Merge branch 'for-davem' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next

John W. Linville says:

====================
Please accept this batch of updates intended for the 3.12 stream.

For the mac80211 bits, Johannes says this:

"This time I have various improvements all over the place: IBSS, mesh,
testmode, AP client powersave handling, one of the rare rfkill patches
and some code cleanup."

Also for mac80211:

"And I also have some more changes for -next, just a few small fixes and
improvements, nothing really stands out."

And for iwlwifi:

"This time I have some powersave work (notably uAPSD support), CQM
offloads, support for a new firmware API and various code cleanups."

Regarding the Bluetooth bits, Gustavo says:

"Patches to 3.12, here we have:

* implementation of a proper tty_port for RFCOMM devices, this fixes some
issues people were seeing lately in the kernel.
* Add voice_setting option for SCO, it is used for SCO Codec selection
* bugfixes, small improvements and clean ups"

For the NFC bits, Samuel says:

"With this one we have:

- A few pn533 improvements and minor fixes. Testing our pn533 driver
  against Google's NCI stack triggered a few issues that we fixed now.
  We also added Tx fragmentation support to this driver.

- More NFC secure element handling. We added a GET_SE netlink command
  for getting all the discovered secure elements, and we defined 2
  additional secure element netlink event (transaction and connectivity).
  We also fixed a couple of typos and copy-paste bugs from the secure
  element handling code.

- Firmware download support for the pn544 driver. This chipset can enter a
  special mode where it's waiting for firmware blobs to replace the
  already flashed one. We now support that mode."

With repect to the ath tree, Kalle says:

"New features in ath10k are rx/tx checsumming in hw and survey scan
implemented by Michal. Also he made fixes to different areas of the
driver, most notable being fixing the case when using two streams and
reducing the number of interface combinations to avoid firmware crashes.
Bartosz did a clean related to how we handle SoC power save in PCI
layer.

For ath6kl Mohammed and Vasanth sent each a patch to fix two infrequent
crashes."

I also pulled the wireless tree into wireless-next to support a
request from Johannes.  On top of all that, there are the usual
sort of driver updates.  The mwifiex, brcmfmac, brcmsmac, ath9k,
and rt2x00 drivers all get some attention, as does the bcma bus and
a few other random bits here and there.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 25 insertions, 13 deletions

diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c
index 011167c22da8..f45eb29c2ede 100644
--- a/drivers/net/wireless/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/tx.c
@@ -65,18 +65,30 @@
  ***************************************************/
 static int iwl_queue_space(const struct iwl_queue *q)
 {
-	int s = q->read_ptr - q->write_ptr;
-
-	if (q->read_ptr > q->write_ptr)
-		s -= q->n_bd;
-
-	if (s <= 0)
-		s += q->n_window;
-	/* keep some reserve to not confuse empty and full situations */
-	s -= 2;
-	if (s < 0)
-		s = 0;
-	return s;
+	unsigned int max;
+	unsigned int used;
+
+	/*
+	 * To avoid ambiguity between empty and completely full queues, there
+	 * should always be less than q->n_bd elements in the queue.
+	 * If q->n_window is smaller than q->n_bd, there is no need to reserve
+	 * any queue entries for this purpose.
+	 */
+	if (q->n_window < q->n_bd)
+		max = q->n_window;
+	else
+		max = q->n_bd - 1;
+
+	/*
+	 * q->n_bd is a power of 2, so the following is equivalent to modulo by
+	 * q->n_bd and is well defined for negative dividends.
+	 */
+	used = (q->write_ptr - q->read_ptr) & (q->n_bd - 1);
+
+	if (WARN_ON(used > max))
+		return 0;
+
+	return max - used;
 }
 
 /*
@@ -826,7 +838,7 @@ static int iwl_pcie_tx_alloc(struct iwl_trans *trans)
 				  sizeof(struct iwl_txq), GFP_KERNEL);
 	if (!trans_pcie->txq) {
 		IWL_ERR(trans, "Not enough memory for txq\n");
-		ret = ENOMEM;
+		ret = -ENOMEM;
 		goto error;
 	}