amd-xgbe: schedule NAPI on Rx Buffer Unavailable (RBU)

Under heavy load, Rx Buffer Unavailable (RBU) can occur if Rx processing
is slower than network. When an RBU is signaled, try to schedule NAPI to
help recover from such situation (including cases where an IRQ may be
missed or such)

Signed-off-by: Raju Rangoju <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: RajuRangoju

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

@@ -410,15 +410,29 @@ static void xgbe_isr_bh_work(struct work_struct *work)
 		 * Decide which NAPI to use and whether to schedule:
 		 * - When not using per-channel IRQs: schedule on global NAPI
 		 *   if TI or RI are set.
+		 * - RBU should also trigger NAPI (either per-channel or global)
+		 *   to allow refill.
 		 */
 		if (!per_ch_irq && (ti || ri))
 			schedule_napi = true;
 
+		if (rbu) {
+			schedule_napi = true;
+			pdata->ext_stats.rx_buffer_unavailable++;
+		}
+
 		napi = per_ch_irq ? &channel->napi : &pdata->napi;
 
 		if (schedule_napi && napi_schedule_prep(napi)) {
 			/* Disable interrupts appropriately before polling */
-			xgbe_disable_rx_tx_ints(pdata);
+			if (per_ch_irq) {
+				if (pdata->channel_irq_mode)
+					xgbe_disable_rx_tx_int(pdata, channel);
+				else
+					disable_irq_nosync(channel->dma_irq);
+			} else {
+				xgbe_disable_rx_tx_ints(pdata);
+			}
 
 			/* Turn on polling */
 			__napi_schedule(napi);
@@ -436,9 +450,6 @@ static void xgbe_isr_bh_work(struct work_struct *work)
 			XGMAC_SET_BITS(dma_ch_isr, DMA_CH_SR, RI, 0);
 		}
 
-		if (rbu)
-			pdata->ext_stats.rx_buffer_unavailable++;
-
 		/* Restart the device on a Fatal Bus Error */
 		if (fbe)
 			schedule_work(&pdata->restart_work);