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authorEric Dumazet <edumazet@google.com>2026-01-22 19:03:49 +0000
committerJakub Kicinski <kuba@kernel.org>2026-01-25 13:20:46 -0800
commit37b0ea8fef56ccc29bd5a07f235ac218f7f98379 (patch)
tree396c74855396abd75ba9ee57f18375679cde656f /net
parenta113a8ac5086cff408dc3320fbc0ec06a51f0897 (diff)
net: expand NETDEV_RSS_KEY_LEN to 256 bytes
NETDEV_RSS_KEY_LEN has been set to 52 bytes in 2014, until now. Jakub suggested we bump the size to 128 bytes or more. Some drivers (like idpf) were already working around the core limit. Since this change might cause some issues in admin scripts, bump it directly to 256 in one go. tjbp26:~# cat /proc/sys/net/core/netdev_rss_key | wc -c 768 tjbp26:~# ethtool -x eth1 RX flow hash indirection table for eth1 with 32 RX ring(s): ... RSS hash key: fe:16:5b:2f:93:85:c2:c9:c1:ef:bd:60:c6:e0:2b:99:4d:bf:b7:14:c8:1e:8d:cb:31:17:51:da:55:eb:91:d9:9e:f9:89:9b:44:a1:dc:08:72:3a:b3:d6:31:86:9a:fe:02:3a:0d:eb:a1:7c:f5:a3:51:3b:08:56:c9:3f:71:69:01:ba:70:38 RSS hash function: toeplitz: on xor: off crc32: off Suggested-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/netdev/20260122075206.504ec591@kernel.org/ Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://patch.msgid.link/20260122190349.2771064-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/sysctl_net_core.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 05dd55cf8b58..0f761d4b9447 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -325,10 +325,16 @@ static int proc_do_dev_weight(const struct ctl_table *table, int write,
static int proc_do_rss_key(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
- struct ctl_table fake_table;
char buf[NETDEV_RSS_KEY_LEN * 3];
+ struct ctl_table fake_table;
+ char *pos = buf;
+
+ for (int i = 0; i < NETDEV_RSS_KEY_LEN; i++) {
+ pos = hex_byte_pack(pos, netdev_rss_key[i]);
+ *pos++ = ':';
+ }
+ *(--pos) = 0;
- snprintf(buf, sizeof(buf), "%*phC", NETDEV_RSS_KEY_LEN, netdev_rss_key);
fake_table.data = buf;
fake_table.maxlen = sizeof(buf);
return proc_dostring(&fake_table, write, buffer, lenp, ppos);