Patch "ethtool: fix ethtool msg len calculation for pause stats" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ethtool: fix ethtool msg len calculation for pause stats

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ethtool-fix-ethtool-msg-len-calculation-for-pause-st.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bc4ac19db34c089b4dcdb9b93288b83cf84a2fd0
Author: Jakub Kicinski <kuba@xxxxxxxxxx>
Date:   Tue Nov 2 15:02:36 2021 -0700

    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@xxxxxxxxxx>
    Reviewed-by: Saeed Mahameed <saeedm@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/linux/ethtool_netlink.h b/include/linux/ethtool_netlink.h
index 1e7bf78cb3829..aba348d58ff61 100644
--- 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 e2bf36e6964b6..c94fa29415021 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -394,7 +394,9 @@ 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 d4ac02718b72a..c7bc704c8862a 100644
--- a/net/ethtool/pause.c
+++ b/net/ethtool/pause.c
@@ -62,8 +62,7 @@ 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;
 }