Paul E. McKenney
2013-Oct-12 17:13 UTC
[Bridge] [PATCH v3 tip/core/rcu 0/14] Sparse-related updates for 3.13
On Fri, Oct 11, 2013 at 11:53:27PM -0700, Josh Triplett wrote:> On Fri, Oct 11, 2013 at 04:16:59PM -0700, Paul E. McKenney wrote: > > Changes from v2: > > > > o Switch from rcu_assign_pointer() to ACCESS_ONCE() given that > > the pointers are all --rcu and already visible to readers, > > as suggested by Eric Dumazet and Josh Triplett. > > Hang on a moment. Do *none* of these cases need write memory barriers?Sigh. Some afternoons it doesn't pay to touch the keyboard. Thank you for catching this. I will fix, but at this point, I am thinking in terms of 3.14 rather than 3.13 for this series. Thanx, Paul
Hannes Frederic Sowa
2013-Oct-12 17:39 UTC
[Bridge] [PATCH v3 tip/core/rcu 0/14] Sparse-related updates for 3.13
On Sat, Oct 12, 2013 at 10:13:45AM -0700, Paul E. McKenney wrote:> On Fri, Oct 11, 2013 at 11:53:27PM -0700, Josh Triplett wrote: > > On Fri, Oct 11, 2013 at 04:16:59PM -0700, Paul E. McKenney wrote: > > > Changes from v2: > > > > > > o Switch from rcu_assign_pointer() to ACCESS_ONCE() given that > > > the pointers are all --rcu and already visible to readers, > > > as suggested by Eric Dumazet and Josh Triplett. > > > > Hang on a moment. Do *none* of these cases need write memory barriers? > > Sigh. Some afternoons it doesn't pay to touch the keyboard. > > Thank you for catching this. I will fix, but at this point, I am thinking > in terms of 3.14 rather than 3.13 for this series.Some of them looked safe. You could also replace --rcu with __rcu in the comments while at it. Thanks, Hannes
Hannes Frederic Sowa
2013-Oct-12 17:43 UTC
Re: [PATCH v3 tip/core/rcu 0/14] Sparse-related updates for 3.13
On Sat, Oct 12, 2013 at 07:39:30PM +0200, Hannes Frederic Sowa wrote:> On Sat, Oct 12, 2013 at 10:13:45AM -0700, Paul E. McKenney wrote: > > On Fri, Oct 11, 2013 at 11:53:27PM -0700, Josh Triplett wrote: > > > On Fri, Oct 11, 2013 at 04:16:59PM -0700, Paul E. McKenney wrote: > > > > Changes from v2: > > > > > > > > o Switch from rcu_assign_pointer() to ACCESS_ONCE() given that > > > > the pointers are all --rcu and already visible to readers, > > > > as suggested by Eric Dumazet and Josh Triplett. > > > > > > Hang on a moment. Do *none* of these cases need write memory barriers? > > > > Sigh. Some afternoons it doesn''t pay to touch the keyboard. > > > > Thank you for catching this. I will fix, but at this point, I am thinking > > in terms of 3.14 rather than 3.13 for this series. > > Some of them looked safe. You could also replace --rcu with __rcu in the > comments while at it.Most of them deal with management, maybe a rtnl_assign_pointer with lockdep check for rtnl lock could help to not clean up the wrong bits. I don''t know if rtnl_assign_pointer is that a could name as it does not really explain why the barrier is not needed there. :/ Greetings, Hannes
Paul E. McKenney
2013-Oct-13 11:15 UTC
Re: [PATCH v3 tip/core/rcu 0/14] Sparse-related updates for 3.13
On Sat, Oct 12, 2013 at 07:39:30PM +0200, Hannes Frederic Sowa wrote:> On Sat, Oct 12, 2013 at 10:13:45AM -0700, Paul E. McKenney wrote: > > On Fri, Oct 11, 2013 at 11:53:27PM -0700, Josh Triplett wrote: > > > On Fri, Oct 11, 2013 at 04:16:59PM -0700, Paul E. McKenney wrote: > > > > Changes from v2: > > > > > > > > o Switch from rcu_assign_pointer() to ACCESS_ONCE() given that > > > > the pointers are all --rcu and already visible to readers, > > > > as suggested by Eric Dumazet and Josh Triplett. > > > > > > Hang on a moment. Do *none* of these cases need write memory barriers? > > > > Sigh. Some afternoons it doesn''t pay to touch the keyboard. > > > > Thank you for catching this. I will fix, but at this point, I am thinking > > in terms of 3.14 rather than 3.13 for this series. > > Some of them looked safe. You could also replace --rcu with __rcu in the > comments while at it.Sigh! Will do, thank you! Thanx, Paul