ethtool: fix ethtool msg len calculation for pause stats

[ Upstream commit 1aabe578dd86e9f2867c4db4fba9a15f4ba1825d ]

ETHTOOL_A_PAUSE_STAT_MAX is the MAX attribute id,
so we need to subtract non-stats and add one to
get a count (IOW -2+1 == -1).

Otherwise we'll see:

  ethnl cmd 21: calculated reply length 40, but consumed 52

Fixes: 9a27a33027f2 ("ethtool: add standard pause stats")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/ethtool_netlink.h b/include/linux/ethtool_netlink.h
index 1e7bf78..aba348d 100644 (file)
--- a/include/linux/ethtool_netlink.h
+++ b/include/linux/ethtool_netlink.h
@@ -10,6 +10,9 @@
 #define __ETHTOOL_LINK_MODE_MASK_NWORDS \
        DIV_ROUND_UP(__ETHTOOL_LINK_MODE_MASK_NBITS, 32)
 
+#define ETHTOOL_PAUSE_STAT_CNT (__ETHTOOL_A_PAUSE_STAT_CNT -           \
+                                ETHTOOL_A_PAUSE_STAT_TX_FRAMES)
+
 enum ethtool_multicast_groups {
        ETHNL_MCGRP_MONITOR,
 };

diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 5545f1c..f7204bd 100644 (file)
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -407,7 +407,9 @@ enum {
        ETHTOOL_A_PAUSE_STAT_TX_FRAMES,
        ETHTOOL_A_PAUSE_STAT_RX_FRAMES,
 
-       /* add new constants above here */
+       /* add new constants above here
+        * adjust ETHTOOL_PAUSE_STAT_CNT if adding non-stats!
+        */
        __ETHTOOL_A_PAUSE_STAT_CNT,
        ETHTOOL_A_PAUSE_STAT_MAX = (__ETHTOOL_A_PAUSE_STAT_CNT - 1)
 };

diff --git a/net/ethtool/pause.c b/net/ethtool/pause.c
index 9009f41..ee1e580 100644 (file)
--- a/net/ethtool/pause.c
+++ b/net/ethtool/pause.c
@@ -56,8 +56,7 @@ static int pause_reply_size(const struct ethnl_req_info *req_base,
 
        if (req_base->flags & ETHTOOL_FLAG_STATS)
                n += nla_total_size(0) +        /* _PAUSE_STATS */
-                       nla_total_size_64bit(sizeof(u64)) *
-                               (ETHTOOL_A_PAUSE_STAT_MAX - 2);
+                    nla_total_size_64bit(sizeof(u64)) * ETHTOOL_PAUSE_STAT_CNT;
        return n;
 }