af_packet: refactoring code for prb_calc_retire_blk_tmo

If __ethtool_get_link_ksettings() is failed and with
non-zero value, prb_calc_retire_blk_tmo() should return
DEFAULT_PRB_RETIRE_TOV firstly.

This patch is to refactory code and make it more readable.

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 118cd66..3bec515 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -520,7 +520,7 @@ static int prb_calc_retire_blk_tmo(struct packet_sock *po,
                                int blk_size_in_bytes)
 {
        struct net_device *dev;
-       unsigned int mbits = 0, msec = 0, div = 0, tmo = 0;
+       unsigned int mbits, div;
        struct ethtool_link_ksettings ecmd;
        int err;
 
@@ -532,31 +532,25 @@ static int prb_calc_retire_blk_tmo(struct packet_sock *po,
        }
        err = __ethtool_get_link_ksettings(dev, &ecmd);
        rtnl_unlock();
-       if (!err) {
-               /*
-                * If the link speed is so slow you don't really
-                * need to worry about perf anyways
-                */
-               if (ecmd.base.speed < SPEED_1000 ||
-                   ecmd.base.speed == SPEED_UNKNOWN) {
-                       return DEFAULT_PRB_RETIRE_TOV;
-               } else {
-                       msec = 1;
-                       div = ecmd.base.speed / 1000;
-               }
-       } else
+       if (err)
                return DEFAULT_PRB_RETIRE_TOV;
 
+       /* If the link speed is so slow you don't really
+        * need to worry about perf anyways
+        */
+       if (ecmd.base.speed < SPEED_1000 ||
+           ecmd.base.speed == SPEED_UNKNOWN)
+               return DEFAULT_PRB_RETIRE_TOV;
+
+       div = ecmd.base.speed / 1000;
        mbits = (blk_size_in_bytes * 8) / (1024 * 1024);
 
        if (div)
                mbits /= div;
 
-       tmo = mbits * msec;
-
        if (div)
-               return tmo+1;
-       return tmo;
+               return mbits + 1;
+       return mbits;
 }
 
 static void prb_init_ft_ops(struct tpacket_kbdq_core *p1,