lkml.org 
[lkml]   [2022]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] ethtool: Fix and optimize ethtool_convert_link_mode_to_legacy_u32()
Date
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@mebeim.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
\
 
 \ /
  Last update: 2022-05-25 00:43    [W:0.228 / U:0.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site