2021-04-05 09:12:05

by Christophe JAILLET

Subject: [PATCH] rtl8xxxu: Simplify locking of a skb list accesses

The 'c2hcmd_lock' spinlock is only used to protect some __skb_queue_tail()
and __skb_dequeue() calls.
Use the lock provided in the skb itself and call skb_queue_tail() and
skb_dequeue(). These functions already include the correct locking.

Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h | 1 -
drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 11 ++---------
2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
index d6d1be4169e5..d1a566cc0c9e 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
@@ -1391,7 +1391,6 @@ struct rtl8xxxu_priv {
struct delayed_work ra_watchdog;
struct work_struct c2hcmd_work;
struct sk_buff_head c2hcmd_queue;
- spinlock_t c2hcmd_lock;
struct rtl8xxxu_btcoex bt_coex;
struct rtl8xxxu_ra_report ra_report;
};
diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
index 5cd7ef3625c5..0eba42f2a66c 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -5423,7 +5423,6 @@ static void rtl8xxxu_c2hcmd_callback(struct work_struct *work)
struct rtl8xxxu_priv *priv;
struct rtl8723bu_c2h *c2h;
struct sk_buff *skb = NULL;
- unsigned long flags;
u8 bt_info = 0;
struct rtl8xxxu_btcoex *btcoex;
struct rtl8xxxu_ra_report *rarpt;
@@ -5439,9 +5438,7 @@ static void rtl8xxxu_c2hcmd_callback(struct work_struct *work)
goto out;

while (!skb_queue_empty(&priv->c2hcmd_queue)) {
- spin_lock_irqsave(&priv->c2hcmd_lock, flags);
- skb = __skb_dequeue(&priv->c2hcmd_queue);
- spin_unlock_irqrestore(&priv->c2hcmd_lock, flags);
+ skb = skb_dequeue(&priv->c2hcmd_queue);

c2h = (struct rtl8723bu_c2h *)skb->data;

@@ -5499,7 +5496,6 @@ static void rtl8723bu_handle_c2h(struct rtl8xxxu_priv *priv,
struct rtl8723bu_c2h *c2h = (struct rtl8723bu_c2h *)skb->data;
struct device *dev = &priv->udev->dev;
int len;
- unsigned long flags;

len = skb->len - 2;

@@ -5538,9 +5534,7 @@ static void rtl8723bu_handle_c2h(struct rtl8xxxu_priv *priv,
break;
}

- spin_lock_irqsave(&priv->c2hcmd_lock, flags);
- __skb_queue_tail(&priv->c2hcmd_queue, skb);
- spin_unlock_irqrestore(&priv->c2hcmd_lock, flags);
+ skb_queue_tail(&priv->c2hcmd_queue, skb);

schedule_work(&priv->c2hcmd_work);
}
@@ -6606,7 +6600,6 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
spin_lock_init(&priv->rx_urb_lock);
INIT_WORK(&priv->rx_urb_wq, rtl8xxxu_rx_urb_work);
INIT_DELAYED_WORK(&priv->ra_watchdog, rtl8xxxu_watchdog_callback);
- spin_lock_init(&priv->c2hcmd_lock);
INIT_WORK(&priv->c2hcmd_work, rtl8xxxu_c2hcmd_callback);
skb_queue_head_init(&priv->c2hcmd_queue);

--
2.27.0

2021-04-17 17:55:58

by Kalle Valo

Subject: Re: [PATCH] rtl8xxxu: Simplify locking of a skb list accesses

Christophe JAILLET <[email protected]> wrote:

> The 'c2hcmd_lock' spinlock is only used to protect some __skb_queue_tail()
> and __skb_dequeue() calls.
> Use the lock provided in the skb itself and call skb_queue_tail() and
> skb_dequeue(). These functions already include the correct locking.
>
> Signed-off-by: Christophe JAILLET <[email protected]>

Patch applied to wireless-drivers-next.git, thanks.

431eb49e87ed rtl8xxxu: Simplify locking of a skb list accesses

--
https://patchwork.kernel.org/project/linux-wireless/patch/8bcec6429615aeb498482dc7e1955ce09b456585.1617613700.git.christophe.jaillet@wanadoo.fr/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches