* Re: [ofa-general] [PATCH] IB/IPoIB: Fix change mtu when switching to UD mode [not found] ` <486A1CB1.1020904@voltaire.com> @ 2008-07-01 13:42 ` Eli Cohen 2008-07-01 13:45 ` Eli Cohen 0 siblings, 1 reply; 2+ messages in thread From: Eli Cohen @ 2008-07-01 13:42 UTC (permalink / raw) To: Or Gerlitz; +Cc: netdev, Roland Dreier, general-list On Tue, Jul 01, 2008 at 03:01:53PM +0300, Or Gerlitz wrote: > The calls to dev_set_mtu from the bonding driver are from the device > .set_mtu function and this means that the caller have taken the appropriate > locking needed (set mtu is done on the master which in turn does it on the > slaves). Recently, I worked on some change to bonding and throughout this > work I learned on the need (must) to call the rtnl locking when invoking a > dev_set_x function who further does call_netdevice_notifiers(), see > > "the correct locking context for the notifier calls (which is RTNL and > nothing else)" > > comment from the bonding maintainer in > http://marc.info/?l=linux-netdev&m=121201324611292&w=2 > I see, though I would expect to see a comment stating this requirement both at the documentation of call_netdevice_notifiers() and that of dev_set_mtu() and any other exported functions that requires this kind of locking. Moreover, in this specific case, it appears that it is not required to take the rtlnl lock -- if it would be a must, I would have experienced a dump_stack() due to ASSERT_RTNL(); in bond_alb_handle_active_change(). The fact that I did not hit such an assert does not mean I may avoid taking the rtnl lock but it appears to me that the issue is not well undrestood. ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [ofa-general] [PATCH] IB/IPoIB: Fix change mtu when switching to UD mode 2008-07-01 13:42 ` [ofa-general] [PATCH] IB/IPoIB: Fix change mtu when switching to UD mode Eli Cohen @ 2008-07-01 13:45 ` Eli Cohen 0 siblings, 0 replies; 2+ messages in thread From: Eli Cohen @ 2008-07-01 13:45 UTC (permalink / raw) To: Or Gerlitz; +Cc: netdev, Roland Dreier, general-list On Tue, Jul 01, 2008 at 04:42:29PM +0300, Eli Cohen wrote: > > I see, though I would expect to see a comment stating this requirement > both at the documentation of call_netdevice_notifiers() and that of > dev_set_mtu() and any other exported functions that requires this kind > of locking. > Moreover, in this specific case, it appears that it is not required to > take the rtlnl lock -- if it would be a must, I would have experienced > a dump_stack() due to > > ASSERT_RTNL(); > > in bond_alb_handle_active_change(). Or some other function registered for notifications. > > > The fact that I did not hit such an assert does not mean I may avoid > taking the rtnl lock but it appears to me that the issue is not well > undrestood. > _______________________________________________ > general mailing list > general@lists.openfabrics.org > http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general > > To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general ^ permalink raw reply [flat|nested] 2+ messages in thread
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2008-07-01 13:42 ` [ofa-general] [PATCH] IB/IPoIB: Fix change mtu when switching to UD mode Eli Cohen
2008-07-01 13:45 ` Eli Cohen
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