Re: [PATCH net] ethtool: fix ethtool msg len calculation for pause stats

On Tue, 2 Nov 2021 16:08:52 +0000 Saeed Mahameed wrote:

quoted

diff --git a/net/ethtool/pause.c b/net/ethtool/pause.c
index 9009f412151e..c9171234130b 100644
--- a/net/ethtool/pause.c
+++ b/net/ethtool/pause.c

@@ -57,7 +57,7 @@ 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);
+                               (ETHTOOL_A_PAUSE_STAT_MAX - 1);  

Maybe for net-next we can improve readability here.
Just by staring at these lines, you'd think that this should've been
(ETHTOOL_A_PAUSE_STAT_MAX + 1), or even better, just
(ETHTOOL_A_PAUSE_STAT_CNT) /* Count of only stats */

maybe we need to separate stats from non-stats, or define
ETHTOOL_A_PAUSE_STAT_CNT where it needs to be defined.

Fair point, something like this?

+++ b/include/uapi/linux/ethtool_netlink.h

@@ -411,10 +411,14 @@ 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)
 };
+#define ETHTOOL_PAUSE_STAT_CNT (__ETHTOOL_A_PAUSE_STAT_CNT -           \
+                                ETHTOOL_A_PAUSE_STAT_TX_FRAMES)
 
 /* EEE */