net: wwan: mhi_wwan_ctrl: Fix RX buffer starvation

The mhi_wwan_rx_budget_dec function is supposed to return true if
RX buffer budget has been successfully decremented, allowing to queue
a new RX buffer for transfer. However the current implementation is
broken when RX budget is '1', in which case budget is decremented but
false is returned, preventing to requeue one buffer, and leading to
RX buffer starvation.

Fixes: fa588eba632d ("net: Add Qcom WWAN control driver")
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wwan/mhi_wwan_ctrl.c b/drivers/net/wwan/mhi_wwan_ctrl.c
index 416ae6abafb768088b03d098de6a39a37a3e87f3..1bc6b69aa530269630ad3af3de026be1d149d775 100644 (file)
--- a/drivers/net/wwan/mhi_wwan_ctrl.c
+++ b/drivers/net/wwan/mhi_wwan_ctrl.c
@@ -58,11 +58,11 @@ static bool mhi_wwan_rx_budget_dec(struct mhi_wwan_dev *mhiwwan)
 
        spin_lock(&mhiwwan->rx_lock);
 
-       if (mhiwwan->rx_budget)
+       if (mhiwwan->rx_budget) {
                mhiwwan->rx_budget--;
-
-       if (mhiwwan->rx_budget && test_bit(MHI_WWAN_RX_REFILL, &mhiwwan->flags))
-               ret = true;
+               if (test_bit(MHI_WWAN_RX_REFILL, &mhiwwan->flags))
+                       ret = true;
+       }
 
        spin_unlock(&mhiwwan->rx_lock);