diff options
| author | Jerome Forissier <jerome.forissier@linaro.org> | 2024-10-09 11:42:08 +0200 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2024-10-27 17:03:40 -0600 |
| commit | 63150710e34aa9d5d7c45e142e70016b31af2c04 (patch) | |
| tree | 8f145bb5142cd9c3f04627e986dc1fdd9f7a7750 | |
| parent | 8963d433eb5d4a9f3a9def84e9c61a45c13e72bc (diff) | |
net: recv(): return -EAGAIN instead of 0 when no cleanup is expected
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 -EAGAIN instead of 0 when no packet is
available and the driver doesn't expect free_pkt() to be called
subsequently.
[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.forissier@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
| -rw-r--r-- | drivers/net/eepro100.c | 2 | ||||
| -rw-r--r-- | drivers/net/rtl8139.c | 2 |
2 files changed, 2 insertions, 2 deletions
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. */ |