From: Breno Leitao leitao@debian.org
[ Upstream commit d8afe2f8a92d2aac3df645772f6ee61b0b2fc147 ]
This patch removes the msleep(4s) during netpoll_setup() if the carrier appears instantly.
Here are some scenarios where this workaround is counter-productive in modern ages:
Servers which have BMC communicating over NC-SI via the same NIC as gets used for netconsole. BMC will keep the PHY up, hence the carrier appearing instantly.
The link is fibre, SERDES getting sync could happen within 0.1Hz, and the carrier also appears instantly.
Other than that, if a driver is reporting instant carrier and then losing it, this is probably a driver bug.
Reported-by: Michael van der Westhuizen rmikey@meta.com Signed-off-by: Breno Leitao leitao@debian.org Link: https://lore.kernel.org/r/20230125185230.3574681-1-leitao@debian.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/netpoll.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 960948290001e..ee2022b9616bf 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -694,7 +694,7 @@ int netpoll_setup(struct netpoll *np) }
if (!netif_running(ndev)) { - unsigned long atmost, atleast; + unsigned long atmost;
np_info(np, "device %s not up yet, forcing it\n", np->dev_name);
@@ -706,7 +706,6 @@ int netpoll_setup(struct netpoll *np) }
rtnl_unlock(); - atleast = jiffies + HZ/10; atmost = jiffies + carrier_timeout * HZ; while (!netif_carrier_ok(ndev)) { if (time_after(jiffies, atmost)) { @@ -716,15 +715,6 @@ int netpoll_setup(struct netpoll *np) msleep(1); }
- /* If carrier appears to come up instantly, we don't - * trust it and pause so that we don't pump all our - * queued console messages into the bitbucket. - */ - - if (time_before(jiffies, atleast)) { - np_notice(np, "carrier detect appears untrustworthy, waiting 4 seconds\n"); - msleep(4000); - } rtnl_lock(); }