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Re: [Qemu-devel] [PATCH v2 for-2.4 12/12] axienet: Flush queued packets
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v2 for-2.4 12/12] axienet: Flush queued packets when rx is done |
Date: |
Thu, 16 Jul 2015 11:32:47 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Thu, 07/16 10:58, Jason Wang wrote:
>
>
> On 07/15/2015 06:19 PM, Fam Zheng wrote:
> > eth_can_rx checks s->rxsize and returns false if it is non-zero. Because
> > of the .can_receive semantics change, this will make the incoming queue
> > disabled by peer, until it is explicitly flushed. So we should flush it
> > when s->rxsize is becoming zero.
> >
> > Squash eth_can_rx semantics into etx_rx and drop .can_receive()
> > callback, also add flush when rx buffer becomes available again after a
> > packet gets queued.
> >
> > The other conditions, "!axienet_rx_resetting(s) &&
> > axienet_rx_enabled(s)" are OK because enet_write already calls
> > qemu_flush_queued_packets when the register bits are changed.
> >
> > Signed-off-by: Fam Zheng <address@hidden>
> > ---
> > hw/net/xilinx_axienet.c | 17 +++++++++++++----
> > 1 file changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
> > index 9205770..d63c423 100644
> > --- a/hw/net/xilinx_axienet.c
> > +++ b/hw/net/xilinx_axienet.c
> > @@ -401,6 +401,9 @@ struct XilinxAXIEnet {
> >
> > uint8_t rxapp[CONTROL_PAYLOAD_SIZE];
> > uint32_t rxappsize;
> > +
> > + /* Whether axienet_eth_rx_notify should flush incoming queue. */
> > + bool need_flush;
> > };
> >
> > static void axienet_rx_reset(XilinxAXIEnet *s)
> > @@ -658,10 +661,8 @@ static const MemoryRegionOps enet_ops = {
> > .endianness = DEVICE_LITTLE_ENDIAN,
> > };
> >
> > -static int eth_can_rx(NetClientState *nc)
> > +static int eth_can_rx(XilinxAXIEnet *s)
> > {
> > - XilinxAXIEnet *s = qemu_get_nic_opaque(nc);
> > -
> > /* RX enabled? */
> > return !s->rxsize && !axienet_rx_resetting(s) && axienet_rx_enabled(s);
> > }
> > @@ -701,6 +702,10 @@ static void axienet_eth_rx_notify(void *opaque)
> > s->rxpos += ret;
> > if (!s->rxsize) {
> > s->regs[R_IS] |= IS_RX_COMPLETE;
> > + if (s->need_flush) {
> > + s->need_flush = false;
> > + qemu_flush_queued_packets(qemu_get_queue(s->nic));
> > + }
> > }
> > }
> > enet_update_irq(s);
> > @@ -721,6 +726,11 @@ static ssize_t eth_rx(NetClientState *nc, const
> > uint8_t *buf, size_t size)
> >
> > DENET(qemu_log("%s: %zd bytes\n", __func__, size));
> >
> > + if (!eth_can_rx(s)) {
> > + s->need_flush = true;
> > + return 0;
> > + }
> > +
>
> axienet_eth_rx_notify() was only called by eth_rx(). So when
> s->need_flush is true, we won't ever reach axienet_eth_rx_notify()?
We will.
If we are here it measn a previous call to axienet_eth_rx_notify hasn't drained
the buffer:
static void axienet_eth_rx_notify(void *opaque)
{
...
while (s->rxsize && stream_can_push(s->tx_data_dev,
axienet_eth_rx_notify, s)) {
size_t ret = stream_push(s->tx_data_dev, (void *)s->rxmem +
s->rxpos,
s->rxsize);
s->rxsize -= ret;
s->rxpos += ret;
if (!s->rxsize) {
s->regs[R_IS] |= IS_RX_COMPLETE;
}
}
...
}
axienet_eth_rx_notify is passed to stream_can_push so it will be reached again
once s->tx_data_dev can receive more data:
typedef struct StreamSlaveClass {
InterfaceClass parent;
/**
* can push - determine if a stream slave is capable of accepting at
least
* one byte of data. Returns false if cannot accept. If not
implemented, the
* slave is assumed to always be capable of receiving.
* @notify: Optional callback that the slave will call when the slave is
* capable of receiving again. Only called if false is returned.
* @notify_opaque: opaque data to pass to notify call.
*/
bool (*can_push)(StreamSlave *obj, StreamCanPushNotifyFn notify,
void *notify_opaque);
...
Am I missing anything?
Fam
- [Qemu-devel] [PATCH v2 for-2.4 04/12] usbnet: Drop usbnet_can_receive, (continued)
- [Qemu-devel] [PATCH v2 for-2.4 04/12] usbnet: Drop usbnet_can_receive, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 05/12] etsec: Move etsec_can_receive into etsec_receive, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 06/12] etsec: Flush queue when rx buffer is consumed, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 07/12] mcf_fec: Drop mcf_fec_can_receive, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 09/12] mipsnet: Flush queued packets when receiving is enabled, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 08/12] milkymist-minimac2: Flush queued packets when link comes up, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 10/12] stellaris_enet: Flush queued packets when read done, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 11/12] dp8393x: Flush packets when link comes up, Fam Zheng, 2015/07/15
- [Qemu-devel] [PATCH v2 for-2.4 12/12] axienet: Flush queued packets when rx is done, Fam Zheng, 2015/07/15
- Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for NICs, Jason Wang, 2015/07/16
- Re: [Qemu-devel] [PATCH v2 for-2.4 00/12] hw/net: Fix .can_receive() for NICs, Stefan Hajnoczi, 2015/07/20