On Mon, Apr 30, 2018 at 11:14:54AM -0400, Steven Rostedt wrote: > On Mon, 30 Apr 2018 06:43:08 -0700 > "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > > > On Sun, Apr 29, 2018 at 10:20:33PM -0700, Josh Triplett wrote: > > > On Mon, Apr 30, 2018 at 02:31:30PM +1000, NeilBrown wrote: > > > > list_for_each_entry_from_rcu() is an RCU version of > > > > list_for_each_entry_from(). It walks a linked list under rcu > > > > protection, from a given start point. > > > > > > > > It is similar to list_for_each_entry_continue_rcu() but starts *at* > > > > the given position rather than *after* it. > > > > > > > > Naturally, the start point must be known to be in the list. > > > > > > I'd suggest giving an explicit advisory comment to clarify and suggest > > > correct usage: > > > > > > "This would typically require either that you obtained the node from a > > > previous walk of the list in the same RCU read-side critical section, or > > > that you held some sort of non-RCU reference (such as a reference count) > > > to keep the node alive *and* in the list." > > > > > > (Feel free to wordsmith the exact wording, but something like that seems > > > like it would help people understand how to use this correctly, and make > > > it less likely that they'd use it incorrectly.) > > > > What Josh said! Could you also contrast this with the existing > > list_for_each_entry_continue_rcu() macro in the header comment as well > > as in the commit log? > > Should Documentation/RCU/whatisRCU.txt be updated? > > Specifically section: 7. FULL LIST OF RCU APIs Very much so, thank you for catching this! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
