kernel/linux.git/net/ethtool/rss.c, branch v6.18.35

ethtool: rss: avoid device context leak on reply-build failure

2026-06-09T10:28:27+00:00

[ Upstream commit 32a9ecde62731c9f7412507709192c84dafc38d1 ] We wait with filling the reply for new RSS context creation until after the driver ->create_rxfh_context call. The driver needs to fill some of the defaults in the context. The failure of rss_fill_reply() is somewhat theoretical, but doesn't take much effort to handle it properly. Call ->remove_rxfh_context(). If the driver's remove callback fails (some implementations like sfc can return real command errors from firmware RPCs) - skip the xa_erase and kfree, leaving the context in the xarray. This matches how ethnl_rss_delete_doit() behaves. Fixes: a166ab7816c5 ("ethtool: rss: support creating contexts via Netlink") Link: https://patch.msgid.link/20260522230647.1705600-7-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: rss: fix hkey leak when indir_size is 0

2026-06-09T10:28:27+00:00

[ Upstream commit 78ccf1a70c6378e1f5073a8c2209b5129067b925 ] rss_get_data_alloc() allocates a single buffer that backs both the indirection table and the hash key, but only assigned data->indir_table when indir_size was nonzero. The expectation was that no driver implements RSS without supporting indirection table but apparently enic does just that (it's the only such in-tree driver). enic has get_rxfh_key_size but no get_rxfh_indir_size. data->indir_table stays as NULL, hkey gets set but rss_get_data_free() kfree(data->indir_table) is a nop and the allocation leaks. Always store the allocation base in data->indir_table so the free path is unambiguous. No caller treats indir_table as a sentinel; everything keys off indir_size. Fixes: 7112a04664bf ("ethtool: add netlink based get rss support") Link: https://patch.msgid.link/20260522230647.1705600-6-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: rss: fix indir_table and hkey leak on get_rxfh failure

2026-06-09T10:28:27+00:00

[ Upstream commit 266297692f97008ca48bc311775c087c59bd7fe3 ] rss_prepare_get() allocates the indirection table and hash key buffer via rss_get_data_alloc(), then calls ops->get_rxfh() to populate them. If get_rxfh() fails, the function returns an error without freeing the allocation. Fixes: 4f038a6a02d2 ("net: ethtool: Don't call .cleanup_data when prepare_data fails") Link: https://patch.msgid.link/20260522230647.1705600-5-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: rss: fix falsely ignoring indir table updates

2026-06-09T10:28:27+00:00

[ Upstream commit 8d60141a32875248ef71d49c9920fa5e2aa40b29 ] rss_set_prep_indir() compares the new indirection table against the current one to determine whether any update is needed. The memcmp call passes data->indir_size as the length argument, but indir_size is the number of u32 entries, not the byte count. Fixes: c0ae03588bbb ("ethtool: rss: initial RSS_SET (indirection table handling)") Link: https://patch.msgid.link/20260522230647.1705600-4-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: rss: add missing errno on RSS context delete

2026-06-09T10:28:26+00:00

[ Upstream commit 3e6c6e9782ff8a8d8ded774b07ad4590cd61d04c ] Remember to set ret before jumping out if someone tries to delete a context on a device which doesn't support contexts. Fixes: fbe09277fa63 ("ethtool: rss: support removing contexts via Netlink") Link: https://patch.msgid.link/20260522230647.1705600-3-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: rss: avoid modifying the RSS context response

2026-06-09T10:28:26+00:00

[ Upstream commit c75b6f6eaacd0b74b832414cc3b9289c3686e941 ] Gemini says that we're modifying the RSS_CREATE response skb. I think it's right, the comment says that unicast() should unshare the skb but I'm not entirely sure what I meant there. netlink_trim() does a copy but only if skb is not well sized (it's at least 2x larger than necessary for the payload). Fixes: a166ab7816c5 ("ethtool: rss: support creating contexts via Netlink") Link: https://patch.msgid.link/20260522230647.1705600-2-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: rss: fix reporting RXH_XFRM_NO_CHANGE as input_xfrm for contexts

