From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: [PATCH] Add NETIF_F_LLTX to e1000 driver Date: Tue, 31 Aug 2004 14:46:03 +0200 Sender: netdev-bounce@oss.sgi.com Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: To: netdev@oss.sgi.com, davem@redhat.com, kuznet@ms2.inr.ac.ru, cramerj@intel.com, john.ronciak@intel.com, ganesh.venkatesan@intel.com, jgarzik@pobox.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org This patch adds NETIF_F_LLTX to the e1000 driver. With this the driver can take one lock less in the TX path. It will do a try lock on the tx_lock now and bail out when the lock is already locked. I extended the use of tx_lock a bit to protect some data structures that were previously only protected by the xmit_lock. I also added taking of tx_lock to the set_multicast_list to prevent any potential races here. It requires the lltx patch I sent before to netdev applied first. -Andi diff -u linux-2.6.8-work/drivers/net/e1000/e1000_main.c-o linux-2.6.8-work/drivers/net/e1000/e1000_main.c --- linux-2.6.8-work/drivers/net/e1000/e1000_main.c-o 2004-07-27 14:44:07.000000000 +0200 +++ linux-2.6.8-work/drivers/net/e1000/e1000_main.c 2004-08-31 14:43:43.000000000 +0200 @@ -486,6 +486,9 @@ #endif #endif + /* hard_start_xmit is safe against parallel locking */ + netdev->features |= NETIF_F_LLTX; + if(pci_using_dac) netdev->features |= NETIF_F_HIGHDMA; @@ -1259,9 +1262,12 @@ uint32_t rctl; uint32_t hash_value; int i; + unsigned long flags; /* Check for Promiscuous and All Multicast modes */ + spin_lock_irqsave(&adapter->tx_lock, flags); + rctl = E1000_READ_REG(hw, RCTL); if(netdev->flags & IFF_PROMISC) { @@ -1310,6 +1316,8 @@ if(hw->mac_type == e1000_82542_rev2_0) e1000_leave_82542_rst(adapter); + + spin_unlock_irqrestore(&adapter->tx_lock, flags); } /* need to wait a few seconds after link up to get diagnostic information from the phy */ @@ -1785,7 +1793,13 @@ if(adapter->pcix_82544) count += nr_frags; - spin_lock_irqsave(&adapter->tx_lock, flags); + local_irq_save(flags); + if (!spin_trylock(&adapter->tx_lock)) { + /* Collision - tell upper layer to requeue */ + local_irq_restore(flags); + return -1; + } + /* need: count + 2 desc gap to keep tail from touching * head, otherwise try next time */ if(E1000_DESC_UNUSED(&adapter->tx_ring) < count + 2 ) { @@ -1793,11 +1807,11 @@ spin_unlock_irqrestore(&adapter->tx_lock, flags); return 1; } - spin_unlock_irqrestore(&adapter->tx_lock, flags); if(adapter->hw.mac_type == e1000_82547) { if(e1000_82547_fifo_workaround(adapter, skb)) { netif_stop_queue(netdev); + spin_unlock_irqrestore(&adapter->tx_lock, flags); mod_timer(&adapter->tx_fifo_stall_timer, jiffies); return 1; } @@ -1821,6 +1835,7 @@ netdev->trans_start = jiffies; + spin_unlock_irqrestore(&adapter->tx_lock, flags); return 0; }