On Tue, Sep 19, 2023 at 09:47:55PM +0200, Philipp Stanner wrote: > The header contains a comment that details why the functions > list_empty_rcu() and list_first_entry_rcu() don't exist. It explains > that they don't exist because standard list_empty() can be used just as > well, but one can not expect sane results from a subsequent, quote, > "list_first_entry_rcu()". > > This function (obviously) does not exist. What the comment's author > actually meant was the standard list-function list_first_entry(). > > Change the function name in that comment from list_first_entry_rcu() to > list_first_entry(). > > Additionally, add the parenthesis to list_first_or_null_rcu to be congruent > with that entire comment's style. > > Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx> > --- > Hi! > I hope this helps. > I wasn't 100.000000% sure if that's correct, but I thought asking is for > free 8-) > > Regards, > P. Thank you for sending this! Please see below. Thanx, Paul > --- > include/linux/rculist.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h > index d29740be4833..4837d8892691 100644 > --- a/include/linux/rculist.h > +++ b/include/linux/rculist.h > @@ -331,9 +331,9 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, > * rcu_dereference() is not needed), which means that list_empty() can be > * used anywhere you would want to use list_empty_rcu(). Just don't > * expect anything useful to happen if you do a subsequent lockless > - * call to list_first_entry_rcu()!!! > + * call to list_first_entry()!!! You are quite correct that the original is incorrect, given that it does not exist, but a better change would be to list_entry_rcu(). The reason being that list_first_entry() does not have READ_ONCE(), allowing the compiler to play all sorts of games (see https://lwn.net/Articles/793253 for some examples). > * > - * See list_first_or_null_rcu for an alternative. > + * See list_first_or_null_rcu() for an alternative. Good catch! Please do feel free to send an update. Thanx, Paul > */ > > /** > -- > 2.41.0 >
