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[146.241.6.87]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43d19541339sm17962415e9.21.2025.03.13.06.52.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 13 Mar 2025 06:52:13 -0700 (PDT) Message-ID: <70a2fa44-c0cf-4dd4-8c17-8cc7abf1fbce@redhat.com> Date: Thu, 13 Mar 2025 14:52:11 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net 1/2] mlxsw: spectrum_acl_bloom_filter: Expand chunk_key_offsets[chunk_index] To: Ido Schimmel , WangYuli Cc: andrew+netdev@lunn.ch, chenlinxuan@uniontech.com, czj2441@163.com, davem@davemloft.net, edumazet@google.com, guanwentao@uniontech.com, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, niecheng1@uniontech.com, petrm@nvidia.com, zhanjun@uniontech.com References: <484364B641C901CD+20250311141025.1624528-1-wangyuli@uniontech.com> <78951564F9FEA017+20250311141701.1626533-1-wangyuli@uniontech.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/12/25 2:20 PM, Ido Schimmel wrote: > On Tue, Mar 11, 2025 at 10:17:00PM +0800, WangYuli wrote: >> 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. > > I'm not sure why the fix suppresses the warning when the warning is > about the destination buffer and the fix is about the source. Can you > check if the below helps? It removes the parameterization from > __mlxsw_sp_acl_bf_key_encode() and instead splits it to two variants. > > 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..3e1e4be72da2 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -110,7 +110,6 @@ static const u16 mlxsw_sp2_acl_bf_crc16_tab[256] = { > * +-----------+----------+-----------------------------------+ > */ > > -#define MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES 0 > #define MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES 18 > #define MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES 20 > > @@ -229,10 +228,9 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) > } > > static void > -__mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > - struct mlxsw_sp_acl_atcam_entry *aentry, > - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, > - u8 key_offset, u8 chunk_key_len, u8 chunk_len) > +mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > + struct mlxsw_sp_acl_atcam_entry *aentry, > + char *output, u8 *len) > { > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > u8 chunk_index, chunk_count, block_count; > @@ -243,30 +241,17 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > chunk_count = 1 + ((block_count - 1) >> 2); > erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > (aregion->region->id << 4)); > - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; > - chunk_index++) { > - memset(chunk, 0, pad_bytes); > - memcpy(chunk + pad_bytes, &erp_region_id, > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { Possibly the compiler is inferring chunck count can be greater then MLXSW_BLOOM_KEY_CHUNKS? something alike: chunk_index = min_t(0, MLXSW_BLOOM_KEY_CHUNKS - chunk_count, u8); Could possibly please it? /P