Re: [PATCH] RDS: Simplify code

On Sun, Sep 04, 2016 at 05:57:20PM +0200, Christophe JAILLET wrote:

Le 04/09/2016 à 14:20, Leon Romanovsky a écrit :

quoted

On Sat, Sep 03, 2016 at 07:33:29AM +0200, Christophe JAILLET wrote:

quoted

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         }

CJ