mwifiex: process RX packets in SDIO IRQ thread directly

ksdioirqd has higher priority than kworker. Process RX packets
in SDIO IRQ thread (ksdioirqd/mmcX) directly instead of deferring
the work to kworker to avoid the extra latency.
This improves TCP throughput 15~20% on an ARM platform with SDIO
2.0 controller.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/main.c

@@ -282,6 +282,7 @@ exit_main_proc:
 		mwifiex_shutdown_drv(adapter);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(mwifiex_main_process);
 
 /*
  * This function frees the adapter structure.

drivers/net/wireless/mwifiex/sdio.c

@@ -905,8 +905,8 @@ static void mwifiex_interrupt_status(struct mwifiex_adapter *adapter)
 /*
  * SDIO interrupt handler.
  *
- * This function reads the interrupt status from firmware and assigns
- * the main process in workqueue which will handle the interrupt.
+ * This function reads the interrupt status from firmware and handles
+ * the interrupt in current thread (ksdioirqd) right away.
  */
 static void
 mwifiex_sdio_interrupt(struct sdio_func *func)
@@ -929,7 +929,7 @@ mwifiex_sdio_interrupt(struct sdio_func *func)
 		adapter->ps_state = PS_STATE_AWAKE;
 
 	mwifiex_interrupt_status(adapter);
-	queue_work(adapter->workqueue, &adapter->main_work);
+	mwifiex_main_process(adapter);
 }
 
 /*