| Message ID | 1539260906-29596-1-git-send-email-ilias.apalodimas@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] net: socionext: clear rx irq correctly | expand |
On 11 October 2018 at 14:28, Ilias Apalodimas <ilias.apalodimas@linaro.org> wrote: > 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 <ilias.apalodimas@linaro.org> > Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > 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 >
From: Ilias Apalodimas <ilias.apalodimas@linaro.org> Date: Thu, 11 Oct 2018 15:28:26 +0300 > 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 <ilias.apalodimas@linaro.org> > Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Applied.
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
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 <ilias.apalodimas@linaro.org> Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- drivers/net/ethernet/socionext/netsec.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- 2.7.4