diff mbox series

hw/net: npcm7xx_emc fix missing queue_flush

Message ID 20211203212714.1714362-1-venture@google.com (mailing list archive)
State New, archived
Headers show
Series hw/net: npcm7xx_emc fix missing queue_flush | expand

Commit Message

Patrick Venture Dec. 3, 2021, 9:27 p.m. UTC
The rx_active boolean change to true should always trigger a try_read
call that flushes the queue.

Signed-off-by: Patrick Venture <venture@google.com>
---
 hw/net/npcm7xx_emc.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

Comments

Philippe Mathieu-Daudé Dec. 3, 2021, 9:42 p.m. UTC | #1
On 12/3/21 22:27, Patrick Venture wrote:
> The rx_active boolean change to true should always trigger a try_read
> call that flushes the queue.
> 
> Signed-off-by: Patrick Venture <venture@google.com>
> ---
>  hw/net/npcm7xx_emc.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/net/npcm7xx_emc.c b/hw/net/npcm7xx_emc.c
> index 7c892f820f..97522e6388 100644
> --- a/hw/net/npcm7xx_emc.c
> +++ b/hw/net/npcm7xx_emc.c
> @@ -581,13 +581,6 @@ static ssize_t emc_receive(NetClientState *nc, const uint8_t *buf, size_t len1)
>      return len;
>  }
>  
> -static void emc_try_receive_next_packet(NPCM7xxEMCState *emc)
> -{
> -    if (emc_can_receive(qemu_get_queue(emc->nic))) {
> -        qemu_flush_queued_packets(qemu_get_queue(emc->nic));
> -    }
> -}

What about modifying as emc_flush_rx() or emc_receive_and_flush()
helper instead?

 static void emc_flush_rx(NPCM7xxEMCState *emc)
 {
     emc->rx_active = true;
     qemu_flush_queued_packets(qemu_get_queue(emc->nic));
 }

>  static uint64_t npcm7xx_emc_read(void *opaque, hwaddr offset, unsigned size)
>  {
>      NPCM7xxEMCState *emc = opaque;
> @@ -704,6 +697,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr offset,
>          }
>          if (value & REG_MCMDR_RXON) {
>              emc->rx_active = true;
> +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>          } else {
>              emc_halt_rx(emc, 0);
>          }
> @@ -740,7 +734,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr offset,
>      case REG_RSDR:
>          if (emc->regs[REG_MCMDR] & REG_MCMDR_RXON) {
>              emc->rx_active = true;
> -            emc_try_receive_next_packet(emc);
> +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>          }
>          break;
>      case REG_MIIDA:
>
Patrick Venture Dec. 3, 2021, 9:54 p.m. UTC | #2
On Fri, Dec 3, 2021 at 1:42 PM Philippe Mathieu-Daudé <f4bug@amsat.org>
wrote:

> On 12/3/21 22:27, Patrick Venture wrote:
> > The rx_active boolean change to true should always trigger a try_read
> > call that flushes the queue.
> >
> > Signed-off-by: Patrick Venture <venture@google.com>
> > ---
> >  hw/net/npcm7xx_emc.c | 10 ++--------
> >  1 file changed, 2 insertions(+), 8 deletions(-)
> >
> > diff --git a/hw/net/npcm7xx_emc.c b/hw/net/npcm7xx_emc.c
> > index 7c892f820f..97522e6388 100644
> > --- a/hw/net/npcm7xx_emc.c
> > +++ b/hw/net/npcm7xx_emc.c
> > @@ -581,13 +581,6 @@ static ssize_t emc_receive(NetClientState *nc,
> const uint8_t *buf, size_t len1)
> >      return len;
> >  }
> >
> > -static void emc_try_receive_next_packet(NPCM7xxEMCState *emc)
> > -{
> > -    if (emc_can_receive(qemu_get_queue(emc->nic))) {
> > -        qemu_flush_queued_packets(qemu_get_queue(emc->nic));
> > -    }
> > -}
>
> What about modifying as emc_flush_rx() or emc_receive_and_flush()
> helper instead?
>
>  static void emc_flush_rx(NPCM7xxEMCState *emc)
>  {
>      emc->rx_active = true;
>      qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>  }
>

I'm ok with that idea, although I'm less fond that it _hides_ the
rx_active=true.  There is an emc_halt_rx that hides rx_active=false, so one
could argue it's not an issue. Looking at ftgmac100, it mostly just calls
the qemu_flush_queued_packets inline where it needs it.  So given the prior
art, I'm more inclined to leave this as a two-line pair, versus collapsing
it into a method.  Mostly because I don't anticipate this call being made
from any other places, so it's not a "growing" device.  The method
originally was emc_try_receive_next_packet, which didn't do anything more
than a no-op check and the queue_flush.  The new method would move the
rx_active setting from the call that deliberately controls it (the register
change) into a subordinate method...

Beyond all that, I think it's fine either way.  Feel free to push back and
I'll make the change.

