On Mon, Dec 06, 2021 at 03:12:38PM -0600, Bob Pearson wrote:
> +/**
> + * rxe_pool_add_key() - lookup or add object with key in pool
> + * @pool: the object pool
> + * @key: the key
> + *
> + * Returns: If object matching key is present in pool return
> + * its address and take a reference else allocate a
> + * new object to pool with key and return its address
> + * with one reference.
> + */
> +void *rxe_pool_add_key(struct rxe_pool *pool, void *key)
> +{
> + void *obj;
> +
> + rxe_pool_lock_bh(pool);
> + obj = __rxe_get_key(pool, key);
> + if (obj)
> + goto done;
> +
> + obj = __rxe_alloc(pool, GFP_ATOMIC);
Really try hard to avoid GFP_ATOMIC:
rxe_pool_lock_bh(pool);
obj = __rxe_get_key(pool, key);
rxe_pool_unlock_bh(pool);
if (obj)
return obj;
obj = __rxe_alloc(pool, GFP_KERNEL);
if (!obj)
return NULL;
rxe_pool_lock_bh(pool);
old_obj = __xa_cmpxchg(&pool->xarray.xa, key, NULL, entry, GFP_KERNEL);
if (xa_is_err(old_obj))
kfree(obj)
return NULL;
if (old_obj) {
kfree(obj);
obj = old_obj;
}
kref_get(old_obj)
rxe_pool_unlock_bh(pool);
return obj;
If it is very rare that this function would collide the index then
forget the first lookup and use the cmpxchg
> +void rxe_elem_release(struct kref *kref)
> +{
> + struct rxe_pool_elem *elem =
> + container_of(kref, struct rxe_pool_elem, ref_cnt);
> + struct rxe_pool *pool = elem->pool;
> +
> + if (pool->flags & RXE_POOL_INDEX)
> + __xa_erase(&pool->xarray.xa, elem->index);
> +
> + if (pool->flags & RXE_POOL_KEY)
> + rb_erase(&elem->key_node, &pool->key.tree);
It is a bit jarring to see these as not exclusive ?
Jason
