Patch "ethtool: rss: fix hiding unsupported fields in dumps" has been added to the 6.12-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    ethtool: rss: fix hiding unsupported fields in dumps

to the 6.12-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-rss-fix-hiding-unsupported-fields-in-dumps.patch
and it can be found in the queue-6.12 subdirectory.

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



commit 83cb8c5c6fff22d00a7c7ec51ad0092a6dd4301e
Author: Jakub Kicinski <kuba@xxxxxxxxxx>
Date:   Fri Jan 31 17:30:37 2025 -0800

    ethtool: rss: fix hiding unsupported fields in dumps
    
    [ Upstream commit 244f8aa46fa9e2f4ea5fe0e04988b395d5e30fc7 ]
    
    Commit ec6e57beaf8b ("ethtool: rss: don't report key if device
    doesn't support it") intended to stop reporting key fields for
    additional rss contexts if device has a global hashing key.
    
    Later we added dump support and the filtering wasn't properly
    added there. So we end up reporting the key fields in dumps
    but not in dos:
    
      # ./pyynl/cli.py --spec netlink/specs/ethtool.yaml --do rss-get \
                    --json '{"header": {"dev-index":2}, "context": 1 }'
      {
         "header": { ... },
         "context": 1,
         "indir": [0, 1, 2, 3, ...]]
      }
    
      # ./pyynl/cli.py --spec netlink/specs/ethtool.yaml --dump rss-get
      [
         ... snip context 0 ...
         { "header": { ... },
           "context": 1,
           "indir": [0, 1, 2, 3, ...],
     ->    "input_xfrm": 255,
     ->    "hfunc": 1,
     ->    "hkey": "000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"
         }
      ]
    
    Hide these fields correctly.
    
    The drivers/net/hw/rss_ctx.py selftest catches this when run on
    a device with single key, already:
    
      # Check| At /root/./ksft-net-drv/drivers/net/hw/rss_ctx.py, line 381, in test_rss_context_dump:
      # Check|     ksft_ne(set(data.get('hkey', [1])), {0}, "key is all zero")
      # Check failed {0} == {0} key is all zero
      not ok 8 rss_ctx.test_rss_context_dump
    
    Fixes: f6122900f4e2 ("ethtool: rss: support dumping RSS contexts")
    Reviewed-by: Gal Pressman <gal@xxxxxxxxxx>
    Reviewed-by: Joe Damato <jdamato@xxxxxxxxxx>
    Link: https://patch.msgid.link/20250201013040.725123-2-kuba@xxxxxxxxxx
    Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c
index e07386275e142..8aa45f3fdfdf0 100644
--- a/net/ethtool/rss.c
+++ b/net/ethtool/rss.c
@@ -107,6 +107,8 @@ rss_prepare_ctx(const struct rss_req_info *request, struct net_device *dev,
 	u32 total_size, indir_bytes;
 	u8 *rss_config;
 
+	data->no_key_fields = !dev->ethtool_ops->rxfh_per_ctx_key;
+
 	ctx = xa_load(&dev->ethtool->rss_ctx, request->rss_context);
 	if (!ctx)
 		return -ENOENT;
@@ -153,7 +155,6 @@ rss_prepare_data(const struct ethnl_req_info *req_base,
 		if (!ops->cap_rss_ctx_supported && !ops->create_rxfh_context)
 			return -EOPNOTSUPP;
 
-		data->no_key_fields = !ops->rxfh_per_ctx_key;
 		return rss_prepare_ctx(request, dev, data, info);
 	}