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From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
	intel-wired-lan@lists.osuosl.org,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	linux-kernel@vger.kernel.org,
	Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>,
	Eric Dumazet <edumazet@google.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [Intel-wired-lan] [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning
Date: Tue, 14 Feb 2023 16:40:23 +0100	[thread overview]
Message-ID: <Y+urZ09WHJjRoYFs@boxer> (raw)
In-Reply-To: <20230214132002.1498163-1-arnd@kernel.org>

On Tue, Feb 14, 2023 at 02:19:49PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> With older compilers like gcc-9, the calculation of the vlan
> priority field causes a warning from the byteswap:
> 
> In file included from drivers/net/ethernet/intel/ice/ice_tc_lib.c:4:
> drivers/net/ethernet/intel/ice/ice_tc_lib.c: In function 'ice_parse_cls_flower':
> include/uapi/linux/swab.h:15:15: error: integer overflow in expression '(int)(short unsigned int)((int)match.key-><U67c8>.<U6698>.vlan_priority << 13) & 57344 & 255' of type 'int' results in '0' [-Werror=overflow]
>    15 |  (((__u16)(x) & (__u16)0x00ffU) << 8) |   \
>       |   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
> include/uapi/linux/swab.h:106:2: note: in expansion of macro '___constant_swab16'
>   106 |  ___constant_swab16(x) :   \
>       |  ^~~~~~~~~~~~~~~~~~
> include/uapi/linux/byteorder/little_endian.h:42:43: note: in expansion of macro '__swab16'
>    42 | #define __cpu_to_be16(x) ((__force __be16)__swab16((x)))
>       |                                           ^~~~~~~~
> include/linux/byteorder/generic.h:96:21: note: in expansion of macro '__cpu_to_be16'
>    96 | #define cpu_to_be16 __cpu_to_be16
>       |                     ^~~~~~~~~~~~~
> drivers/net/ethernet/intel/ice/ice_tc_lib.c:1458:5: note: in expansion of macro 'cpu_to_be16'
>  1458 |     cpu_to_be16((match.key->vlan_priority <<
>       |     ^~~~~~~~~~~
> 
> The code looks correct to me, so just avoid the warning by replacing
> the macro expansion with an intermediate variable.
> 
> Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in switchdev")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

> ---
>  drivers/net/ethernet/intel/ice/ice_tc_lib.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_tc_lib.c b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> index 6b48cbc049c6..e9932446185c 100644
> --- a/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> @@ -1453,10 +1453,9 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
>  		}
>  
>  		if (match.mask->vlan_priority) {
> +			u16 prio = (match.key->vlan_priority << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK;

nit: usually for such scoped stack var we follow the declaration with an
empty line

>  			fltr->flags |= ICE_TC_FLWR_FIELD_VLAN_PRIO;
> -			headers->vlan_hdr.vlan_prio =
> -				cpu_to_be16((match.key->vlan_priority <<
> -					     VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK);
> +			headers->vlan_hdr.vlan_prio = cpu_to_be16(prio);
>  		}
>  
>  		if (match.mask->vlan_tpid)
> @@ -1487,10 +1486,9 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
>  		}
>  
>  		if (match.mask->vlan_priority) {
> +			u16 prio = (match.key->vlan_priority << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK;
>  			fltr->flags |= ICE_TC_FLWR_FIELD_CVLAN_PRIO;
> -			headers->cvlan_hdr.vlan_prio =
> -				cpu_to_be16((match.key->vlan_priority <<
> -					     VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK);
> +			headers->cvlan_hdr.vlan_prio = cpu_to_be16(prio);
>  		}
>  	}
>  
> -- 
> 2.39.1
> 
_______________________________________________
Intel-wired-lan mailing list
Intel-wired-lan@osuosl.org
https://lists.osuosl.org/mailman/listinfo/intel-wired-lan

WARNING: multiple messages have this Message-ID (diff)
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Martyna Szapar-Mudlaw <martyna.szapar-mudlaw@linux.intel.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Marcin Szycik <marcin.szycik@linux.intel.com>,
	Amritha Nambiar <amritha.nambiar@intel.com>,
	Michal Swiatkowski <michal.swiatkowski@linux.intel.com>,
	Wojciech Drewek <wojciech.drewek@intel.com>,
	<intel-wired-lan@lists.osuosl.org>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning
Date: Tue, 14 Feb 2023 16:40:23 +0100	[thread overview]
Message-ID: <Y+urZ09WHJjRoYFs@boxer> (raw)
In-Reply-To: <20230214132002.1498163-1-arnd@kernel.org>

