From 19d62f5eeaa0fd912cc179530084403f90a5535a Mon Sep 17 00:00:00 2001 From: Marco Bonelli Date: Thu, 9 Jun 2022 15:49:01 +0200 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 Link: https://lore.kernel.org/r/20220609134900.11201-1-marco@mebeim.net Signed-off-by: Jakub Kicinski --- 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 d05ff6a17a1f..6a7308de192d 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);