>
> >  static uint64_t npcm7xx_emc_read(void *opaque, hwaddr offset, unsigned
> size)
> >  {
> >      NPCM7xxEMCState *emc = opaque;
> > @@ -704,6 +697,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr
> offset,
> >          }
> >          if (value & REG_MCMDR_RXON) {
> >              emc->rx_active = true;
> > +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
> >          } else {
> >              emc_halt_rx(emc, 0);
> >          }
> > @@ -740,7 +734,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr
> offset,
> >      case REG_RSDR:
> >          if (emc->regs[REG_MCMDR] & REG_MCMDR_RXON) {
> >              emc->rx_active = true;
> > -            emc_try_receive_next_packet(emc);
> > +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
> >          }
> >          break;
> >      case REG_MIIDA:
> >
>
>
Patrick Venture Dec. 3, 2021, 10:10 p.m. UTC | #3
On Fri, Dec 3, 2021 at 1:54 PM Patrick Venture <venture@google.com> wrote:

>
>
> On Fri, Dec 3, 2021 at 1:42 PM Philippe Mathieu-Daudé <f4bug@amsat.org>
> wrote:
>
>> On 12/3/21 22:27, Patrick Venture wrote:
>> > The rx_active boolean change to true should always trigger a try_read
>> > call that flushes the queue.
>> >
>> > Signed-off-by: Patrick Venture <venture@google.com>
>> > ---
>> >  hw/net/npcm7xx_emc.c | 10 ++--------
>> >  1 file changed, 2 insertions(+), 8 deletions(-)
>> >
>> > diff --git a/hw/net/npcm7xx_emc.c b/hw/net/npcm7xx_emc.c
>> > index 7c892f820f..97522e6388 100644
>> > --- a/hw/net/npcm7xx_emc.c
>> > +++ b/hw/net/npcm7xx_emc.c
>> > @@ -581,13 +581,6 @@ static ssize_t emc_receive(NetClientState *nc,
>> const uint8_t *buf, size_t len1)
>> >      return len;
>> >  }
>> >
>> > -static void emc_try_receive_next_packet(NPCM7xxEMCState *emc)
>> > -{
>> > -    if (emc_can_receive(qemu_get_queue(emc->nic))) {
>> > -        qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>> > -    }
>> > -}
>>
>> What about modifying as emc_flush_rx() or emc_receive_and_flush()
>> helper instead?
>>
>>  static void emc_flush_rx(NPCM7xxEMCState *emc)
>>  {
>>      emc->rx_active = true;
>>      qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>>  }
>>
>
> I'm ok with that idea, although I'm less fond that it _hides_ the
> rx_active=true.  There is an emc_halt_rx that hides rx_active=false, so one
> could argue it's not an issue. Looking at ftgmac100, it mostly just calls
> the qemu_flush_queued_packets inline where it needs it.  So given the prior
> art, I'm more inclined to leave this as a two-line pair, versus collapsing
> it into a method.  Mostly because I don't anticipate this call being made
> from any other places, so it's not a "growing" device.  The method
> originally was emc_try_receive_next_packet, which didn't do anything more
> than a no-op check and the queue_flush.  The new method would move the
> rx_active setting from the call that deliberately controls it (the register
> change) into a subordinate method...
>
> Beyond all that, I think it's fine either way.  Feel free to push back and
> I'll make the change.
>

I figured why not :) And just made the change and sent out a v2.

>
>> >  static uint64_t npcm7xx_emc_read(void *opaque, hwaddr offset, unsigned
>> size)
>> >  {
>> >      NPCM7xxEMCState *emc = opaque;
>> > @@ -704,6 +697,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr
>> offset,
>> >          }
>> >          if (value & REG_MCMDR_RXON) {
>> >              emc->rx_active = true;
>> > +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>> >          } else {
>> >              emc_halt_rx(emc, 0);
>> >          }
>> > @@ -740,7 +734,7 @@ static void npcm7xx_emc_write(void *opaque, hwaddr
>> offset,
>> >      case REG_RSDR:
>> >          if (emc->regs[REG_MCMDR] & REG_MCMDR_RXON) {
>> >              emc->rx_active = true;
>> > -            emc_try_receive_next_packet(emc);
>> > +            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
>> >          }
>> >          break;
>> >      case REG_MIIDA:
>> >
>>
>>
diff mbox series

Patch

diff --git a/hw/net/npcm7xx_emc.c b/hw/net/npcm7xx_emc.c
index 7c892f820f..97522e6388 100644
--- a/hw/net/npcm7xx_emc.c
+++ b/hw/net/npcm7xx_emc.c
@@ -581,13 +581,6 @@  static ssize_t emc_receive(NetClientState *nc, const uint8_t *buf, size_t len1)
     return len;
 }
 
-static void emc_try_receive_next_packet(NPCM7xxEMCState *emc)
-{
-    if (emc_can_receive(qemu_get_queue(emc->nic))) {
-        qemu_flush_queued_packets(qemu_get_queue(emc->nic));
-    }
-}
-
 static uint64_t npcm7xx_emc_read(void *opaque, hwaddr offset, unsigned size)
 {
     NPCM7xxEMCState *emc = opaque;
@@ -704,6 +697,7 @@  static void npcm7xx_emc_write(void *opaque, hwaddr offset,
         }
         if (value & REG_MCMDR_RXON) {
             emc->rx_active = true;
+            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
         } else {
             emc_halt_rx(emc, 0);
         }
@@ -740,7 +734,7 @@  static void npcm7xx_emc_write(void *opaque, hwaddr offset,
     case REG_RSDR:
         if (emc->regs[REG_MCMDR] & REG_MCMDR_RXON) {
             emc->rx_active = true;
-            emc_try_receive_next_packet(emc);
+            qemu_flush_queued_packets(qemu_get_queue(emc->nic));
         }
         break;
     case REG_MIIDA: