6.14-stable review patch. If anyone has any objections, please let me know.
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From: WangYuli wangyuli@uniontech.com
[ Upstream commit 4af9939a4977e05ccaaa645848f6208e82e06c61 ]
This is a workaround to mitigate a compiler anomaly.
During LLVM toolchain compilation of this driver on s390x architecture, an unreasonable __write_overflow_field warning occurs.
Contextually, chunk_index is restricted to 0, 1 or 2. By expanding these possibilities, the compile warning is suppressed.
Fix follow error with clang-19 when -Werror: In file included from drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c:5: In file included from ./include/linux/gfp.h:7: In file included from ./include/linux/mmzone.h:8: In file included from ./include/linux/spinlock.h:63: In file included from ./include/linux/lockdep.h:14: In file included from ./include/linux/smp.h:13: In file included from ./include/linux/cpumask.h:12: In file included from ./include/linux/bitmap.h:13: In file included from ./include/linux/string.h:392: ./include/linux/fortify-string.h:571:4: error: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning] 571 | __write_overflow_field(p_size_field, size); | ^ 1 error generated.
According to the testing, we can be fairly certain that this is a clang compiler bug, impacting only clang-19 and below. Clang versions 20 and 21 do not exhibit this behavior.
Link: https://lore.kernel.org/all/484364B641C901CD+20250311141025.1624528-1-wangyu... Fixes: 7585cacdb978 ("mlxsw: spectrum_acl: Add Bloom filter handling") Co-developed-by: Zijian Chen czj2441@163.com Signed-off-by: Zijian Chen czj2441@163.com Co-developed-by: Wentao Guan guanwentao@uniontech.com Signed-off-by: Wentao Guan guanwentao@uniontech.com Suggested-by: Paolo Abeni pabeni@redhat.com Co-developed-by: Ido Schimmel idosch@nvidia.com Signed-off-by: Ido Schimmel idosch@nvidia.com Tested-by: Ido Schimmel idosch@nvidia.com Tested-by: WangYuli wangyuli@uniontech.com Signed-off-by: WangYuli wangyuli@uniontech.com Link: https://patch.msgid.link/A1858F1D36E653E0+20250318103654.708077-1-wangyuli@u... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../mlxsw/spectrum_acl_bloom_filter.c | 27 +++++++++++++++---- 1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c index a54eedb69a3f5..067f0055a55af 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c @@ -212,7 +212,22 @@ static const u8 mlxsw_sp4_acl_bf_crc6_tab[256] = { * This array defines key offsets for easy access when copying key blocks from * entry key to Bloom filter chunk. */ -static const u8 chunk_key_offsets[MLXSW_BLOOM_KEY_CHUNKS] = {2, 20, 38}; +static char * +mlxsw_sp_acl_bf_enc_key_get(struct mlxsw_sp_acl_atcam_entry *aentry, + u8 chunk_index) +{ + switch (chunk_index) { + case 0: + return &aentry->ht_key.enc_key[2]; + case 1: + return &aentry->ht_key.enc_key[20]; + case 2: + return &aentry->ht_key.enc_key[38]; + default: + WARN_ON_ONCE(1); + return &aentry->ht_key.enc_key[0]; + } +}
static u16 mlxsw_sp2_acl_bf_crc16_byte(u16 crc, u8 c) { @@ -235,9 +250,10 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, u8 key_offset, u8 chunk_key_len, u8 chunk_len) { struct mlxsw_afk_key_info *key_info = aregion->region->key_info; - u8 chunk_index, chunk_count, block_count; + u8 chunk_index, chunk_count; char *chunk = output; __be16 erp_region_id; + u32 block_count;
block_count = mlxsw_afk_key_info_blocks_count_get(key_info); chunk_count = 1 + ((block_count - 1) >> 2); @@ -245,12 +261,13 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, (aregion->region->id << 4)); for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; chunk_index++) { + char *enc_key; + memset(chunk, 0, pad_bytes); memcpy(chunk + pad_bytes, &erp_region_id, sizeof(erp_region_id)); - memcpy(chunk + key_offset, - &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], - chunk_key_len); + enc_key = mlxsw_sp_acl_bf_enc_key_get(aentry, chunk_index); + memcpy(chunk + key_offset, enc_key, chunk_key_len); chunk += chunk_len; } *len = chunk_count * chunk_len;