From 3a728898df138112d121e88a7afdfedd135f26a6 Mon Sep 17 00:00:00 2001 From: Petr Oros Date: Mon, 23 Nov 2020 17:16:43 +0100 Subject: [PATCH 20/78] net: ena: rss: store hash function as values and not bits Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1861967 Upstream commit(s): commit 4844470d472d660c26149ad764da2406adb13423 Author: Arthur Kiyanovski Date: Tue Feb 11 15:17:46 2020 +0000 net: ena: rss: store hash function as values and not bits The device receives, stores and retrieves the hash function value as bits and not as their enum value. The bug: * In ena_com_set_hash_function() we set cmd.u.flow_hash_func.selected_func to the bit value of rss->hash_func. (1 << rss->hash_func) * In ena_com_get_hash_function() we retrieve the hash function and store it's bit value in rss->hash_func. (Now the bit value of rss->hash_func is stored in rss->hash_func instead of it's enum value) The fix: This commit fixes the issue by converting the retrieved hash function values from the device to the matching enum value of the set bit using ffs(). ffs() finds the first set bit's index in a word. Since the function returns 1 for the LSB's index, we need to subtract 1 from the returned value (note that BIT(0) is 1). Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Sameeh Jubran Signed-off-by: Arthur Kiyanovski Signed-off-by: David S. Miller Signed-off-by: Petr Oros --- drivers/net/ethernet/amazon/ena/ena_com.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c index 22e24763c4e2..2f9af8762b52 100644 --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -2370,7 +2370,11 @@ int ena_com_get_hash_function(struct ena_com_dev *ena_dev, if (unlikely(rc)) return rc; - rss->hash_func = get_resp.u.flow_hash_func.selected_func; + /* ffs() returns 1 in case the lsb is set */ + rss->hash_func = ffs(get_resp.u.flow_hash_func.selected_func); + if (rss->hash_func) + rss->hash_func--; + if (func) *func = rss->hash_func; -- 2.13.6