From: Hou Tao <houtao1@xxxxxxxxxx>
bpf_local_storage_free() has three callers:
1) bpf_local_storage_alloc()
Its caller must have disabled migration.
2) bpf_local_storage_destroy()
Its four callers (bpf_{cgrp|inode|task|sk}_storage_free()) have already
invoked migrate_disable() before invoking bpf_local_storage_destroy().
3) bpf_selem_unlink()
Its callers include: cgrp/inode/task/sk storage ->map_delete_elem
callbacks, bpf_{cgrp|inode|task|sk}_storage_delete() helpers and
bpf_local_storage_map_free(). All of these callers have already disabled
migration before invoking bpf_selem_unlink().
Therefore, it is OK to remove migrate_{disable|enable} pair from
bpf_local_storage_free(). Also add a cant_migrate() check in
bpf_local_storage_free() to ensure the guarantee isn't broken.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
kernel/bpf/bpf_local_storage.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 0970766278f7..d67ba116aee8 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -163,6 +163,8 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
if (!local_storage)
return;
+ cant_migrate();
+
if (!bpf_ma) {
__bpf_local_storage_free(local_storage, reuse_now);
return;
@@ -174,17 +176,14 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
return;
}
- if (smap) {
- migrate_disable();
+ if (smap)
bpf_mem_cache_free(&smap->storage_ma, local_storage);
- migrate_enable();
- } else {
+ else
/* smap could be NULL if the selem that triggered
* this 'local_storage' creation had been long gone.
* In this case, directly do call_rcu().
*/
call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu);
- }
}
/* rcu tasks trace callback for bpf_ma == false */
--
2.29.2
