ionic: minimal work with 0 budget

We should be doing as little as possible besides freeing Tx
space when our napi routines are called with budget of 0, so
jump out before doing anything besides Tx cleaning.

See commit afbed3f74830 ("net/mlx5e: do as little as possible in napi poll when budget is 0")
for more info.

Fixes: fe8c30b50835 ("ionic: separate interrupt for Tx and Rx")
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240210001307.48450-1-shannon.nelson@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
index 54cd96b..6f47767 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
@@ -579,6 +579,9 @@ int ionic_tx_napi(struct napi_struct *napi, int budget)
        work_done = ionic_cq_service(cq, budget,
                                     ionic_tx_service, NULL, NULL);
 
+       if (unlikely(!budget))
+               return budget;
+
        if (work_done < budget && napi_complete_done(napi, work_done)) {
                ionic_dim_update(qcq, IONIC_LIF_F_TX_DIM_INTR);
                flags |= IONIC_INTR_CRED_UNMASK;
@@ -607,6 +610,9 @@ int ionic_rx_napi(struct napi_struct *napi, int budget)
        u32 work_done = 0;
        u32 flags = 0;
 
+       if (unlikely(!budget))
+               return budget;
+
        lif = cq->bound_q->lif;
        idev = &lif->ionic->idev;
 
@@ -656,6 +662,9 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
        tx_work_done = ionic_cq_service(txcq, IONIC_TX_BUDGET_DEFAULT,
                                        ionic_tx_service, NULL, NULL);
 
+       if (unlikely(!budget))
+               return budget;
+
        rx_work_done = ionic_cq_service(rxcq, budget,
                                        ionic_rx_service, NULL, NULL);