commit 63ae7949e94a ("net: socionext: Use descriptor info instead of MMIO reads
on Rx")
removed constant mmio reads from the driver and started using a descriptor
field to check if packet should be processed.
This lead the napi rx handler being constantly called while no packets
needed processing and ksoftirq getting 100% cpu usage. Issue one mmio read
to clear the irq correcty after processing packets
Signed-off-by: Ilias Apalodimas <[email protected]>
Reported-by: Ard Biesheuvel <[email protected]>
---
drivers/net/ethernet/socionext/netsec.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/socionext/netsec.c
b/drivers/net/ethernet/socionext/netsec.c
index 7aa5ebb..4289ccb 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -735,8 +735,11 @@ static int netsec_process_rx(struct netsec_priv *priv, int
budget)
u16 idx = dring->tail;
struct netsec_de *de = dring->vaddr + (DESC_SZ * idx);
- if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD))
+ if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD)) {
+ /* reading the register clears the irq */
+ netsec_read(priv, NETSEC_REG_NRM_RX_PKTCNT);
break;
+ }
/* This barrier is needed to keep us from reading
* any other fields out of the netsec_de until we have
--
2.7.4
