linux-kernel - [PATCH 2.6.27-rc8 3/6] e1000e: remove phy read from inside spinlock

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Message-ID: <20081002233330.12556.79763.stgit@jbrandeb-bw.jf.intel.com>
Date:	Thu, 02 Oct 2008 16:33:30 -0700
From:	Jesse Brandeburg <jesse.brandeburg@...el.com>
To:	torvalds@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	tglx@...utronix.de, arjan@...ux.intel.com, airlied@...il.com,
	davem@...emloft.net, jeff@...zik.org,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 2.6.27-rc8 3/6] e1000e: remove phy read from inside spinlock

thanks to tglx, we're finding some interesting reentrancy issues.
this patch removes the phy read from inside a spinlock, paving
the way for removing the spinlock completely.  The phy read was
only feeding a statistic that wasn't used.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
CC: Thomas Gleixner <tglx@...utronix.de>
---

 drivers/net/e1000e/ethtool.c |    6 +++++-
 drivers/net/e1000e/netdev.c  |   13 -------------
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/drivers/net/e1000e/ethtool.c b/drivers/net/e1000e/ethtool.c
index 5ed8e13..33a3ff1 100644
--- a/drivers/net/e1000e/ethtool.c
+++ b/drivers/net/e1000e/ethtool.c
@@ -432,6 +432,10 @@ static void e1000_get_regs(struct net_device *netdev,
 	regs_buff[11] = er32(TIDV);
 
 	regs_buff[12] = adapter->hw.phy.type;  /* PHY type (IGP=1, M88=0) */
+
+	/* ethtool doesn't use anything past this point, so all this
+	 * code is likely legacy junk for apps that may or may not
+	 * exist */
 	if (hw->phy.type == e1000_phy_m88) {
 		e1e_rphy(hw, M88E1000_PHY_SPEC_STATUS, &phy_data);
 		regs_buff[13] = (u32)phy_data; /* cable length */
@@ -447,7 +451,7 @@ static void e1000_get_regs(struct net_device *netdev,
 		regs_buff[22] = adapter->phy_stats.receive_errors;
 		regs_buff[23] = regs_buff[13]; /* mdix mode */
 	}
-	regs_buff[21] = adapter->phy_stats.idle_errors;  /* phy idle errors */
+	regs_buff[21] = 0; /* was idle_errors */
 	e1e_rphy(hw, PHY_1000T_STATUS, &phy_data);
 	regs_buff[24] = (u32)phy_data;  /* phy local receiver status */
 	regs_buff[25] = regs_buff[24];  /* phy remote receiver status */
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 803545b..835b692 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -2954,9 +2954,6 @@ void e1000e_update_stats(struct e1000_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	struct pci_dev *pdev = adapter->pdev;
 	unsigned long irq_flags;
-	u16 phy_tmp;
-
-#define PHY_IDLE_ERROR_COUNT_MASK 0x00FF
 
 	/*
 	 * Prevent stats update while adapter is being reset, or if the pci
@@ -3045,15 +3042,6 @@ void e1000e_update_stats(struct e1000_adapter *adapter)
 
 	/* Tx Dropped needs to be maintained elsewhere */
 
-	/* Phy Stats */
-	if (hw->phy.media_type == e1000_media_type_copper) {
-		if ((adapter->link_speed == SPEED_1000) &&
-		   (!e1e_rphy(hw, PHY_1000T_STATUS, &phy_tmp))) {
-			phy_tmp &= PHY_IDLE_ERROR_COUNT_MASK;
-			adapter->phy_stats.idle_errors += phy_tmp;
-		}
-	}
-
 	/* Management Stats */
 	adapter->stats.mgptc += er32(MGTPTC);
 	adapter->stats.mgprc += er32(MGTPRC);
@@ -3073,7 +3061,6 @@ static void e1000_phy_read_status(struct e1000_adapter *adapter)
 	int ret_val;
 	unsigned long irq_flags;
 
-
 	spin_lock_irqsave(&adapter->stats_lock, irq_flags);
 
 	if ((er32(STATUS) & E1000_STATUS_LU) &&

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