On Tue, Feb 14, 2023 at 02:19:49PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> With older compilers like gcc-9, the calculation of the vlan
> priority field causes a warning from the byteswap:
> 
> In file included from drivers/net/ethernet/intel/ice/ice_tc_lib.c:4:
> drivers/net/ethernet/intel/ice/ice_tc_lib.c: In function 'ice_parse_cls_flower':
> include/uapi/linux/swab.h:15:15: error: integer overflow in expression '(int)(short unsigned int)((int)match.key-><U67c8>.<U6698>.vlan_priority << 13) & 57344 & 255' of type 'int' results in '0' [-Werror=overflow]
>    15 |  (((__u16)(x) & (__u16)0x00ffU) << 8) |   \
>       |   ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
> include/uapi/linux/swab.h:106:2: note: in expansion of macro '___constant_swab16'
>   106 |  ___constant_swab16(x) :   \
>       |  ^~~~~~~~~~~~~~~~~~
> include/uapi/linux/byteorder/little_endian.h:42:43: note: in expansion of macro '__swab16'
>    42 | #define __cpu_to_be16(x) ((__force __be16)__swab16((x)))
>       |                                           ^~~~~~~~
> include/linux/byteorder/generic.h:96:21: note: in expansion of macro '__cpu_to_be16'
>    96 | #define cpu_to_be16 __cpu_to_be16
>       |                     ^~~~~~~~~~~~~
> drivers/net/ethernet/intel/ice/ice_tc_lib.c:1458:5: note: in expansion of macro 'cpu_to_be16'
>  1458 |     cpu_to_be16((match.key->vlan_priority <<
>       |     ^~~~~~~~~~~
> 
> The code looks correct to me, so just avoid the warning by replacing
> the macro expansion with an intermediate variable.
> 
> Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in switchdev")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

> ---
>  drivers/net/ethernet/intel/ice/ice_tc_lib.c | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_tc_lib.c b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> index 6b48cbc049c6..e9932446185c 100644
> --- a/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> @@ -1453,10 +1453,9 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
>  		}
>  
>  		if (match.mask->vlan_priority) {
> +			u16 prio = (match.key->vlan_priority << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK;

nit: usually for such scoped stack var we follow the declaration with an
empty line

>  			fltr->flags |= ICE_TC_FLWR_FIELD_VLAN_PRIO;
> -			headers->vlan_hdr.vlan_prio =
> -				cpu_to_be16((match.key->vlan_priority <<
> -					     VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK);
> +			headers->vlan_hdr.vlan_prio = cpu_to_be16(prio);
>  		}
>  
>  		if (match.mask->vlan_tpid)
> @@ -1487,10 +1486,9 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
>  		}
>  
>  		if (match.mask->vlan_priority) {
> +			u16 prio = (match.key->vlan_priority << VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK;
>  			fltr->flags |= ICE_TC_FLWR_FIELD_CVLAN_PRIO;
> -			headers->cvlan_hdr.vlan_prio =
> -				cpu_to_be16((match.key->vlan_priority <<
> -					     VLAN_PRIO_SHIFT) & VLAN_PRIO_MASK);
> +			headers->cvlan_hdr.vlan_prio = cpu_to_be16(prio);
>  		}
>  	}
>  
> -- 
> 2.39.1
> 

  parent reply	other threads:[~2023-02-14 15:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-14 13:19 [Intel-wired-lan] [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning Arnd Bergmann
2023-02-14 13:19 ` Arnd Bergmann
2023-02-14 14:19 ` [Intel-wired-lan] " Alexander Lobakin
2023-02-14 14:19   ` Alexander Lobakin
2023-02-14 15:40 ` Maciej Fijalkowski [this message]
2023-02-14 15:40   ` Maciej Fijalkowski
2023-02-15 10:58 ` [Intel-wired-lan] " David Laight
2023-02-15 10:58   ` David Laight

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