Return-path: Received: from fw.wantstofly.org ([80.101.37.227]:49171 "EHLO mail.wantstofly.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756524AbZJVShK (ORCPT ); Thu, 22 Oct 2009 14:37:10 -0400 Date: Thu, 22 Oct 2009 20:19:37 +0200 From: Lennert Buytenhek To: linux-wireless@vger.kernel.org Subject: [PATCH 03/28] mwl8k: minor transmit quiescing rework Message-ID: <20091022181937.GE1583@mail.wantstofly.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-wireless-owner@vger.kernel.org List-ID: Minor changes to the transmit quiescing logic: - Clarify the locking rules for ->tx_wait: only the holder of fw_mutex can wait for the TX path to become idle, but tx_wait itself is read and cleared by the TX reclaim tasklet under tx_lock. - Inline mwl8k_txq_busy() in its callers. - There's no need to kick the transmitter again in mwl8k_tx_wait_empty(), since it will have been kicked when the packets currently in the TX ring were added to it. - If the TX ring didn't drain in time, run mwl8k_scan_tx_ring() after reading priv->pending_pkts without dropping tx_lock in between. Signed-off-by: Lennert Buytenhek --- drivers/net/wireless/mwl8k.c | 37 +++++++++++++++---------------------- 1 files changed, 15 insertions(+), 22 deletions(-) diff --git a/drivers/net/wireless/mwl8k.c b/drivers/net/wireless/mwl8k.c index 252ef9c..ba7b8ef 100644 --- a/drivers/net/wireless/mwl8k.c +++ b/drivers/net/wireless/mwl8k.c @@ -142,12 +142,14 @@ struct mwl8k_priv { struct mutex fw_mutex; struct task_struct *fw_mutex_owner; int fw_mutex_depth; - struct completion *tx_wait; struct completion *hostcmd_wait; /* lock held over TX and TX reap */ spinlock_t tx_lock; + /* TX quiesce completion, protected by fw_mutex and tx_lock */ + struct completion *tx_wait; + struct ieee80211_vif *vif; struct ieee80211_channel *current_channel; @@ -1064,11 +1066,6 @@ static inline void mwl8k_tx_start(struct mwl8k_priv *priv) ioread32(priv->regs + MWL8K_HIU_INT_CODE); } -static inline int mwl8k_txq_busy(struct mwl8k_priv *priv) -{ - return priv->pending_tx_pkts; -} - struct mwl8k_txq_info { u32 fw_owned; u32 drv_owned; @@ -1088,7 +1085,6 @@ static int mwl8k_scan_tx_ring(struct mwl8k_priv *priv, memset(txinfo, 0, MWL8K_TX_QUEUES * sizeof(struct mwl8k_txq_info)); - spin_lock_bh(&priv->tx_lock); for (count = 0; count < MWL8K_TX_QUEUES; count++) { txq = priv->txq + count; txinfo[count].len = txq->tx_stats.len; @@ -1107,30 +1103,26 @@ static int mwl8k_scan_tx_ring(struct mwl8k_priv *priv, txinfo[count].unused++; } } - spin_unlock_bh(&priv->tx_lock); return ndescs; } /* - * Must be called with hw->fw_mutex held and tx queues stopped. + * Must be called with priv->fw_mutex held and tx queues stopped. */ static int mwl8k_tx_wait_empty(struct ieee80211_hw *hw) { struct mwl8k_priv *priv = hw->priv; - DECLARE_COMPLETION_ONSTACK(cmd_wait); + DECLARE_COMPLETION_ONSTACK(tx_wait); u32 count; unsigned long timeout; might_sleep(); spin_lock_bh(&priv->tx_lock); - count = mwl8k_txq_busy(priv); - if (count) { - priv->tx_wait = &cmd_wait; - if (priv->radio_on) - mwl8k_tx_start(priv); - } + count = priv->pending_tx_pkts; + if (count) + priv->tx_wait = &tx_wait; spin_unlock_bh(&priv->tx_lock); if (count) { @@ -1138,20 +1130,20 @@ static int mwl8k_tx_wait_empty(struct ieee80211_hw *hw) int index; int newcount; - timeout = wait_for_completion_timeout(&cmd_wait, + timeout = wait_for_completion_timeout(&tx_wait, msecs_to_jiffies(5000)); if (timeout) return 0; spin_lock_bh(&priv->tx_lock); priv->tx_wait = NULL; - newcount = mwl8k_txq_busy(priv); + newcount = priv->pending_tx_pkts; + mwl8k_scan_tx_ring(priv, txinfo); spin_unlock_bh(&priv->tx_lock); printk(KERN_ERR "%s(%u) TIMEDOUT:5000ms Pend:%u-->%u\n", __func__, __LINE__, count, newcount); - mwl8k_scan_tx_ring(priv, txinfo); for (index = 0; index < MWL8K_TX_QUEUES; index++) printk(KERN_ERR "TXQ:%u L:%u H:%u T:%u FW:%u " "DRV:%u U:%u\n", @@ -2397,7 +2389,7 @@ static irqreturn_t mwl8k_interrupt(int irq, void *dev_id) if (status & MWL8K_A2H_INT_QUEUE_EMPTY) { if (!mutex_is_locked(&priv->fw_mutex) && - priv->radio_on && mwl8k_txq_busy(priv)) + priv->radio_on && priv->pending_tx_pkts) mwl8k_tx_start(priv); } @@ -2800,7 +2792,7 @@ static void mwl8k_tx_reclaim_handler(unsigned long data) for (i = 0; i < MWL8K_TX_QUEUES; i++) mwl8k_txq_reclaim(hw, i, 0); - if (priv->tx_wait != NULL && mwl8k_txq_busy(priv) == 0) { + if (priv->tx_wait != NULL && !priv->pending_tx_pkts) { complete(priv->tx_wait); priv->tx_wait = NULL; } @@ -2932,11 +2924,12 @@ static int __devinit mwl8k_probe(struct pci_dev *pdev, mutex_init(&priv->fw_mutex); priv->fw_mutex_owner = NULL; priv->fw_mutex_depth = 0; - priv->tx_wait = NULL; priv->hostcmd_wait = NULL; spin_lock_init(&priv->tx_lock); + priv->tx_wait = NULL; + for (i = 0; i < MWL8K_TX_QUEUES; i++) { rc = mwl8k_txq_init(hw, i); if (rc) -- 1.5.6.4