Re: [PATCHv2 2/2] RDMA/rxe: Use different xa locks on different path

[Jason Gunthorpe <jgg@ziepe.ca>]

On Sat, Apr 16, 2022 at 10:43:43PM -0400, yanjun.zhu@linux.dev wrote:
> From: Zhu Yanjun <yanjun.zhu@linux.dev>
> 
> The function __rxe_add_to_pool is called on different path, and the
> requirement of the locks is different. The function rxe_create_ah
> requires xa_lock_irqsave/irqrestore while others only require xa_lock_irq.
> 
> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
> V1->V2: Use pool type instead of gfp_t;
>  drivers/infiniband/sw/rxe/rxe_pool.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
> index f1f06dc7e64f..5b097d6666eb 100644
> +++ b/drivers/infiniband/sw/rxe/rxe_pool.c
> @@ -157,7 +157,6 @@ void *rxe_alloc(struct rxe_pool *pool)
>  int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_elem *elem)
>  {
>  	int err;
> -	unsigned long flags;
>  
>  	if (WARN_ON(pool->flags & RXE_POOL_ALLOC))
>  		return -EINVAL;
> @@ -169,10 +168,19 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_elem *elem)
>  	elem->obj = (u8 *)elem - pool->elem_offset;
>  	kref_init(&elem->ref_cnt);
>  
> -	xa_lock_irqsave(&pool->xa, flags);
> -	err = __xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit,
> -				&pool->next, GFP_ATOMIC);
> -	xa_unlock_irqrestore(&pool->xa, flags);
> +	if (pool->type == RXE_TYPE_AH) {
> +		unsigned long flags;
> +
> +		xa_lock_irqsave(&pool->xa, flags);
> +		err = __xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit,
> +					&pool->next, GFP_ATOMIC);
> +		xa_unlock_irqrestore(&pool->xa, flags);

This is still not right - you have to test RDMA_CREATE_AH_SLEEPABLE
for the AH path as well.

Jason