lkml.org 
[lkml]   [2018]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/4] rculist: add list_for_each_entry_from_rcu()
On Mon, 30 Apr 2018 06:43:08 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> 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

-- Steve

\
 
 \ /
  Last update: 2018-04-30 17:15    [W:0.068 / U:1.564 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site