To prepare changing both bpf_local_storage_map_bucket::lock and bpf_local_storage::lock to rqspinlock, convert bpf_selem_unlink() to failable. It still always succeeds and returns 0 until the change happens. No functional change. For bpf_local_storage_map_free(), since it cannot deadlock with itself or bpf_local_storage_destroy who the function might be racing with, retry if bpf_selem_unlink() fails due to rqspinlock returning errors. __must_check is added to the function declaration locally to make sure all callers are accounted for during the conversion. Signed-off-by: Amery Hung --- include/linux/bpf_local_storage.h | 2 +- kernel/bpf/bpf_cgrp_storage.c | 3 +-- kernel/bpf/bpf_inode_storage.c | 4 +--- kernel/bpf/bpf_local_storage.c | 6 ++++-- kernel/bpf/bpf_task_storage.c | 4 +--- net/core/bpf_sk_storage.c | 4 +--- 6 files changed, 9 insertions(+), 14 deletions(-) diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h index dc56fa459ac9..26b7f53dad33 100644 --- a/include/linux/bpf_local_storage.h +++ b/include/linux/bpf_local_storage.h @@ -180,7 +180,7 @@ 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); -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); int bpf_selem_link_map(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem *selem); diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c index 0687a760974a..8fef24fcac68 100644 --- a/kernel/bpf/bpf_cgrp_storage.c +++ b/kernel/bpf/bpf_cgrp_storage.c @@ -118,8 +118,7 @@ static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c index e54cce2b9175..cedc99184dad 100644 --- a/kernel/bpf/bpf_inode_storage.c +++ b/kernel/bpf/bpf_inode_storage.c @@ -110,9 +110,7 @@ static int inode_storage_delete(struct inode *inode, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 9c2b041ae9ca..e0e405060e3c 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -433,7 +433,7 @@ static void bpf_selem_link_map_nolock(struct bpf_local_storage_map *smap, hlist_add_head_rcu(&selem->map_node, &b->list); } -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) { struct bpf_local_storage_map *storage_smap; struct bpf_local_storage *local_storage; @@ -472,6 +472,8 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) if (free_local_storage) bpf_local_storage_free(local_storage, storage_smap, bpf_ma, reuse_now); + + return 0; } void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage, @@ -930,7 +932,7 @@ void bpf_local_storage_map_free(struct bpf_map *map, struct bpf_local_storage_elem, map_node))) { if (busy_counter) this_cpu_inc(*busy_counter); - bpf_selem_unlink(selem, true); + while (bpf_selem_unlink(selem, true)); if (busy_counter) this_cpu_dec(*busy_counter); cond_resched_rcu(); diff --git a/kernel/bpf/bpf_task_storage.c b/kernel/bpf/bpf_task_storage.c index a1dc1bf0848a..ab902364ac23 100644 --- a/kernel/bpf/bpf_task_storage.c +++ b/kernel/bpf/bpf_task_storage.c @@ -167,9 +167,7 @@ static int task_storage_delete(struct task_struct *task, struct bpf_map *map, if (!nobusy) return -EBUSY; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } static long bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key) diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index fac5cf385785..7b3d44667cee 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -40,9 +40,7 @@ static int bpf_sk_storage_del(struct sock *sk, struct bpf_map *map) if (!sdata) return -ENOENT; - bpf_selem_unlink(SELEM(sdata), false); - - return 0; + return bpf_selem_unlink(SELEM(sdata), false); } /* Called by __sk_destruct() & bpf_sk_storage_clone() */ -- 2.47.3