[PATCH net 1/5] netdev: fix repeated netlink messages in queue dump

[Jakub Kicinski <kuba@kernel.org>]

The context is supposed to record the next queue do dump,
not last dumped. If the dump doesn't fit we will restart
from the already-dumped queue, duplicating the message.

Before this fix and with the selftest improvements later
in this series we see:

  # ./run_kselftest.sh -t drivers/net:queues.py
  timeout set to 45
  selftests: drivers/net: queues.py
  KTAP version 1
  1..2
  # Check| At /root/ksft-net-drv/drivers/net/./queues.py, line 32, in get_queues:
  # Check|     ksft_eq(queues, expected)
  # Check failed 102 != 100
  # Check| At /root/ksft-net-drv/drivers/net/./queues.py, line 32, in get_queues:
  # Check|     ksft_eq(queues, expected)
  # Check failed 101 != 100
  not ok 1 queues.get_queues
  ok 2 queues.addremove_queues
  # Totals: pass:1 fail:1 xfail:0 xpass:0 skip:0 error:0
  not ok 1 selftests: drivers/net: queues.py # exit=1

With the fix:

  # ./ksft-net-drv/run_kselftest.sh -t drivers/net:queues.py
  timeout set to 45
  selftests: drivers/net: queues.py
  KTAP version 1
  1..2
  ok 1 queues.get_queues
  ok 2 queues.addremove_queues
  # Totals: pass:2 fail:0 xfail:0 xpass:0 skip:0 error:0

Fixes: 6b6171db7fc8 ("netdev-genl: Add netlink framework functions for queue")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: jdamato@fastly.com
CC: almasrymina@google.com
CC: amritha.nambiar@intel.com
CC: sridhar.samudrala@intel.com
---
 net/core/netdev-genl.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 9527dd46e4dc..9f086b190619 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -488,24 +488,21 @@ netdev_nl_queue_dump_one(struct net_device *netdev, struct sk_buff *rsp,
 			 struct netdev_nl_dump_ctx *ctx)
 {
 	int err = 0;
-	int i;
 
 	if (!(netdev->flags & IFF_UP))
 		return err;
 
-	for (i = ctx->rxq_idx; i < netdev->real_num_rx_queues;) {
-		err = netdev_nl_queue_fill_one(rsp, netdev, i,
+	for (; ctx->rxq_idx < netdev->real_num_rx_queues; ctx->rxq_idx++) {
+		err = netdev_nl_queue_fill_one(rsp, netdev, ctx->rxq_idx,
 					       NETDEV_QUEUE_TYPE_RX, info);
 		if (err)
 			return err;
-		ctx->rxq_idx = i++;
 	}
-	for (i = ctx->txq_idx; i < netdev->real_num_tx_queues;) {
-		err = netdev_nl_queue_fill_one(rsp, netdev, i,
+	for (; ctx->txq_idx < netdev->real_num_tx_queues; ctx->txq_idx++) {
+		err = netdev_nl_queue_fill_one(rsp, netdev, ctx->txq_idx,
 					       NETDEV_QUEUE_TYPE_TX, info);
 		if (err)
 			return err;
-		ctx->txq_idx = i++;
 	}
 
 	return err;
-- 
2.47.1