diff mbox

[2/7] staging: wilc1000: Replace semaphore txq_add_to_head_cs with mutex

Message ID 1465814259-3009-3-git-send-email-binoy.jayan@linaro.org
State Superseded
Headers show

Commit Message

Binoy Jayan June 13, 2016, 10:37 a.m. UTC 
The semaphore 'txq_add_to_head_cs' is a simple mutex, so it should be
written as one. Semaphores are going away in the future. Also, removing
the timeout scenario as the error handling code does not propagate the
timeout properly.

Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org>

---
 drivers/staging/wilc1000/linux_wlan.c         |  4 ++--
 drivers/staging/wilc1000/wilc_wfi_netdevice.h |  3 ++-
 drivers/staging/wilc1000/wilc_wlan.c          | 11 ++++-------
 3 files changed, 8 insertions(+), 10 deletions(-)

-- 
2.7.4

Comments

Arnd Bergmann June 13, 2016, 1:20 p.m. UTC | #1 
On Monday, June 13, 2016 4:07:34 PM CEST Binoy Jayan wrote:
> The semaphore 'txq_add_to_head_cs' is a simple mutex, so it should be

> written as one. Semaphores are going away in the future.


Looks good to me.

> Also, removing

> the timeout scenario as the error handling code does not propagate the

> timeout properly.


Good catch! I guess wilc_wlan_handle_txq() running into a timeout 
would end putting the semaphore in a state in which we never again
block on it because the count is now one higher than it should be.

	Arnd
diff mbox

Patch

diff --git a/drivers/staging/wilc1000/linux_wlan.c b/drivers/staging/wilc1000/linux_wlan.c
index 90f906d..a933551 100644
--- a/drivers/staging/wilc1000/linux_wlan.c
+++ b/drivers/staging/wilc1000/linux_wlan.c
@@ -20,7 +20,7 @@ 
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
-
+#include <linux/mutex.h>
 #include <linux/semaphore.h>
 #include <linux/completion.h>
 
@@ -679,7 +679,7 @@  static int wlan_init_locks(struct net_device *dev)
 	mutex_init(&wl->rxq_cs);
 
 	spin_lock_init(&wl->txq_spinlock);
-	sema_init(&wl->txq_add_to_head_cs, 1);
+	mutex_init(&wl->txq_add_to_head_cs);
 
 	init_completion(&wl->txq_event);
 
diff --git a/drivers/staging/wilc1000/wilc_wfi_netdevice.h b/drivers/staging/wilc1000/wilc_wfi_netdevice.h
index 12d7c7b..239cd43 100644
--- a/drivers/staging/wilc1000/wilc_wfi_netdevice.h
+++ b/drivers/staging/wilc1000/wilc_wfi_netdevice.h
@@ -43,6 +43,7 @@ 
 #include "wilc_wlan.h"
 #include <linux/wireless.h>
 #include <linux/completion.h>
+#include <linux/mutex.h>
 
 #define FLOW_CONTROL_LOWER_THRESHOLD	128
 #define FLOW_CONTROL_UPPER_THRESHOLD	256
@@ -171,7 +172,7 @@  struct wilc {
 	struct wilc_vif *vif[NUM_CONCURRENT_IFC];
 	u8 open_ifcs;
 
-	struct semaphore txq_add_to_head_cs;
+	struct mutex txq_add_to_head_cs;
 	spinlock_t txq_spinlock;
 
 	struct mutex rxq_cs;
diff --git a/drivers/staging/wilc1000/wilc_wlan.c b/drivers/staging/wilc1000/wilc_wlan.c
index 1a57135..9afbe8d 100644
--- a/drivers/staging/wilc1000/wilc_wlan.c
+++ b/drivers/staging/wilc1000/wilc_wlan.c
@@ -99,9 +99,7 @@  static int wilc_wlan_txq_add_to_head(struct wilc_vif *vif,
 	unsigned long flags;
 	struct wilc *wilc = vif->wilc;
 
-	if (wilc_lock_timeout(wilc, &wilc->txq_add_to_head_cs,
-				    CFG_PKTS_TIMEOUT))
-		return -1;
+	mutex_lock(&wilc->txq_add_to_head_cs);
 
 	spin_lock_irqsave(&wilc->txq_spinlock, flags);
 
@@ -119,7 +117,7 @@  static int wilc_wlan_txq_add_to_head(struct wilc_vif *vif,
 	wilc->txq_entries += 1;
 
 	spin_unlock_irqrestore(&wilc->txq_spinlock, flags);
-	up(&wilc->txq_add_to_head_cs);
+	mutex_unlock(&wilc->txq_add_to_head_cs);
 	complete(&wilc->txq_event);
 
 	return 0;
@@ -573,8 +571,7 @@  int wilc_wlan_handle_txq(struct net_device *dev, u32 *txq_count)
 		if (wilc->quit)
 			break;
 
-		wilc_lock_timeout(wilc, &wilc->txq_add_to_head_cs,
-					CFG_PKTS_TIMEOUT);
+		mutex_lock(&wilc->txq_add_to_head_cs);
 		wilc_wlan_txq_filter_dup_tcp_ack(dev);
 		tqe = wilc_wlan_txq_get_first(wilc);
 		i = 0;
@@ -755,7 +752,7 @@  _end_:
 		if (ret != 1)
 			break;
 	} while (0);
-	up(&wilc->txq_add_to_head_cs);
+	mutex_unlock(&wilc->txq_add_to_head_cs);
 
 	wilc->txq_exit = 1;
 	*txq_count = wilc->txq_entries;