sk = ctx->sk;
+	if (!sk)
+		return 1;
+
+	tcp_sk = bpf_skc_to_tcp_sock(sk);
+	if (!tcp_sk)
+		return 1;
+
+	p = bpf_cgrp_storage_get(&socket_cookies,
+		tcp_sk->inet_conn.icsk_inet.sk.sk_cgrp_data.cgroup, 0, 0);
+	if (!p)
+		return 1;
+
+	if (p->cookie_key != bpf_get_socket_cookie(ctx))
+		return 1;
+
+	p->cookie_value |= (ctx->local_port << 8);
+	return 1;
+}
+
+SEC("fexit/inet_stream_connect")
+int BPF_PROG(update_cookie_tracing, struct socket *sock,
+	     struct sockaddr *uaddr, int addr_len, int flags)
+{
+	struct socket_cookie *p;
+	struct tcp_sock *tcp_sk;
+
+	if (uaddr->sa_family != AF_INET6)
+		return 0;
+
+	p = bpf_cgrp_storage_get(&socket_cookies, sock->sk->sk_cgrp_data.cgroup, 0, 0);
+	if (!p)
+		return 0;
+
+	if (p->cookie_key != bpf_get_socket_cookie(sock->sk))
+		return 0;
+
+	p->cookie_value |= 0xF0;
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_negative.c b/tools/testing/selftests/bpf/progs/cgrp_ls_negative.c
new file mode 100644
index 000000000000..d41f90e2ab64
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgrp_ls_negative.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_a SEC(".maps");
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+
+	task = bpf_get_current_task_btf();
+	(void)bpf_cgrp_storage_get(&map_a, (struct cgroup *)task, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c
new file mode 100644
index 000000000000..a043d8fefdac
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgrp_ls_recursion.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_a SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_b SEC(".maps");
+
+SEC("fentry/bpf_local_storage_lookup")
+int BPF_PROG(on_lookup)
+{
+	struct task_struct *task = bpf_get_current_task_btf();
+
+	bpf_cgrp_storage_delete(&map_a, task->cgroups->dfl_cgrp);
+	bpf_cgrp_storage_delete(&map_b, task->cgroups->dfl_cgrp);
+	return 0;
+}
+
+SEC("fentry/bpf_local_storage_update")
+int BPF_PROG(on_update)
+{
+	struct task_struct *task = bpf_get_current_task_btf();
+	long *ptr;
+
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr += 1;
+
+	ptr = bpf_cgrp_storage_get(&map_b, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr += 1;
+
+	return 0;
+}
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+
+	task = bpf_get_current_task_btf();
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr = 200;
+
+	ptr = bpf_cgrp_storage_get(&map_b, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (ptr)
+		*ptr = 100;
+	return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/cgrp_ls_tp_btf.c b/tools/testing/selftests/bpf/progs/cgrp_ls_tp_btf.c
new file mode 100644
index 000000000000..9ebb8e2fe541
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgrp_ls_tp_btf.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_a SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, long);
+} map_b SEC(".maps");
+
+#define MAGIC_VALUE 0xabcd1234
+
+pid_t target_pid = 0;
+int mismatch_cnt = 0;
+int enter_cnt = 0;
+int exit_cnt = 0;
+
+SEC("tp_btf/sys_enter")
+int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+	int err;
+
+	task = bpf_get_current_task_btf();
+	if (task->pid != target_pid)
+		return 0;
+
+	/* populate value 0 */
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+
+	/* delete value 0 */
+	err = bpf_cgrp_storage_delete(&map_a, task->cgroups->dfl_cgrp);
+	if (err)
+		return 0;
+
+	/* value is not available */
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0, 0);
+	if (ptr)
+		return 0;
+
+	/* re-populate the value */
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+	__sync_fetch_and_add(&enter_cnt, 1);
+	*ptr = MAGIC_VALUE + enter_cnt;
+
+	return 0;
+}
+
+SEC("tp_btf/sys_exit")
+int BPF_PROG(on_exit, struct pt_regs *regs, long id)
+{
+	struct task_struct *task;
+	long *ptr;
+
+	task = bpf_get_current_task_btf();
+	if (task->pid != target_pid)
+		return 0;
+
+	ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
+				   BPF_LOCAL_STORAGE_GET_F_CREATE);
+	if (!ptr)
+		return 0;
+
+	__sync_fetch_and_add(&exit_cnt, 1);
+	if (*ptr != MAGIC_VALUE + exit_cnt)
+		__sync_fetch_and_add(&mismatch_cnt, 1);
+	return 0;
+}
-- 
2.30.2

[PATCH bpf-next v6 8/9] selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x

[Yonghong Song]

Test cgrp_local_storage have some programs utilizing trampoline.
Arch s390x does not support trampoline so add the test to
the corresponding DENYLIST file.

