[bug report] RDMA/rxe: Remove RXE_POOL_ATOMIC

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Bob Pearson,

The patch 4276fd0dddc9: "RDMA/rxe: Remove RXE_POOL_ATOMIC" from Jan
25, 2021, leads to the following
Smatch static checker warning:

	drivers/infiniband/sw/rxe/rxe_pool.c:362 rxe_alloc()
	warn: sleeping in atomic context

drivers/infiniband/sw/rxe/rxe_pool.c
    353 void *rxe_alloc(struct rxe_pool *pool)
    354 {
    355 	struct rxe_type_info *info = &rxe_type_info[pool->type];
    356 	struct rxe_pool_entry *elem;
    357 	u8 *obj;
    358 
    359 	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
    360 		goto out_cnt;
    361 
--> 362 	obj = kzalloc(info->size, GFP_KERNEL);
                                          ^^^^^^^^^^
It's possible the patch just exposed a bug instead of introducing it,
but rxe_mcast_add_grp_elem() calls rxe_alloc() with spin_locks held so
we can't sleep.

    363 	if (!obj)
    364 		goto out_cnt;
    365 
    366 	elem = (struct rxe_pool_entry *)(obj + info->elem_offset);
    367 
    368 	elem->pool = pool;
    369 	kref_init(&elem->ref_cnt);
    370 
    371 	return obj;
    372 
    373 out_cnt:
    374 	atomic_dec(&pool->num_elem);
    375 	return NULL;
    376 }

regards,
dan carpenter