2026-02-11T12:41:57+00:00

[ Upstream commit 1c172febdf065375359b2b95156e476bfee30b60 ] Initializing input_xfrm to RXH_XFRM_NO_CHANGE in RSS contexts is problematic. I think I did this to make it clear that the context does not have its own settings applied. But unlike ETH_RSS_HASH_NO_CHANGE which is zero, RXH_XFRM_NO_CHANGE is 0xff. We need to be careful when reading the value back, and remember to treat 0xff as 0. Remove the initialization and switch to storing 0. This lets us also remove the workaround in ethnl_rss_set(). Get side does not need any adjustments and context get no longer reports: RSS input transformation: symmetric-xor: on symmetric-or-xor: on Unknown bits in RSS input transformation: 0xfc for NICs which don't support input_xfrm. Remove the init of hfunc to ETH_RSS_HASH_NO_CHANGE while at it. As already mentioned this is a noop since ETH_RSS_HASH_NO_CHANGE is 0 and struct is zalloc'd. But as this fix exemplifies storing NO_CHANGE as state is fragile. This issue is implicitly caught by running our selftests because YNL in selftests errors out on unknown bits. Fixes: d3e2c7bab124 ("ethtool: rss: support setting input-xfrm via Netlink") Link: https://patch.msgid.link/20260130190311.811129-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: ethtool: use the new helper in rss_set_prep_indir()

2025-09-18T14:07:38+00:00

Refactor rss_set_prep_indir() to utilize the new ethtool_get_rx_ring_count() helper for determining the number of RX rings, replacing the direct use of get_rxnfc with ETHTOOL_GRXRINGS. This ensures compatibility with both legacy and new ethtool_ops interfaces by transparently multiplexing between them. Signed-off-by: Breno Leitao Link: https://patch.msgid.link/20250917-gxrings-v4-7-dae520e2e1cb@debian.org Signed-off-by: Jakub Kicinski

net: ethtool: support including Flow Label in the flow hash for RSS

2025-08-14T09:40:13+00:00

Some modern NICs support including the IPv6 Flow Label in the flow hash for RSS queue selection. This is outside the old "Microsoft spec", but was included in the OCP NIC spec: [ ] RSS include flow label in the hash (configurable) https://www.opencompute.org/w/index.php?title=Core_Offloads#Receive_Side_Scaling RSS Flow Label hashing allows TCP Protective Load Balancing (PLB) to recover from receiver congestion / overload. Rx CPU/queue hotspots are relatively common for data ingest workloads, and so far we had to try to detect the condition at the RPC layer and reopen the connection. PLB lets us change the Flow Label and therefore Rx CPU on RTO, with minimal packet reordering. PLB reaction times are much faster, and can happen at any point in the connection, not just at RPC boundaries. Due to the nature of host processing (relatively long queues, other kernel subsystems masking IRQs for 100s of msecs) the risk of reordering within the host is higher than in the network. But for applications which need it - it is far preferable to potentially persistent overload of subset of queues. It is expected that the hash communicated to the host may change if the Flow Label changes. This may be surprising to some host software, but I don't expect the devices can compute two Toeplitz hashes, one with the Flow Label for queue selection and one without for the rx hash communicated to the host. Besides, changing the hash may potentially help to change the path thru host queues. User can disable NETIF_F_RXHASH if they require a stable flow hash. The name RXH_IP6_FL was chosen based on what we call Flow Label variables in IPv6 processing (fl). I prefer fl_lbl but that appears to be an fbnic-only spelling. We could spell out RXH_IP6_FLOW_LABEL but existing RXH_ defines are a lot more terse. Willem notes [1] that Flow Label is defined as identifying the flow and therefore including both the flow label _and_ the L4 header fields is not generally necessary. But it should not hurt so it's not explicitly prevented if the driver supports hashing on both at the same time. Link: https://lore.kernel.org/68483433b45e2_3cd66f29440@willemb.c.googlers.com.notmuch [1] Signed-off-by: Jakub Kicinski Reviewed-by: Joe Damato Link: https://patch.msgid.link/20250811234212.580748-2-kuba@kernel.org Signed-off-by: Paolo Abeni

ethtool: rss: support removing contexts via Netlink

2025-07-22T01:21:19+00:00

Implement removing additional RSS contexts via Netlink. Technically it'd be possible to shoehorn the delete operation into ethnl_request_ops-compatible handler. The code ends up longer than open coded version, and I think we'll need a custom way of sending notifications at some stage (if we allow tying the context lifetime to the netlink socket, in the future). Link: https://patch.msgid.link/20250717234343.2328602-8-kuba@kernel.org Signed-off-by: Jakub Kicinski