ath9k_htc: Simplify RX URB management

This patch introduces the usage of URB anchors,
thus reducing a large amount of code dealing with
URB maintenance within the driver. The RX callback now
takes care of freeing the SKB associated with each URB.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 50 insertions, 82 deletions

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index fc4f6e8c9ef3..e584a2912993 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -299,6 +299,8 @@ static int hif_usb_send(void *hif_handle, u8 pipe_id, struct sk_buff *skb,
                 ret = hif_usb_send_regout(hif_dev, skb);
                 break;
         default:
+                dev_err(&hif_dev->udev->dev,
+                        "ath9k_htc: Invalid TX pipe: %d\n", pipe_id);
                 ret = -EINVAL;
                 break;
         }
@@ -408,14 +410,11 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
                         }
                 } else {
                         RX_STAT_INC(skb_dropped);
-                        dev_kfree_skb_any(skb);
                         return;
                 }
         }
 
 err:
-        dev_kfree_skb_any(skb);
-
         for (i = 0; i < pool_index; i++) {
                 ath9k_htc_rx_msg(hif_dev->htc_handle, skb_pool[i],
                                  skb_pool[i]->len, USB_WLAN_RX_PIPE);
@@ -426,11 +425,13 @@ err:
 static void ath9k_hif_usb_rx_cb(struct urb *urb)
 {
         struct sk_buff *skb = (struct sk_buff *) urb->context;
-        struct sk_buff *nskb;
         struct hif_device_usb *hif_dev = (struct hif_device_usb *)
                 usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0));
         int ret;
 
+        if (!skb)
+                return;
+
         if (!hif_dev)
                 goto free;
 
@@ -448,34 +449,19 @@ static void ath9k_hif_usb_rx_cb(struct urb *urb)
 
         if (likely(urb->actual_length != 0)) {
                 skb_put(skb, urb->actual_length);
-
-                nskb = __dev_alloc_skb(MAX_RX_BUF_SIZE, GFP_ATOMIC);
-                if (!nskb)
-                        goto resubmit;
-
-                usb_fill_bulk_urb(urb, hif_dev->udev,
-                                  usb_rcvbulkpipe(hif_dev->udev,
-                                                  USB_WLAN_RX_PIPE),
-                                  nskb->data, MAX_RX_BUF_SIZE,
-                                  ath9k_hif_usb_rx_cb, nskb);
-
-                ret = usb_submit_urb(urb, GFP_ATOMIC);
-                if (ret) {
-                        dev_kfree_skb_any(nskb);
-                        goto free;
-                }
-
                 ath9k_hif_usb_rx_stream(hif_dev, skb);
-                return;
         }
 
 resubmit:
         skb_reset_tail_pointer(skb);
         skb_trim(skb, 0);
 
+        usb_anchor_urb(urb, &hif_dev->rx_submitted);
         ret = usb_submit_urb(urb, GFP_ATOMIC);
-        if (ret)
+        if (ret) {
+                usb_unanchor_urb(urb);
                 goto free;
+        }
 
         return;
 free:
@@ -490,6 +476,9 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb)
                 usb_get_intfdata(usb_ifnum_to_if(urb->dev, 0));
         int ret;
 
+        if (!skb)
+                return;
+
         if (!hif_dev)
                 goto free;
 
@@ -540,6 +529,7 @@ resubmit:
         return;
 free:
         dev_kfree_skb_any(skb);
+        urb->context = NULL;
 }
 
 static void ath9k_hif_usb_dealloc_tx_urbs(struct hif_device_usb *hif_dev)
@@ -609,78 +599,59 @@ err:
         return -ENOMEM;
 }
 
-static void ath9k_hif_usb_dealloc_rx_skbs(struct hif_device_usb *hif_dev)
-{
-        int i;
-
-        for (i = 0; i < MAX_RX_URB_NUM; i++) {
-                if (hif_dev->wlan_rx_data_urb[i]) {
-                        if (hif_dev->wlan_rx_data_urb[i]->transfer_buffer)
-                                dev_kfree_skb_any((void *)
-                                          hif_dev->wlan_rx_data_urb[i]->context);
-                }
-        }
-}
-
 static void ath9k_hif_usb_dealloc_rx_urbs(struct hif_device_usb *hif_dev)
 {
-        int i;
-
-        for (i = 0; i < MAX_RX_URB_NUM; i++) {
-                if (hif_dev->wlan_rx_data_urb[i]) {
-                        usb_kill_urb(hif_dev->wlan_rx_data_urb[i]);
-                        usb_free_urb(hif_dev->wlan_rx_data_urb[i]);
-                        hif_dev->wlan_rx_data_urb[i] = NULL;
-                }
-        }
-}
-
-static int ath9k_hif_usb_prep_rx_urb(struct hif_device_usb *hif_dev,
-                                     struct urb *urb)
-{
-        struct sk_buff *skb;
-
-        skb = __dev_alloc_skb(MAX_RX_BUF_SIZE, GFP_KERNEL);
-        if (!skb)
-                return -ENOMEM;
-
-        usb_fill_bulk_urb(urb, hif_dev->udev,
-                          usb_rcvbulkpipe(hif_dev->udev, USB_WLAN_RX_PIPE),
-                          skb->data, MAX_RX_BUF_SIZE,
-                          ath9k_hif_usb_rx_cb, skb);
-        return 0;
+        usb_kill_anchored_urbs(&hif_dev->rx_submitted);
 }
 
