brcmfmac: fix race condition for rx and tx data.

On both rx and tx there is was a race condition on the queueing
of usb requests. When for example frame gets submitted it is
possible that complete function gets called even before
usb_submit_urb() returns. As a result it is possible that usb
requests get losts, which was noticed on OMAP4 pandaboard
platform. This patch fixes the race condition.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
index 8ea2db7326b..58f89fa9c9f 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
@@ -550,6 +550,7 @@ static void brcmf_usb_rx_complete(struct urb *urb)
                 if (brcmf_proto_hdrpull(devinfo->dev, &ifidx, skb) != 0) {
                         brcmf_dbg(ERROR, "rx protocol error\n");
                         brcmu_pkt_buf_free_skb(skb);
+                        brcmf_usb_enq(devinfo, &devinfo->rx_freeq, req);
                         devinfo->bus_pub.bus->dstats.rx_errors++;
                 } else {
                         brcmf_rx_packet(devinfo->dev, ifidx, skb);
@@ -557,6 +558,7 @@ static void brcmf_usb_rx_complete(struct urb *urb)
                 }
         } else {
                 brcmu_pkt_buf_free_skb(skb);
+                brcmf_usb_enq(devinfo, &devinfo->rx_freeq, req);
         }
         return;
 
@@ -582,11 +584,11 @@ static void brcmf_usb_rx_refill(struct brcmf_usbdev_info *devinfo,
                           skb->data, skb_tailroom(skb), brcmf_usb_rx_complete,
                           req);
         req->devinfo = devinfo;
+        brcmf_usb_enq(devinfo, &devinfo->rx_postq, req);
 
         ret = usb_submit_urb(req->urb, GFP_ATOMIC);
-        if (ret == 0) {
-                brcmf_usb_enq(devinfo, &devinfo->rx_postq, req);
-        } else {
+        if (ret) {
+                brcmf_usb_del_fromq(devinfo, req);
                 brcmu_pkt_buf_free_skb(req->skb);
                 req->skb = NULL;
                 brcmf_usb_enq(devinfo, &devinfo->rx_freeq, req);
@@ -682,23 +684,22 @@ static int brcmf_usb_tx(struct device *dev, struct sk_buff *skb)
 
         req = brcmf_usb_deq(devinfo, &devinfo->tx_freeq);
         if (!req) {
+                brcmu_pkt_buf_free_skb(skb);
                 brcmf_dbg(ERROR, "no req to send\n");
                 return -ENOMEM;
         }
-        if (!req->urb) {
-                brcmf_dbg(ERROR, "no urb for req %p\n", req);
-                return -ENOBUFS;
-        }
 
         req->skb = skb;
         req->devinfo = devinfo;
         usb_fill_bulk_urb(req->urb, devinfo->usbdev, devinfo->tx_pipe,
                           skb->data, skb->len, brcmf_usb_tx_complete, req);
         req->urb->transfer_flags |= URB_ZERO_PACKET;
+        brcmf_usb_enq(devinfo, &devinfo->tx_postq, req);
         ret = usb_submit_urb(req->urb, GFP_ATOMIC);
-        if (!ret) {
-                brcmf_usb_enq(devinfo, &devinfo->tx_postq, req);
-        } else {
+        if (ret) {
+                brcmf_dbg(ERROR, "brcmf_usb_tx usb_submit_urb FAILED\n");
+                brcmf_usb_del_fromq(devinfo, req);
+                brcmu_pkt_buf_free_skb(req->skb);
                 req->skb = NULL;
                 brcmf_usb_enq(devinfo, &devinfo->tx_freeq, req);
         }