Signed-off-by: Yonghong Song <yhs@fb.com>
---
 tools/testing/selftests/bpf/DENYLIST.s390x | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index 520f12229b98..be4e3d47ea3e 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -10,6 +10,7 @@ bpf_nf                                   # JIT does not support calling kernel f
 bpf_tcp_ca                               # JIT does not support calling kernel function                                (kfunc)
 cb_refs                                  # expected error message unexpected error: -524                               (trampoline)
 cgroup_hierarchical_stats                # JIT does not support calling kernel function                                (kfunc)
+cgrp_local_storage                       # prog_attach unexpected error: -524                                          (trampoline)
 core_read_macros                         # unknown func bpf_probe_read#4                                               (overlapping)
 d_path                                   # failed to auto-attach program 'prog_stat': -524                             (trampoline)
 deny_namespace                           # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
-- 
2.30.2

[PATCH bpf-next v6 9/9] docs/bpf: Add documentation for new cgroup local storage

[Yonghong Song]

Add some descriptions and examples for BPF_MAP_TYPE_CGRP_STORAGE.
Also illustate the major difference between BPF_MAP_TYPE_CGRP_STORAGE
and BPF_MAP_TYPE_CGROUP_STORAGE and recommend to use
BPF_MAP_TYPE_CGRP_STORAGE instead of BPF_MAP_TYPE_CGROUP_STORAGE
in the end.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 Documentation/bpf/map_cgrp_storage.rst | 109 +++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 Documentation/bpf/map_cgrp_storage.rst

