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From: Shlomo Pongartz <shlomop@mellanox•com>
To: <netdev@vger•kernel.org>
Subject: ndo_get_stats and rtnl_netlink
Date: Sun, 9 Sep 2012 18:23:16 +0300	[thread overview]
Message-ID: <504CB464.6010207@mellanox.com> (raw)

Hi,

Just realized that dev_get_stats which calls into a netdevice 
ndo_get_stats64/ndo_get_stats can be
called with or without RTNL lock protection. If called from 
rtnl_fill_ifinfo e.g as of invocation of
"ip link show <interface>, there IS locking, however if called from 
dev_seq_printf_stats e.g as of
invocation of reading the /sys/class/net/<interface>/statistics/ 
entries, etc more cases -- no locking.

This turned to be problematic when implementing the ethtool 
"set_channels" directive which
changes the number of **rings**, since we stepped on a bug where the 
rings data structure was
changed by the ethtool flow in the same time a statistics call was done 
into the driver, etc.

What would be the way to continue here, per driver lock sounds non 
generic...

Regards
Shlomo Pongratz

             reply	other threads:[~2012-09-09 15:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-09 15:23 Shlomo Pongartz [this message]
2012-09-10  9:09 ` ndo_get_stats and rtnl_netlink Eric Dumazet
2012-09-10 19:10   ` Or Gerlitz
2012-09-10 19:15     ` Eric Dumazet

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