This is a note to let you know that I've just added the patch titled
bpf: Refactor some inode/task/sk storage functions for reuse
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-refactor-some-inode-task-sk-storage-functions-fo.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b243ffd1225efb6fbb28431fe18afb6657e01725
Author: Yonghong Song <yhs@xxxxxx>
Date: Tue Oct 25 21:28:45 2022 -0700
bpf: Refactor some inode/task/sk storage functions for reuse
[ Upstream commit c83597fa5dc6b322e9bdf929e5f4136a3f4aa4db ]
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@xxxxxxxxxxxxx>
Signed-off-by: Yonghong Song <yhs@xxxxxx>
Link: https://lore.kernel.org/r/20221026042845.672944-1-yhs@xxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Stable-dep-of: af253aef183a ("bpf: fix order of args in call to bpf_map_kvcalloc")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h
index 7ea18d4da84b8..6d37a40cd90e8 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 5f7683b191998..6a1d4d22816a3 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 d9d88a2cda5e5..b1090a2b02b34 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -114,9 +114,9 @@ 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;
@@ -501,7 +501,7 @@ 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;
@@ -525,76 +525,14 @@ 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 ||
@@ -614,7 +552,7 @@ 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;
@@ -664,3 +602,117 @@ 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 6f290623347e0..40a92edd6f539 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 ad01b1bea52e4..0124536e8a9db 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,
