Le 04/09/2016 à 20:23, Leon Romanovsky a écrit :
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 }
Yes, but this would require some more code and test. This function
doesn't seem to be in a hot path, so I'm not sure that the added
complexity would worth it.
It would require a new 'list_empty()' test and some code rearrangement.
I suppose that testing for emptiness at the beginning or going through a
list_for_each_entry_safe on a empty list (which will exit immediately
and do nothing) is more or less the same in term of speed. So keep the
code simple and readable.
CJ
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