bpf: Remove migrate_{disable|enable} from bpf_local_storage_free()

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().

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20250108010728.207536-16-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: Hou Tao

kernel/bpf/bpf_local_storage.c

@@ -172,17 +172,14 @@ 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 */