ar5523: use container_of

If we want to shrink skb->cb then we'd have to see about
reducing struct ieee80211_tx_info, which gets embedded inside
skb->cb[].

It provides a scratch space to be used by wireless drivers.
ar5523 uses the maximum space available today (40 bytes), but it seems
we don't need this -- data->skb pointer seems to always point back to the
skb whose cb buffer the data structure resides, iow, given a pointer to the
embedded control buffer we can infer the skb address.

Tested-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/ath/ar5523/ar5523.c b/drivers/net/wireless/ath/ar5523/ar5523.c
index f92050617ae682e02bb48b6676a16298ae2dfa4f..5147ebe4cd05d13d12db78aacbd3081fe83a9727 100644 (file)
--- a/drivers/net/wireless/ath/ar5523/ar5523.c
+++ b/drivers/net/wireless/ath/ar5523/ar5523.c
@@ -779,8 +779,6 @@ static void ar5523_tx(struct ieee80211_hw *hw,
                ieee80211_stop_queues(hw);
        }
 
-       data->skb = skb;
-
        spin_lock_irqsave(&ar->tx_data_list_lock, flags);
        list_add_tail(&data->list, &ar->tx_queue_pending);
        spin_unlock_irqrestore(&ar->tx_data_list_lock, flags);
@@ -817,10 +815,13 @@ static void ar5523_tx_work_locked(struct ar5523 *ar)
                if (!data)
                        break;
 
-               skb = data->skb;
+               txi = container_of((void *)data, struct ieee80211_tx_info,
+                                  driver_data);
                txqid = 0;
-               txi = IEEE80211_SKB_CB(skb);
+
+               skb = container_of((void *)txi, struct sk_buff, cb);
                paylen = skb->len;
+
                urb = usb_alloc_urb(0, GFP_KERNEL);
                if (!urb) {
                        ar5523_err(ar, "Failed to allocate TX urb\n");

diff --git a/drivers/net/wireless/ath/ar5523/ar5523.h b/drivers/net/wireless/ath/ar5523/ar5523.h
index 00c6fd346d48225e92a865ff8938a1c9f921e6aa..9a322a65cdb548180a75940cb3997989226768e4 100644 (file)
--- a/drivers/net/wireless/ath/ar5523/ar5523.h
+++ b/drivers/net/wireless/ath/ar5523/ar5523.h
@@ -74,7 +74,6 @@ struct ar5523_tx_cmd {
 struct ar5523_tx_data {
        struct list_head        list;
        struct ar5523           *ar;
-       struct sk_buff          *skb;
        struct urb              *urb;
 };