wimax/i2400m: fix oops in TX when tearing down the device

All the entry points into the TX module should check if the device has
been torn down. Otherwise, when the device resets or shuts down, there
are windows when a call to i2400m_tx*() will oops the system.

For that, make i2400m_tx_release() set i2400m->tx_buf to NULL under
the tx_lock. Then, any entry point [i2400m_tx(), _tx_msg_sent(),
_tx_msg_get()] will check for i2400m->tx_buf to be NULL and exit
gracefully.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>

diff --git a/drivers/net/wimax/i2400m/sdio-tx.c b/drivers/net/wimax/i2400m/sdio-tx.c
index 5105a5ebc44f988d8381bc5327f5b4dec4a9ea97..de66d068c9cbf2717a54c15254dfcfa96ffaac26 100644 (file)
--- a/drivers/net/wimax/i2400m/sdio-tx.c
+++ b/drivers/net/wimax/i2400m/sdio-tx.c
@@ -149,5 +149,8 @@ int i2400ms_tx_setup(struct i2400ms *i2400ms)
 
 void i2400ms_tx_release(struct i2400ms *i2400ms)
 {
-       destroy_workqueue(i2400ms->tx_workqueue);
+       if (i2400ms->tx_workqueue) {
+               destroy_workqueue(i2400ms->tx_workqueue);
+               i2400ms->tx_workqueue = NULL;
+       }
 }

diff --git a/drivers/net/wimax/i2400m/tx.c b/drivers/net/wimax/i2400m/tx.c
index 8c2080248aec3538b8edf78d3d599a674243e4e8..54480e8947f1a6acd0b306798ad25b81c2b76fd9 100644 (file)
--- a/drivers/net/wimax/i2400m/tx.c
+++ b/drivers/net/wimax/i2400m/tx.c
@@ -642,6 +642,9 @@ int i2400m_tx(struct i2400m *i2400m, const void *buf, size_t buf_len,
         * current one is out of payload slots or we have a singleton,
         * close it and start a new one */
        spin_lock_irqsave(&i2400m->tx_lock, flags);
+       result = -ESHUTDOWN;
+       if (i2400m->tx_buf == NULL)
+               goto error_tx_new;
 try_new:
        if (unlikely(i2400m->tx_msg == NULL))
                i2400m_tx_new(i2400m);
@@ -697,7 +700,10 @@ try_new:
        }
 error_tx_new:
        spin_unlock_irqrestore(&i2400m->tx_lock, flags);
-       i2400m->bus_tx_kick(i2400m);    /* always kick, might free up space */
+       /* kick in most cases, except when the TX subsys is down, as
+        * it might free space */
+       if (likely(result != -ESHUTDOWN))
+               i2400m->bus_tx_kick(i2400m);
        d_fnend(3, dev, "(i2400m %p skb %p [%zu bytes] pt %u) = %d\n",
                i2400m, buf, buf_len, pl_type, result);
        return result;
@@ -740,6 +746,9 @@ struct i2400m_msg_hdr *i2400m_tx_msg_get(struct i2400m *i2400m,
 
        d_fnstart(3, dev, "(i2400m %p bus_size %p)\n", i2400m, bus_size);
        spin_lock_irqsave(&i2400m->tx_lock, flags);
+       tx_msg_moved = NULL;
+       if (i2400m->tx_buf == NULL)
+               goto out_unlock;
 skip:
        tx_msg_moved = NULL;
        if (i2400m->tx_in == i2400m->tx_out) {  /* Empty FIFO? */
@@ -829,6 +838,8 @@ void i2400m_tx_msg_sent(struct i2400m *i2400m)
 
        d_fnstart(3, dev, "(i2400m %p)\n", i2400m);
        spin_lock_irqsave(&i2400m->tx_lock, flags);
+       if (i2400m->tx_buf == NULL)
+               goto out_unlock;
        i2400m->tx_out += i2400m->tx_msg_size;
        d_printf(2, dev, "TX: sent %zu b\n", (size_t) i2400m->tx_msg_size);
        i2400m->tx_msg_size = 0;
@@ -837,6 +848,7 @@ void i2400m_tx_msg_sent(struct i2400m *i2400m)
        n = i2400m->tx_out / I2400M_TX_BUF_SIZE;
        i2400m->tx_out %= I2400M_TX_BUF_SIZE;
        i2400m->tx_in -= n * I2400M_TX_BUF_SIZE;
+out_unlock:
        spin_unlock_irqrestore(&i2400m->tx_lock, flags);
        d_fnend(3, dev, "(i2400m %p) = void\n", i2400m);
 }
@@ -876,5 +888,9 @@ int i2400m_tx_setup(struct i2400m *i2400m)
  */
 void i2400m_tx_release(struct i2400m *i2400m)
 {
+       unsigned long flags;
+       spin_lock_irqsave(&i2400m->tx_lock, flags);
        kfree(i2400m->tx_buf);
+       i2400m->tx_buf = NULL;
+       spin_unlock_irqrestore(&i2400m->tx_lock, flags);
 }