> -----Original Message-----
> From: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
> Sent: Monday, October 9, 2023 9:18 AM
> To: Bernard Metzler <BMT@xxxxxxxxxxxxxx>; jgg@xxxxxxxx; leon@xxxxxxxxxx
> Cc: linux-rdma@xxxxxxxxxxxxxxx
> Subject: [EXTERNAL] [PATCH 14/19] RDMA/siw: Simplify siw_mem_id2obj
>
> We can set mm then return it.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxx>
> ---
> drivers/infiniband/sw/siw/siw_mem.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/infiniband/sw/siw/siw_mem.c
> b/drivers/infiniband/sw/siw/siw_mem.c
> index ac4502fb0a96..2d62f947d330 100644
> --- a/drivers/infiniband/sw/siw/siw_mem.c
> +++ b/drivers/infiniband/sw/siw/siw_mem.c
> @@ -53,13 +53,11 @@ struct siw_mem *siw_mem_id2obj(struct siw_device *sdev,
> int stag_index)
>
> rcu_read_lock();
> mem = xa_load(&sdev->mem_xa, stag_index);
> - if (likely(mem && kref_get_unless_zero(&mem->ref))) {
> - rcu_read_unlock();
> - return mem;
> - }
> + if (likely(mem && !kref_get_unless_zero(&mem->ref)))
> + mem = NULL;
> rcu_read_unlock();
>
> - return NULL;
> + return mem;
> }
>
> static void siw_free_plist(struct siw_page_chunk *chunk, int num_pages,
> --
> 2.35.3
No let's keep it as is. It openly codes the likely case first.
Your code makes the unlikely thing likely.
