On Thu, 3 Oct 2024 at 09:23, Jerome Forissier <jerome.foriss...@linaro.org> wrote: > > Note: patch posted separately [0]. > > [0] > http://patchwork.ozlabs.org/project/uboot/patch/20240927142038.879037-1-jerome.foriss...@linaro.org/ > > Some drivers do not behave properly when free_pkt() is called with a > length of zero. It is an issue I observed when developing the lwIP > series [1] (see "QEMU CI tests for r2dplus_i82557c, r2dplus_rtl8139" > in the change log) and which I fixed incorrectly by not calling > free_pkt() when recv() returns 0. That turned out to be wrong for two > reasons: > > 1. The DM documentation [2] clearly requires it: > > "The **recv** function polls for availability of a new packet. [...] > If there is an error [...], return 0 if you require the packet to > be cleaned up normally, or a negative error code otherwise (cleanup > not necessary or already done). > > If **free_pkt** is defined, U-Boot will call it after a received > packet has been processed [...]. free_pkt() will be called after > recv(), for the same packet [...]" > > 2. The imx8mp_evk platform will fail with OOM errors if free_pkt() is > not called after recv() returns 0: > > u-boot=> tftp 192.168.0.16:50M > Using ethernet@30be0000 device > TFTP from server 192.168.0.16; our IP address is 192.168.0.48 > Filename '50M'. > Load address: 0x40480000 > Loading: #######################fecmxc_recv: error allocating packetp > fecmxc_recv: error allocating packetp > fecmxc_recv: error allocating packetp > ... > > Therefore, make recv() return -EINVAL instead of 0 when no packet is > available and the driver doesn't expect free_pkt() to be called > subsequently.
Do you mean -EAGAIN ? Otherwise, it seems like this comment relates to a different patch. > > [1] https://lists.denx.de/pipermail/u-boot/2024-August/562861.html > [2] doc/develop/driver-model/ethernet.rst > > Signed-off-by: Jerome Forissier <jerome.foriss...@linaro.org> > --- > drivers/net/eepro100.c | 2 +- > drivers/net/rtl8139.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > Reviewed-by: Simon Glass <s...@chromium.org> > diff --git a/drivers/net/eepro100.c b/drivers/net/eepro100.c > index d18a8d577ca..f64dbb7d6a1 100644 > --- a/drivers/net/eepro100.c > +++ b/drivers/net/eepro100.c > @@ -678,7 +678,7 @@ static int eepro100_recv_common(struct eepro100_priv > *priv, uchar **packetp) > status = le16_to_cpu(desc->status); > > if (!(status & RFD_STATUS_C)) > - return 0; > + return -EAGAIN; > > /* Valid frame status. */ > if (status & RFD_STATUS_OK) { > diff --git a/drivers/net/rtl8139.c b/drivers/net/rtl8139.c > index 2e0afad089f..5f4b1e2d3a0 100644 > --- a/drivers/net/rtl8139.c > +++ b/drivers/net/rtl8139.c > @@ -433,7 +433,7 @@ static int rtl8139_recv_common(struct rtl8139_priv *priv, > unsigned char *rxdata, > int length = 0; > > if (inb(priv->ioaddr + RTL_REG_CHIPCMD) & RTL_REG_CHIPCMD_RXBUFEMPTY) > - return 0; > + return -EAGAIN; > > priv->rxstatus = inw(priv->ioaddr + RTL_REG_INTRSTATUS); > /* See below for the rest of the interrupt acknowledges. */ > -- > 2.40.1 >
