Messages in this thread Patch in this message | | | From | Marco Bonelli <> | Subject | [PATCH] ethtool: Fix and optimize ethtool_convert_link_mode_to_legacy_u32() | Date | Wed, 25 May 2022 00:38:19 +0200 |
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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
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