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bpf: Refactor codes into bpf_local_storage_destroy

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This patch first renames bpf_local_storage_unlink_nolock to
bpf_local_storage_destroy(). It better reflects that it is only
used when the storage's owner (sk/task/cgrp/inode) is being kfree().

All bpf_local_storage_destroy's caller is taking the spin lock and
then free the storage. This patch also moves these two steps into
the bpf_local_storage_destroy.

This is a preparation work for a later patch that uses
bpf_mem_cache_alloc/free in the bpf_local_storage.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Martin KaFai Lau 2023-03-07 22:59:21 -08:00 committed by Alexei Starovoitov
parent 4cbd23cc92
commit 2ffcb6fc50
6 changed files with 11 additions and 33 deletions
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2
include/linux/bpf_local_storage.h
View File

@ -128,7 +128,7 @@ bpf_local_storage_lookup(struct bpf_local_storage *local_storage,
struct bpf_local_storage_map *smap,
bool cacheit_lockit);
bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage);
void bpf_local_storage_destroy(struct bpf_local_storage *local_storage);
void bpf_local_storage_map_free(struct bpf_map *map,
struct bpf_local_storage_cache *cache,

9
kernel/bpf/bpf_cgrp_storage.c
View File

@ -46,8 +46,6 @@ static struct bpf_local_storage __rcu **cgroup_storage_ptr(void *owner)
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);
@ -57,14 +55,9 @@ void bpf_cgrp_storage_free(struct cgroup *cgroup)
}
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_local_storage_destroy(local_storage);
bpf_cgrp_storage_unlock();
rcu_read_unlock();
if (free_cgroup_storage)
kfree_rcu(local_storage, rcu);
}
static struct bpf_local_storage_data *

8
kernel/bpf/bpf_inode_storage.c
View File

@ -57,7 +57,6 @@ static struct bpf_local_storage_data *inode_storage_lookup(struct inode *inode,
void bpf_inode_storage_free(struct inode *inode)
{
struct bpf_local_storage *local_storage;
bool free_inode_storage = false;
struct bpf_storage_blob *bsb;
bsb = bpf_inode(inode);
@ -72,13 +71,8 @@ void bpf_inode_storage_free(struct inode *inode)
return;
}
raw_spin_lock_bh(&local_storage->lock);
free_inode_storage = bpf_local_storage_unlink_nolock(local_storage);
raw_spin_unlock_bh(&local_storage->lock);
bpf_local_storage_destroy(local_storage);
rcu_read_unlock();
if (free_inode_storage)
kfree_rcu(local_storage, rcu);
}
static void *bpf_fd_inode_storage_lookup_elem(struct bpf_map *map, void *key)

8
kernel/bpf/bpf_local_storage.c
View File

@ -652,11 +652,12 @@ 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)
void bpf_local_storage_destroy(struct bpf_local_storage *local_storage)
{
struct bpf_local_storage_elem *selem;
bool free_storage = false;
struct hlist_node *n;
unsigned long flags;
/* Neither the bpf_prog nor the bpf_map's syscall
* could be modifying the local_storage->list now.
@ -667,6 +668,7 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage)
* when unlinking elem from the local_storage->list and
* the map's bucket->list.
*/
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.
@ -681,8 +683,10 @@ bool bpf_local_storage_unlink_nolock(struct bpf_local_storage *local_storage)
free_storage = bpf_selem_unlink_storage_nolock(
local_storage, selem, false, false);
}
raw_spin_unlock_irqrestore(&local_storage->lock, flags);
return free_storage;
if (free_storage)
kfree_rcu(local_storage, rcu);
}
u64 bpf_local_storage_map_mem_usage(const struct bpf_map *map)

9
kernel/bpf/bpf_task_storage.c
View File

@ -72,8 +72,6 @@ task_storage_lookup(struct task_struct *task, struct bpf_map *map,
void bpf_task_storage_free(struct task_struct *task)
{
struct bpf_local_storage *local_storage;
bool free_task_storage = false;
unsigned long flags;
rcu_read_lock();
@ -84,14 +82,9 @@ void bpf_task_storage_free(struct task_struct *task)
}
bpf_task_storage_lock();
raw_spin_lock_irqsave(&local_storage->lock, flags);
free_task_storage = bpf_local_storage_unlink_nolock(local_storage);
raw_spin_unlock_irqrestore(&local_storage->lock, flags);
bpf_local_storage_destroy(local_storage);
bpf_task_storage_unlock();
rcu_read_unlock();
if (free_task_storage)
kfree_rcu(local_storage, rcu);
}
static void *bpf_pid_task_storage_lookup_elem(struct bpf_map *map, void *key)

8
net/core/bpf_sk_storage.c
View File

@ -49,7 +49,6 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map)
void bpf_sk_storage_free(struct sock *sk)
{
struct bpf_local_storage *sk_storage;
bool free_sk_storage = false;
rcu_read_lock();
sk_storage = rcu_dereference(sk->sk_bpf_storage);
@ -58,13 +57,8 @@ void bpf_sk_storage_free(struct sock *sk)
return;
}
raw_spin_lock_bh(&sk_storage->lock);
free_sk_storage = bpf_local_storage_unlink_nolock(sk_storage);
raw_spin_unlock_bh(&sk_storage->lock);
bpf_local_storage_destroy(sk_storage);
rcu_read_unlock();
if (free_sk_storage)
kfree_rcu(sk_storage, rcu);
}
static void bpf_sk_storage_map_free(struct bpf_map *map)