[PATCH] net: tftp: don't call stop callback from UDP handler

[A. Sverdlin]

From: Alexander Sverdlin <alexander.sverdlin at siemens.com>

Contrary to doc/develop/driver-model/ethernet.rst contract, eth_ops
.free_pkt can be called after .stop, there are several error paths in TFTP,
for instance:

eth_halt() <= tftp_handler() <= net_process_received_packet() <= eth_rx()
...
am65_cpsw_free_pkt() <= eth_rx()

Which results in (deliberately "tftpboot"ing non-existing file):

TFTP error: 'File not found' (1)
Not retrying...
am65_cpsw_nuss_port ethernet at 8000000port@1: RX dma free_pkt failed -22

Avoid the DMA error message (and follow the documentation) by deferring
eth_halt() until net_loop() calls net_start_again() and only do
eth_halt_state_only() instead.

Fixes: aafda38fb266 ("Add error codes/handling for TFTP-server")
Signed-off-by: Alexander Sverdlin <alexander.sverdlin at siemens.com>
---
 net/eth-uclass.c | 2 ++
 net/tftp.c       | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

This isn't a v2, but a completely different approach to
https://patchwork.ozlabs.org/project/uboot/patch/20240508183605.955341-1-alexander.sverdlin@siemens.com/

diff --git a/net/eth-uclass.c b/net/eth-uclass.c
index 193218a328b..9863db59d68 100644
--- a/net/eth-uclass.c
+++ b/net/eth-uclass.c
@@ -450,6 +450,8 @@ int eth_rx(void)
 			eth_get_ops(current)->free_pkt(current, packet, ret);
 		if (ret <= 0)
 			break;
+		if (!eth_is_active(current))
+			break;
 	}
 	if (ret == -EAGAIN)
 		ret = 0;
diff --git a/net/tftp.c b/net/tftp.c
index 2e335413492..081014a1fde 100644
--- a/net/tftp.c
+++ b/net/tftp.c
@@ -649,7 +649,7 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 		net_set_timeout_handler(timeout_ms, tftp_timeout_handler);
 
 		if (store_block(tftp_cur_block, pkt + 2, len)) {
-			eth_halt();
+			eth_halt_state_only();
 			net_set_state(NETLOOP_FAIL);
 			break;
 		}
@@ -678,7 +678,7 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 		case TFTP_ERR_FILE_NOT_FOUND:
 		case TFTP_ERR_ACCESS_DENIED:
 			puts("Not retrying...\n");
-			eth_halt();
+			eth_halt_state_only();
 			net_set_state(NETLOOP_FAIL);
 			break;
 		case TFTP_ERR_UNDEFINED:
-- 
2.44.0