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Message-ID: <CBD5806B120ADEEE+20250318054803.462085-1-wangyuli@uniontech.com>
Date: Tue, 18 Mar 2025 13:48:03 +0800
From: WangYuli <wangyuli@...ontech.com>
To: idosch@...dia.com,
petrm@...dia.com,
andrew+netdev@...n.ch,
davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com
Cc: netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
czj2441@....com,
zhanjun@...ontech.com,
niecheng1@...ontech.com,
guanwentao@...ontech.com,
WangYuli <wangyuli@...ontech.com>
Subject: [PATCH net v2] mlxsw: spectrum_acl_bloom_filter: Workaround for some LLVM versions
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-wangyuli@uniontech.com/
Fixes: 7585cacdb978 ("mlxsw: spectrum_acl: Add Bloom filter handling")
Co-developed-by: Zijian Chen <czj2441@....com>
Signed-off-by: Zijian Chen <czj2441@....com>
Co-developed-by: Wentao Guan <guanwentao@...ontech.com>
Signed-off-by: Wentao Guan <guanwentao@...ontech.com>
Suggested-by: Paolo Abeni <pabeni@...hat.com>
Co-developed-by: Ido Schimmel <idosch@...dia.com>
Signed-off-by: Ido Schimmel <idosch@...dia.com>
Tested-by: Ido Schimmel <idosch@...dia.com>
Tested-by: WangYuli <wangyuli@...ontech.com>
Signed-off-by: WangYuli <wangyuli@...ontech.com>
---
Changelog:
*v1->v2:
1. Combine patch #1 and #2 from v1.
2. Take the more simplified change by Ido Schimmel.
3. Append more Co-developed-by, Signed-off-by, Tested-by,
Suggested-by and Fixes tags.
4. Retain reverse Christmas tree order for variables.
---
.../mlxsw/spectrum_acl_bloom_filter.c | 26 +++++++++++++++----
1 file changed, 21 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 a54eedb69a3f..fc8a8cf64ec8 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 +261,12 @@ __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;
--
2.49.0
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