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Message-Id: <20220609134900.11201-1-marco@mebeim.net>
Date: Thu, 9 Jun 2022 15:49:01 +0200
From: Marco Bonelli <marco@...eim.net>
To: netdev@...r.kernel.org
Cc: Marco Bonelli <marco@...eim.net>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] ethtool: Fix and simplify ethtool_convert_link_mode_to_legacy_u32()
Fix the implementation of ethtool_convert_link_mode_to_legacy_u32(), which
is supposed to return false if src has bits higher than 31 set. The current
implementation uses the complement of bitmap_fill(ext, 32) to test high
bits of src, which is wrong as bitmap_fill() fills _with long granularity_,
and sizeof(long) can be > 4. No users of this function currently check the
return value, so the bug was dormant.
Also remove the check for __ETHTOOL_LINK_MODE_MASK_NBITS > 32, as the enum
ethtool_link_mode_bit_indices contains far beyond 32 values. Using
find_next_bit() to test the src bitmask works regardless of this anyway.
Signed-off-by: Marco Bonelli <marco@...eim.net>
---
net/ethtool/ioctl.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 326e14ee05db..7fb3f3fd6f3c 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -369,22 +369,9 @@ EXPORT_SYMBOL(ethtool_convert_legacy_u32_to_link_mode);
bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
const unsigned long *src)
{
- bool retval = true;
-
- /* TODO: following test will soon always be true */
- if (__ETHTOOL_LINK_MODE_MASK_NBITS > 32) {
- __ETHTOOL_DECLARE_LINK_MODE_MASK(ext);
-
- linkmode_zero(ext);
- bitmap_fill(ext, 32);
- bitmap_complement(ext, ext, __ETHTOOL_LINK_MODE_MASK_NBITS);
- if (linkmode_intersects(ext, src)) {
- /* src mask goes beyond bit 31 */
- retval = false;
- }
- }
*legacy_u32 = src[0];
- return retval;
+ return find_next_bit(src, __ETHTOOL_LINK_MODE_MASK_NBITS, 32) ==
+ __ETHTOOL_LINK_MODE_MASK_NBITS;
}
EXPORT_SYMBOL(ethtool_convert_link_mode_to_legacy_u32);
--
2.30.2
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