Previous commits has removed the queue freeze in nbd_add_socket and nbd_set_size during nbd device setup. However, a queue freeze can still occur when nbd_start_device calls blk_mq_update_nr_hw_queues if the socket connection count does not match nbd->tag_set->nr_hw_queues. The nbd_start_device function can be invoked through either the ioctl or netlink paths. The ioctl path only allows reusing an existing inactivate nbd device, there is nothing more we can do to prevent the queue freeze since the old nbd->tag_set->nr_hw_queues may not match the new socket connection count. Similarly, the netlink path can reuse a preferred inactivate nbd device, and again, we cannot do more in this scenario. However, the netlink path can also add a new nbd device using nbd_dev_add. In this case, we can obtain the new number of socket connections, and by adding a new argument representing the expected nr_hw_queues in nbd_dev_add, we can ensure the queue freeze is avoided for this situation. Signed-off-by: Yang Erkun --- drivers/block/nbd.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 4b9f0349877e..2bb98e41b99b 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1937,7 +1937,8 @@ static const struct blk_mq_ops nbd_mq_ops = { .timeout = nbd_xmit_timeout, }; -static struct nbd_device *nbd_dev_add(int index, unsigned int refs) +static struct nbd_device *nbd_dev_add(int index, unsigned int refs, + int nr_hw_queues) { struct queue_limits lim = { .max_hw_sectors = 65536, @@ -1954,7 +1955,7 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs) goto out; nbd->tag_set.ops = &nbd_mq_ops; - nbd->tag_set.nr_hw_queues = 1; + nbd->tag_set.nr_hw_queues = nr_hw_queues; nbd->tag_set.queue_depth = 128; nbd->tag_set.numa_node = NUMA_NO_NODE; nbd->tag_set.cmd_size = sizeof(struct nbd_cmd); @@ -2208,7 +2209,11 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) mutex_unlock(&nbd_index_mutex); if (!nbd) { - nbd = nbd_dev_add(index, 2); + ret = nbd_genl_foreach_sock(info, NULL, NULL); + if (ret < 0) + return ret; + + nbd = nbd_dev_add(index, 2, ret > 0 ? ret : 1); if (IS_ERR(nbd)) { pr_err("failed to add new device\n"); return PTR_ERR(nbd); @@ -2729,7 +2734,7 @@ static int __init nbd_init(void) nbd_dbg_init(); for (i = 0; i < nbds_max; i++) - nbd_dev_add(i, 1); + nbd_dev_add(i, 1, 1); return 0; } -- 2.52.0