From d94401742dc662747db5bb9e444d353a4feba018 Mon Sep 17 00:00:00 2001 From: Cindy H Kao Date: Fri, 23 Apr 2010 17:19:06 -0700 Subject: [PATCH] wimax/i2400m: Reset the TX FIFO indices when allocating the TX FIFO in tx_setup() This patch makes sure whenever tx_setup() is invoked during driver initialization or device reset where TX FIFO is released and re-allocated, the indices tx_in, tx_out, tx_msg_size, tx_sequence, tx_msg are properly initialized. When a device reset happens and the TX FIFO is released/re-allocated, a new block of memory may be allocated for the TX FIFO, therefore tx_msg should be cleared so that no any TX threads (tx_worker, tx) would access to the out-of-date addresses. Also, the TX threads use tx_in and tx_out to decide where to put the new host-to-device messages and from where to copy them to the device HW FIFO, these indices have to be cleared so after the TX FIFO is re-allocated during the reset, the indices both refer to the head of the FIFO, ie. a new start. The same rational applies to tx_msg_size and tx_sequence. To protect the indices from being accessed by multiple threads simultaneously, the lock tx_lock has to be obtained before the initializations and released afterwards. Signed-off-by: Cindy H Kao --- drivers/net/wimax/i2400m/tx.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/net/wimax/i2400m/tx.c b/drivers/net/wimax/i2400m/tx.c index 8561c07..21909e5 100644 --- a/drivers/net/wimax/i2400m/tx.c +++ b/drivers/net/wimax/i2400m/tx.c @@ -877,27 +877,40 @@ EXPORT_SYMBOL_GPL(i2400m_tx_msg_sent); * i2400m_tx_setup - Initialize the TX queue and infrastructure * * Make sure we reset the TX sequence to zero, as when this function - * is called, the firmware has been just restarted. + * is called, the firmware has been just restarted. Same rational + * for tx_in, tx_out, tx_msg_size and tx_msg. We reset them since + * the memory for TX queue is reallocated. */ int i2400m_tx_setup(struct i2400m *i2400m) { - int result; + int result = 0; + void *tx_buf; + unsigned long flags; /* Do this here only once -- can't do on * i2400m_hard_start_xmit() as we'll cause race conditions if * the WS was scheduled on another CPU */ INIT_WORK(&i2400m->wake_tx_ws, i2400m_wake_tx_work); - i2400m->tx_sequence = 0; + tx_buf = kmalloc(I2400M_TX_BUF_SIZE, GFP_ATOMIC); + if (tx_buf == NULL) { + result = -ENOMEM; + goto error_kmalloc; + } + /* Warn if the calculated buffer size exceeds I2400M_TX_BUF_SIZE. */ BUILD_BUG_ON(I2400M_TX_PDU_TOTAL_SIZE > I2400M_TX_BUF_SIZE); - i2400m->tx_buf = kmalloc(I2400M_TX_BUF_SIZE, GFP_KERNEL); - if (i2400m->tx_buf == NULL) - result = -ENOMEM; - else - result = 0; + spin_lock_irqsave(&i2400m->tx_lock, flags); + i2400m->tx_sequence = 0; + i2400m->tx_in = 0; + i2400m->tx_out = 0; + i2400m->tx_msg_size = 0; + i2400m->tx_msg = NULL; + i2400m->tx_buf = tx_buf; + spin_unlock_irqrestore(&i2400m->tx_lock, flags); /* Huh? the bus layer has to define this... */ BUG_ON(i2400m->bus_tx_block_size == 0); +error_kmalloc: return result; } -- 2.7.4