diff --git a/Documentation/bpf/map_cgrp_storage.rst b/Documentation/bpf/map_cgrp_storage.rst
new file mode 100644
index 000000000000..5d3f603efffa
--- /dev/null
+++ b/Documentation/bpf/map_cgrp_storage.rst
@@ -0,0 +1,109 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+.. Copyright (C) 2022 Meta Platforms, Inc. and affiliates.
+
+=========================
+BPF_MAP_TYPE_CGRP_STORAGE
+=========================
+
+The ``BPF_MAP_TYPE_CGRP_STORAGE`` map type represents a local fix-sized
+storage for cgroups. It is only available with ``CONFIG_CGROUPS``.
+The programs are made available by the same Kconfig. The
+data for a particular cgroup can be retrieved by looking up the map
+with that cgroup.
+
+This document describes the usage and semantics of the
+``BPF_MAP_TYPE_CGRP_STORAGE`` map type.
+
+Usage
+=====
+
+The map key must be ``sizeof(int)`` representing a cgroup fd.
+To access the storage in a program, use ``bpf_cgrp_storage_get``::
+
+    void *bpf_cgrp_storage_get(struct bpf_map *map, struct cgroup *cgroup, void *value, u64 flags)
+
+``flags`` could be 0 or ``BPF_LOCAL_STORAGE_GET_F_CREATE`` which indicates that
+a new local storage will be created if one does not exist.
+
+The local storage can be removed with ``bpf_cgrp_storage_delete``::
+
+    long bpf_cgrp_storage_delete(struct bpf_map *map, struct cgroup *cgroup)
+
+The map is available to all program types.
+
+Examples
+========
+
+A BPF program example with BPF_MAP_TYPE_CGRP_STORAGE::
+
+    #include <vmlinux.h>
+    #include <bpf/bpf_helpers.h>
+    #include <bpf/bpf_tracing.h>
+
+    struct {
+            __uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
+            __uint(map_flags, BPF_F_NO_PREALLOC);
+            __type(key, int);
+            __type(value, long);
+    } cgrp_storage SEC(".maps");
+
+    SEC("tp_btf/sys_enter")
+    int BPF_PROG(on_enter, struct pt_regs *regs, long id)
+    {
+            struct task_struct *task = bpf_get_current_task_btf();
+            long *ptr;
+
+            ptr = bpf_cgrp_storage_get(&cgrp_storage, task->cgroups->dfl_cgrp, 0,
+                                       BPF_LOCAL_STORAGE_GET_F_CREATE);
+            if (ptr)
+                __sync_fetch_and_add(ptr, 1);
+
+            return 0;
+    }
+
+Userspace accessing map declared above::
+
+    #include <linux/bpf.h>
+    #include <linux/libbpf.h>
+
+    __u32 map_lookup(struct bpf_map *map, int cgrp_fd)
+    {
+            __u32 *value;
+            value = bpf_map_lookup_elem(bpf_map__fd(map), &cgrp_fd);
+            if (value)
+                return *value;
+            return 0;
+    }
+
+Difference Between BPF_MAP_TYPE_CGRP_STORAGE and BPF_MAP_TYPE_CGROUP_STORAGE
+============================================================================
+
+The old cgroup storage map ``BPF_MAP_TYPE_CGROUP_STORAGE`` has been marked as
+deprecated (renamed to ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED``). The new
+``BPF_MAP_TYPE_CGRP_STORAGE`` map should be used instead. The following
+illusates the main difference between ``BPF_MAP_TYPE_CGRP_STORAGE`` and
+``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED``.
+
+(1). ``BPF_MAP_TYPE_CGRP_STORAGE`` can be used by all program types while
+     ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED`` is available only to cgroup program types
+     like BPF_CGROUP_INET_INGRESS or BPF_CGROUP_SOCK_OPS, etc.
+
+(2). ``BPF_MAP_TYPE_CGRP_STORAGE`` supports local storage for more than one
+     cgroup while ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED`` only supports one cgroup
+     which is attached by a BPF program.
+
+(3). ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED`` allocates local storage at attach time so
+     ``bpf_get_local_storage()`` always returns non-NULL local storage.
+     ``BPF_MAP_TYPE_CGRP_STORAGE`` allocates local storage at runtime so
+     it is possible that ``bpf_cgrp_storage_get()`` may return null local storage.
+     To avoid such null local storage issue, user space can do
+     ``bpf_map_update_elem()`` to pre-allocate local storage before a BPF program
+     is attached.
+
+(4). ``BPF_MAP_TYPE_CGRP_STORAGE`` supports deleting local storage by a BPF program
+     while ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED`` only deletes storage during
+     prog detach time.
+
+So overall, ``BPF_MAP_TYPE_CGRP_STORAGE`` supports all ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED``
+functionality and beyond. It is recommended to use ``BPF_MAP_TYPE_CGRP_STORAGE``
+instead of ``BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED``.
-- 
2.30.2

Re: [PATCH bpf-next v6 0/9] bpf: Implement cgroup local storage available to non-cgroup-attached bpf progs

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Tue, 25 Oct 2022 21:28:35 -0700 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v6,1/9] bpf: Make struct cgroup btf id global
    https://git.kernel.org/bpf/bpf-next/c/5e67b8ef125b
  - [bpf-next,v6,2/9] bpf: Refactor some inode/task/sk storage functions for reuse
    https://git.kernel.org/bpf/bpf-next/c/c83597fa5dc6
  - [bpf-next,v6,3/9] bpf: Implement cgroup storage available to non-cgroup-attached bpf progs
    https://git.kernel.org/bpf/bpf-next/c/c4bcfb38a95e
  - [bpf-next,v6,4/9] libbpf: Support new cgroup local storage
    https://git.kernel.org/bpf/bpf-next/c/4fe64af23c12
  - [bpf-next,v6,5/9] bpftool: Support new cgroup local storage
    https://git.kernel.org/bpf/bpf-next/c/f7f0f1657d95
  - [bpf-next,v6,6/9] selftests/bpf: Fix test test_libbpf_str/bpf_map_type_str
    https://git.kernel.org/bpf/bpf-next/c/fd4ca6c1facf
  - [bpf-next,v6,7/9] selftests/bpf: Add selftests for new cgroup local storage
    https://git.kernel.org/bpf/bpf-next/c/12bb6ca4e2fa
  - [bpf-next,v6,8/9] selftests/bpf: Add test cgrp_local_storage to DENYLIST.s390x
    https://git.kernel.org/bpf/bpf-next/c/0a1b69d1c736
  - [bpf-next,v6,9/9] docs/bpf: Add documentation for new cgroup local storage
    https://git.kernel.org/bpf/bpf-next/c/d43198017ea3

You are awesome, thank you!
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