list_for_each_safe is able to handle an empty list. The only effect of avoiding the loop is not initializing the index variable. Drop list_empty tests in cases where these variables are not used.
The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) <smpl> @@ expression x,e; iterator name list_for_each_safe; statement S; identifier i,j; @@ -if (!(list_empty(x))) { list_for_each_safe(i,j,x) S - } ... when != i when != j ( i = e; | ? j = e; ) </smpl> Signed-off-by: Julia Lawall <julia.law...@inria.fr> --- drivers/net/ethernet/sfc/ptp.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c index 393b7cb..bea4725 100644 --- a/drivers/net/ethernet/sfc/ptp.c +++ b/drivers/net/ethernet/sfc/ptp.c @@ -1154,17 +1154,15 @@ static void efx_ptp_drop_time_expired_events(struct efx_nic *efx) /* Drop time-expired events */ spin_lock_bh(&ptp->evt_lock); - if (!list_empty(&ptp->evt_list)) { - list_for_each_safe(cursor, next, &ptp->evt_list) { - struct efx_ptp_event_rx *evt; - - evt = list_entry(cursor, struct efx_ptp_event_rx, - link); - if (time_after(jiffies, evt->expiry)) { - list_move(&evt->link, &ptp->evt_free_list); - netif_warn(efx, hw, efx->net_dev, - "PTP rx event dropped\n"); - } + list_for_each_safe(cursor, next, &ptp->evt_list) { + struct efx_ptp_event_rx *evt; + + evt = list_entry(cursor, struct efx_ptp_event_rx, + link); + if (time_after(jiffies, evt->expiry)) { + list_move(&evt->link, &ptp->evt_free_list); + netif_warn(efx, hw, efx->net_dev, + "PTP rx event dropped\n"); } } spin_unlock_bh(&ptp->evt_lock);
