staging: ath6kl: Fixing a race condition during initialization

The commit fixes a race condition in the initialization portion of the
driver. The problem was observed while testing with the kernel in the
staging-next tree. The wait on the ready event is signalled prematurely
before setting the arVersion.wlan_ver and arVersion.abi_ver. The code
waiting on this semaphore checks for the validity of these values and
hence may proceed with an un-updated values of these fields. The wakeup
signal is now sent after these values are set.

Signed-off-by: Vipin Mehta <vmehta@atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/ath6kl/os/linux/ar6000_drv.c b/drivers/staging/ath6kl/os/linux/ar6000_drv.c
index c7922c9ff233ce8c1d5b558b384bff7960c1ba64..daba6e4cb9d8bf6a13f8f9294964d868190eef9f 100644 (file)
--- a/drivers/staging/ath6kl/os/linux/ar6000_drv.c
+++ b/drivers/staging/ath6kl/os/linux/ar6000_drv.c
@@ -4170,8 +4170,6 @@ ar6000_ready_event(void *devt, A_UINT8 *datap, A_UINT8 phyCap, A_UINT32 sw_ver,
     AR_SOFTC_T *ar = (AR_SOFTC_T *)devt;
     struct net_device *dev = ar->arNetDev;
 
-    ar->arWmiReady = TRUE;
-    wake_up(&arEvent);
     A_MEMCPY(dev->dev_addr, datap, AR6000_ETH_ADDR_LEN);
     AR_DEBUG_PRINTF(ATH_DEBUG_INFO,("mac address = %2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n",
         dev->dev_addr[0], dev->dev_addr[1],
@@ -4182,6 +4180,10 @@ ar6000_ready_event(void *devt, A_UINT8 *datap, A_UINT8 phyCap, A_UINT32 sw_ver,
     ar->arVersion.wlan_ver = sw_ver;
     ar->arVersion.abi_ver = abi_ver;
 
+    /* Indicate to the waiting thread that the ready event was received */
+    ar->arWmiReady = TRUE;
+    wake_up(&arEvent);
+
 #if WLAN_CONFIG_IGNORE_POWER_SAVE_FAIL_EVENT_DURING_SCAN
     wmi_pmparams_cmd(ar->arWmi, 0, 1, 0, 0, 1, IGNORE_POWER_SAVE_FAIL_EVENT_DURING_SCAN);
 #endif