Commit 394e6869 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

mm/percpu.c: don't acquire pcpu_lock for pcpu_chunk_addr_search() 



There is no need to acquire pcpu_lock for pcpu_chunk_addr_search():
1) both pcpu_first_chunk & pcpu_reserved_chunk must have been
   initialized before the invocation of free_percpu().
2) The dynamically-created chunk must be valid before the per-cpu
   pointers allocated from it are freed.

So acquire pcpu_lock() after the invocation of pcpu_chunk_addr_search().

Acked-by: default avatarDennis Zhou <dennis@kernel.org>
Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231020133202.4043247-2-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent da1055b6

mm/percpu.c

+1 −3
Original line number Diff line number Diff line
@@ -2267,12 +2267,10 @@ void free_percpu(void __percpu *ptr) 
	kmemleak_free_percpu(ptr);



	addr = __pcpu_ptr_to_addr(ptr);



	spin_lock_irqsave(&pcpu_lock, flags);



	chunk = pcpu_chunk_addr_search(addr);

	off = addr - chunk->base_addr;



	spin_lock_irqsave(&pcpu_lock, flags);

	size = pcpu_free_area(chunk, off);



	pcpu_memcg_free_hook(chunk, off, size);