From 717d438d1fde94decef874b9808379d1f4523453 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 2 Oct 2008 16:33:40 -0700 Subject: e1000e: debug contention on NVM SWFLAG This patch adds a mutex to the e1000e driver that would help catch any collisions of two e1000e threads accessing hardware at the same time. description and patch updated by Jesse Signed-off-by: Thomas Gleixner Signed-off-by: Jesse Brandeburg Signed-off-by: Linus Torvalds --- drivers/net/e1000e/ich8lan.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c index f4b6744d71df..0b6095ba3ce9 100644 --- a/drivers/net/e1000e/ich8lan.c +++ b/drivers/net/e1000e/ich8lan.c @@ -380,6 +380,9 @@ static s32 e1000_get_variants_ich8lan(struct e1000_adapter *adapter) return 0; } +static DEFINE_MUTEX(nvm_mutex); +static pid_t nvm_owner = -1; + /** * e1000_acquire_swflag_ich8lan - Acquire software control flag * @hw: pointer to the HW structure @@ -393,6 +396,15 @@ static s32 e1000_acquire_swflag_ich8lan(struct e1000_hw *hw) u32 extcnf_ctrl; u32 timeout = PHY_CFG_TIMEOUT; + WARN_ON(preempt_count()); + + if (!mutex_trylock(&nvm_mutex)) { + WARN(1, KERN_ERR "e1000e mutex contention. Owned by pid %d\n", + nvm_owner); + mutex_lock(&nvm_mutex); + } + nvm_owner = current->pid; + while (timeout) { extcnf_ctrl = er32(EXTCNF_CTRL); extcnf_ctrl |= E1000_EXTCNF_CTRL_SWFLAG; @@ -407,6 +419,8 @@ static s32 e1000_acquire_swflag_ich8lan(struct e1000_hw *hw) if (!timeout) { hw_dbg(hw, "FW or HW has locked the resource for too long.\n"); + nvm_owner = -1; + mutex_unlock(&nvm_mutex); return -E1000_ERR_CONFIG; } @@ -428,6 +442,9 @@ static void e1000_release_swflag_ich8lan(struct e1000_hw *hw) extcnf_ctrl = er32(EXTCNF_CTRL); extcnf_ctrl &= ~E1000_EXTCNF_CTRL_SWFLAG; ew32(EXTCNF_CTRL, extcnf_ctrl); + + nvm_owner = -1; + mutex_unlock(&nvm_mutex); } /** -- cgit v1.2.3-58-ga151