function.
From the submitter:
This patch fixes an issue I encountered using an NFS root with an
ar71xx-based MikroTik RouterBoard 450G on -current where the kernel fails
to contact a DHCP/BOOTP server via if_arge when it otherwise should be able
to. This may be the same issue that Monthadar Al Jaberi reported against
an RSPRO on 6 March, as the signature is the same:
%%%
DHCP/BOOTP timeout for server 255.255.255.255
DHCP/BOOTP timeout for server 255.255.255.255
DHCP/BOOTP timeout for server 255.255.255.255
.
.
.
DHCP/BOOTP timeout for server 255.255.255.255
DHCP/BOOTP timeout for server 255.255.255.255
arge0: initialization failed: no memory for rx buffers
DHCP/BOOTP timeout for server 255.255.255.255
arge0: initialization failed: no memory for rx buffers
%%%
The primary issue that I found is that the DHCP/BOOTP message that
bootpc_call() is sending never makes it onto the wire, which I believe is
due to the following:
- Last December, a change was made to the ifioctl that bootpc_call() uses
to adjust the netmask around the sosend().
- The new ioctl (SIOCAIFADDR) performs an if_init when invoked, whereas the
old one (SIOCSIFNETMASK) did not.
- if_arge maintains its own sense of link state in sc->arge_link_status.
- On a single-phy interface, sc->arge_link_status is initialized to 0 in
arge_init_locked().
- sc->arge_link_status remains 0 until a phy state change notification
causes arge_link_task to run, notice the link is up, and set it to 1.
- The inits caused by the ifioctls in bootpc_call are reinitializing the
interface, but not the phy, so sc->arge_link_status goes to 0 and remains
there.
- arge_start_locked() always sees sc->arge_link_status == 0 and returns
without queuing anything.
The attached patch changes arge_init_locked() such that in the single-phy
case, instead of initializing sc->arge_link_status to 0, it runs
arge_link_task() to set it according to the current phy state. This change
has allowed my setup to mount an NFS root successfully.
Submitted by: Patrick Kelsey <kelsey@ieee.org>
Reviewed by: juli
8a5350984f