From: Ilias Apalodimas Date: Thu, 11 Oct 2018 12:28:26 +0000 (+0300) Subject: net: socionext: clear rx irq correctly X-Git-Tag: v4.19~56^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2a1e89df785082a0fd7264ca6d3d834abe84fa25;p=platform%2Fkernel%2Flinux-rpi.git net: socionext: clear rx irq correctly 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 Reported-by: Ard Biesheuvel Tested-by: Ard Biesheuvel Acked-by: Ard Biesheuvel Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c index 7aa5ebb6766c..4289ccb26e4e 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