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authorBen Hutchings <bhutchings@solarflare.com>2012-08-20 22:16:51 +0100
committerDavid S. Miller <davem@davemloft.net>2012-08-24 12:46:13 -0400
commit8f4cccbbd92f2ad0ddbbc498ef7cee2a1c3defe9 (patch)
tree71d1c7b84ce009b287c448a12ed76e17b772f054 /net/core/dev.c
parent9f35a7342cff0be72e3c038ea972e07662ca1ce8 (diff)
downloadop-kernel-dev-8f4cccbbd92f2ad0ddbbc498ef7cee2a1c3defe9.zip
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net: Set device operstate at registration time
The operstate of a device is initially IF_OPER_UNKNOWN and is updated asynchronously by linkwatch after each change of carrier state reported by the driver. The default carrier state of a net device is on, and this will never be changed on drivers that do not support carrier detection, thus the operstate remains IF_OPER_UNKNOWN. For devices that do support carrier detection, the driver must set the carrier state to off initially, then poll the hardware state when the device is opened. However, we must not activate linkwatch for a unregistered device, and commit b473001 ('net: Do not fire linkwatch events until the device is registered.') ensured that we don't. But this means that the operstate for many devices that support carrier detection remains IF_OPER_UNKNOWN when it should be IF_OPER_DOWN. The same issue exists with the dormant state. The proper initialisation sequence, avoiding a race with opening of the device, is: rtnl_lock(); rc = register_netdevice(dev); if (rc) goto out_unlock; netif_carrier_off(dev); /* or netif_dormant_on(dev) */ rtnl_unlock(); but it seems silly that this should have to be repeated in so many drivers. Further, the operstate seen immediately after opening the device may still be IF_OPER_UNKNOWN due to the asynchronous nature of linkwatch. Commit 22604c8 ('net: Fix for initial link state in 2.6.28') attempted to fix this by setting the operstate synchronously, but it was reverted as it could lead to deadlock. This initialises the operstate synchronously at registration time only. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
-rw-r--r--net/core/dev.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index bc857fe..2f25d0c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5648,6 +5648,8 @@ int register_netdevice(struct net_device *dev)
set_bit(__LINK_STATE_PRESENT, &dev->state);
+ linkwatch_init_dev(dev);
+
dev_init_scheduler(dev);
dev_hold(dev);
list_netdevice(dev);
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