Re: [PATCH V2,net-next, 3/3] hv_netvsc: Name NICs based on vmbus offer sequence and use async probe
From: Roman Kagan <hidden>
Date: 2019-12-31 11:35:40
Also in:
linux-hyperv, lkml
On Mon, Dec 30, 2019 at 12:13:34PM -0800, Haiyang Zhang wrote:
quoted hunk ↗ jump to hunk
The dev_num field in vmbus channel structure is assigned to the first available number when the channel is offered. So netvsc driver uses it for NIC naming based on channel offer sequence. Now re-enable the async probing mode for faster probing. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- drivers/net/hyperv/netvsc_drv.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index f3f9eb8..39c412f 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c@@ -2267,10 +2267,14 @@ static int netvsc_probe(struct hv_device *dev, struct net_device_context *net_device_ctx; struct netvsc_device_info *device_info = NULL; struct netvsc_device *nvdev; + char name[IFNAMSIZ]; int ret = -ENOMEM; - net = alloc_etherdev_mq(sizeof(struct net_device_context), - VRSS_CHANNEL_MAX); + snprintf(name, IFNAMSIZ, "eth%d", dev->channel->dev_num);
How is this supposed to work when there are other ethernet device types on the system, which may claim the same device names?
quoted hunk ↗ jump to hunk
+ net = alloc_netdev_mqs(sizeof(struct net_device_context), name, + NET_NAME_ENUM, ether_setup, + VRSS_CHANNEL_MAX, VRSS_CHANNEL_MAX); + if (!net) goto no_net;@@ -2355,6 +2359,14 @@ static int netvsc_probe(struct hv_device *dev, net->max_mtu = ETH_DATA_LEN; ret = register_netdevice(net); + + if (ret == -EEXIST) { + pr_info("NIC name %s exists, request another name.\n", + net->name); + strlcpy(net->name, "eth%d", IFNAMSIZ); + ret = register_netdevice(net); + }
IOW you want the device naming to be predictable, but don't guarantee this? I think the problem this patchset is trying to solve is much better solved with a udev rule, similar to how it's done for PCI net devices. And IMO the primary channel number, being a device's "hardware" property, is more suited to be used in the device name, than this completely ephemeral device number. Thanks, Roman.
quoted hunk ↗ jump to hunk
+ if (ret != 0) { pr_err("Unable to register netdev.\n"); goto register_failed;@@ -2496,7 +2508,7 @@ static int netvsc_resume(struct hv_device *dev) .suspend = netvsc_suspend, .resume = netvsc_resume, .driver = { - .probe_type = PROBE_FORCE_SYNCHRONOUS, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, };-- 1.8.3.1