PWN-Hunter/android_kernel_xiaomi_sdm845
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mwl8k: minor transmit quiescing rework

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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 <buytenh@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Lennert Buytenhek 2009-10-22 20:19:37 +02:00 committed by John W. Linville
parent c2c357ce30
commit 88de754ad5
1 changed files with 15 additions and 22 deletions
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37
drivers/net/wireless/mwl8k.c
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@ -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)