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| author | Mitch A Williams <mitch.a.williams@intel.com> | 2012-06-30 02:23:19 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-07-01 02:40:45 +0200 |
| commit | 0e90b49ca4b891f085b57559a3071a4feefb496c (patch) | |
| tree | f34c038e177f5ab0779870b6d2a40e0b155bc515 | |
| parent | Merge branch 'master' of git://1984.lsi.us.es/nf (diff) | |
| download | linux-0e90b49ca4b891f085b57559a3071a4feefb496c.tar.xz linux-0e90b49ca4b891f085b57559a3071a4feefb496c.zip | |
igbvf: fix divide by zero
Using ethtool -C ethX rx-usecs 0 crashes with a divide by zero.
Refactor this function to fix this issue and make it more clear
what the intent of each conditional is. Add comment regarding
using a setting of zero.
CC: stable <stable@vger.kernel.org> [3.3+]
CC: David Ahern <daahern@cisco.com>
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/intel/igbvf/ethtool.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/drivers/net/ethernet/intel/igbvf/ethtool.c b/drivers/net/ethernet/intel/igbvf/ethtool.c index 8ce67064b9c5..90eef07943f4 100644 --- a/drivers/net/ethernet/intel/igbvf/ethtool.c +++ b/drivers/net/ethernet/intel/igbvf/ethtool.c @@ -357,21 +357,28 @@ static int igbvf_set_coalesce(struct net_device *netdev, struct igbvf_adapter *adapter = netdev_priv(netdev); struct e1000_hw *hw = &adapter->hw; - if ((ec->rx_coalesce_usecs > IGBVF_MAX_ITR_USECS) || - ((ec->rx_coalesce_usecs > 3) && - (ec->rx_coalesce_usecs < IGBVF_MIN_ITR_USECS)) || - (ec->rx_coalesce_usecs == 2)) - return -EINVAL; - - /* convert to rate of irq's per second */ - if (ec->rx_coalesce_usecs && ec->rx_coalesce_usecs <= 3) { + if ((ec->rx_coalesce_usecs >= IGBVF_MIN_ITR_USECS) && + (ec->rx_coalesce_usecs <= IGBVF_MAX_ITR_USECS)) { + adapter->current_itr = ec->rx_coalesce_usecs << 2; + adapter->requested_itr = 1000000000 / + (adapter->current_itr * 256); + } else if ((ec->rx_coalesce_usecs == 3) || + (ec->rx_coalesce_usecs == 2)) { adapter->current_itr = IGBVF_START_ITR; adapter->requested_itr = ec->rx_coalesce_usecs; - } else { - adapter->current_itr = ec->rx_coalesce_usecs << 2; + } else if (ec->rx_coalesce_usecs == 0) { + /* + * The user's desire is to turn off interrupt throttling + * altogether, but due to HW limitations, we can't do that. + * Instead we set a very small value in EITR, which would + * allow ~967k interrupts per second, but allow the adapter's + * internal clocking to still function properly. + */ + adapter->current_itr = 4; adapter->requested_itr = 1000000000 / (adapter->current_itr * 256); - } + } else + return -EINVAL; writel(adapter->current_itr, hw->hw_addr + adapter->rx_ring->itr_register); |