alx: fix alx_poll()

Commit d75b1ade567f ("net: less interrupt masking in NAPI") uncovered
wrong alx_poll() behavior.

A NAPI poll() handler is supposed to return exactly the budget when/if
napi_complete() has not been called.

It is also supposed to return number of frames that were received, so
that netdev_budget can have a meaning.

Also, in case of TX pressure, we still have to dequeue received
packets : alx_clean_rx_irq() has to be called even if
alx_clean_tx_irq(alx) returns false, otherwise device is half duplex.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: d75b1ade567f ("net: less interrupt masking in NAPI")
Reported-by: Oded Gabbay <oded.gabbay@amd.com>
Bisected-by: Oded Gabbay <oded.gabbay@amd.com>
Tested-by: Oded Gabbay <oded.gabbay@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/atheros/alx/main.c b/drivers/net/ethernet/atheros/alx/main.c
index e398eda..c8af3ce 100644 (file)
--- a/drivers/net/ethernet/atheros/alx/main.c
+++ b/drivers/net/ethernet/atheros/alx/main.c
@@ -184,15 +184,16 @@ static void alx_schedule_reset(struct alx_priv *alx)
        schedule_work(&alx->reset_wk);
 }
 
-static bool alx_clean_rx_irq(struct alx_priv *alx, int budget)
+static int alx_clean_rx_irq(struct alx_priv *alx, int budget)
 {
        struct alx_rx_queue *rxq = &alx->rxq;
        struct alx_rrd *rrd;
        struct alx_buffer *rxb;
        struct sk_buff *skb;
        u16 length, rfd_cleaned = 0;
+       int work = 0;
 
-       while (budget > 0) {
+       while (work < budget) {
                rrd = &rxq->rrd[rxq->rrd_read_idx];
                if (!(rrd->word3 & cpu_to_le32(1 << RRD_UPDATED_SHIFT)))
                        break;
@@ -203,7 +204,7 @@ static bool alx_clean_rx_irq(struct alx_priv *alx, int budget)
                    ALX_GET_FIELD(le32_to_cpu(rrd->word0),
                                  RRD_NOR) != 1) {
                        alx_schedule_reset(alx);
-                       return 0;
+                       return work;
                }
 
                rxb = &rxq->bufs[rxq->read_idx];
@@ -243,7 +244,7 @@ static bool alx_clean_rx_irq(struct alx_priv *alx, int budget)
                }
 
                napi_gro_receive(&alx->napi, skb);
-               budget--;
+               work++;
 
 next_pkt:
                if (++rxq->read_idx == alx->rx_ringsz)
@@ -258,21 +259,22 @@ next_pkt:
        if (rfd_cleaned)
                alx_refill_rx_ring(alx, GFP_ATOMIC);
 
-       return budget > 0;
+       return work;
 }
 
 static int alx_poll(struct napi_struct *napi, int budget)
 {
        struct alx_priv *alx = container_of(napi, struct alx_priv, napi);
        struct alx_hw *hw = &alx->hw;
-       bool complete = true;
        unsigned long flags;
+       bool tx_complete;
+       int work;
 
-       complete = alx_clean_tx_irq(alx) &&
-                  alx_clean_rx_irq(alx, budget);
+       tx_complete = alx_clean_tx_irq(alx);
+       work = alx_clean_rx_irq(alx, budget);
 
-       if (!complete)
-               return 1;
+       if (!tx_complete || work == budget)
+               return budget;
 
        napi_complete(&alx->napi);
 
@@ -284,7 +286,7 @@ static int alx_poll(struct napi_struct *napi, int budget)
 
        alx_post_write(hw);
 
-       return 0;
+       return work;
 }
 
 static irqreturn_t alx_intr_handle(struct alx_priv *alx, u32 intr)