 static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)
 {
+        struct urb *urb = NULL;
+        struct sk_buff *skb = NULL;
         int i, ret;
 
+        init_usb_anchor(&hif_dev->rx_submitted);
+
         for (i = 0; i < MAX_RX_URB_NUM; i++) {
 
                 /* Allocate URB */
-                hif_dev->wlan_rx_data_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
-                if (hif_dev->wlan_rx_data_urb[i] == NULL) {
+                urb = usb_alloc_urb(0, GFP_KERNEL);
+                if (urb == NULL) {
                         ret = -ENOMEM;
-                        goto err_rx_urb;
+                        goto err_urb;
                 }
 
                 /* Allocate buffer */
-                ret = ath9k_hif_usb_prep_rx_urb(hif_dev,
-                                                hif_dev->wlan_rx_data_urb[i]);
-                if (ret)
-                        goto err_rx_urb;
+                skb = __dev_alloc_skb(MAX_RX_BUF_SIZE, GFP_KERNEL);
+                if (!skb) {
+                        ret = -ENOMEM;
+                        goto err_skb;
+                }
 
-                /* Submit URB */
-                ret = usb_submit_urb(hif_dev->wlan_rx_data_urb[i], GFP_KERNEL);
-                if (ret)
-                        goto err_rx_urb;
+                usb_fill_bulk_urb(urb, hif_dev->udev,
+                                  usb_rcvbulkpipe(hif_dev->udev,
+                                                  USB_WLAN_RX_PIPE),
+                                  skb->data, MAX_RX_BUF_SIZE,
+                                  ath9k_hif_usb_rx_cb, skb);
 
+                /* Anchor URB */
+                usb_anchor_urb(urb, &hif_dev->rx_submitted);
+
+                /* Submit URB */
+                ret = usb_submit_urb(urb, GFP_KERNEL);
+                if (ret) {
+                        usb_unanchor_urb(urb);
+                        goto err_submit;
+                }
         }
 
         return 0;
 
-err_rx_urb:
-        ath9k_hif_usb_dealloc_rx_skbs(hif_dev);
+err_submit:
+        dev_kfree_skb_any(skb);
+err_skb:
+        usb_free_urb(urb);
+err_urb:
         ath9k_hif_usb_dealloc_rx_urbs(hif_dev);
         return ret;
 }
@@ -689,6 +660,8 @@ static void ath9k_hif_usb_dealloc_reg_in_urb(struct hif_device_usb *hif_dev)
 {
         if (hif_dev->reg_in_urb) {
                 usb_kill_urb(hif_dev->reg_in_urb);
+                if (hif_dev->reg_in_urb->context)
+                        dev_kfree_skb_any((void *)hif_dev->reg_in_urb->context);
                 usb_free_urb(hif_dev->reg_in_urb);
                 hif_dev->reg_in_urb = NULL;
         }
@@ -712,12 +685,10 @@ static int ath9k_hif_usb_alloc_reg_in_urb(struct hif_device_usb *hif_dev)
                          ath9k_hif_usb_reg_in_cb, skb, 1);
 
         if (usb_submit_urb(hif_dev->reg_in_urb, GFP_KERNEL) != 0)
-                goto err_skb;
+                goto err;
 
         return 0;
 
-err_skb:
-        dev_kfree_skb_any(skb);
 err:
         ath9k_hif_usb_dealloc_reg_in_urb(hif_dev);
         return -ENOMEM;
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.h b/drivers/net/wireless/ath/ath9k/hif_usb.h
index 7cc3762a6789..ea9257bdc411 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.h
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.h
@@ -85,18 +85,15 @@ struct hif_device_usb {
         struct usb_interface *interface;
         const struct firmware *firmware;
         struct htc_target *htc_handle;
-        u8 flags;
-
         struct hif_usb_tx tx;
-
-        struct urb *wlan_rx_data_urb[MAX_RX_URB_NUM];
         struct urb *reg_in_urb;
-
+        struct usb_anchor rx_submitted;
         struct sk_buff *remain_skb;
         int rx_remain_len;
         int rx_pkt_len;
         int rx_transfer_len;
         int rx_pad_len;
+        u8 flags; /* HIF_USB_* */
 };
 
 int ath9k_hif_usb_init(void);