Re: [PATCH] RDS: Simplify code

[santosh.shilimkar@xxxxxxxxxx]

On 9/4/16 11:23 AM, Leon Romanovsky wrote:
> On Sun, Sep 04, 2016 at 05:57:20PM +0200, Christophe JAILLET wrote:
> > Le 04/09/2016 à 14:20, Leon Romanovsky a écrit :
> > > On Sat, Sep 03, 2016 at 07:33:29AM +0200, Christophe JAILLET wrote:
> > > > Calling 'list_splice' followed by 'INIT_LIST_HEAD' is equivalent to
> > > > 'list_splice_init'.
> > > It is not 100% accurate
> > >
> > > list_splice(y, z)
> > > INIT_LIST_HEAD(y)
> > >
> > > ==>
> > >
> > > if (!list_empty(y))
> > >      __list_splice(y, z, z>next);
> > > INIT_LIST_HEAD(y)
> > >
> > > and not
> > >
> > > if (!list_empty(y)) {
> > >      __list_splice(y, z, z>next);
> > >      INIT_LIST_HEAD(y)
> > > }
> > >
> > > as list_splice_init will do.
> > You are right but if you dig further you will see that calling
> > INIT_LIST_HEAD on an empty list is a no-op (AFAIK).
> > And if this list was not already correctly initialized, then you would have
> > some other troubles.
>
> Thank you for the suggestion,
> It looks like the code after that can be skipped in case of loop_conns
> list is empty, the tmp_list will be empty too.
>
> 174         list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) {
> 175                 WARN_ON(lc->conn->c_passive);
> 176                 rds_conn_destroy(lc->conn);
> 177         }

Thanks for trying. As already pointed, your change doesn't simplify
much rather change the behavior. The loop cursor already takes care
of list empty case. I don't see any reason to change that code.

Regards,
Santosh