* Re: [Intel-wired-lan] [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning
2023-02-14 13:19 [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning Arnd Bergmann
@ 2023-02-14 14:19 ` Alexander Lobakin
2023-02-14 15:40 ` Maciej Fijalkowski
2023-02-15 10:58 ` David Laight
2 siblings, 0 replies; 4+ messages in thread
From: Alexander Lobakin @ 2023-02-14 14:19 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Arnd Bergmann, Jesse Brandeburg, Tony Nguyen, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Martyna Szapar-Mudlaw,
netdev, linux-kernel, intel-wired-lan
From: Arnd Bergmann <arnd@kernel.org>
Date: Tue, 14 Feb 2023 14:19:49 +0100
> 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")
Should it have "Fixes:" tag if the code itself is correct?
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> 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;
Maybe just u32?
Also, I'd go for FIELD_PREP() here. Even be16_encode_bits(). Or does it
have the same problem on GCC 9?
__be16 pri;
pri = be16_encode_bits(match.key->vlan_priority,
VLAN_PRIO_MASK);
headers->vlan_hdr.vlan_prio = pri;
But I suspect you (or somebody else) will say "please don't mix fixes
and improvements" :D Altho I'd go for this one if it silences the warning.
> 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);
^
> }
> }
>
Thanks,
Olek
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning
2023-02-14 13:19 [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning Arnd Bergmann
2023-02-14 14:19 ` [Intel-wired-lan] " Alexander Lobakin
@ 2023-02-14 15:40 ` Maciej Fijalkowski
2023-02-15 10:58 ` David Laight
2 siblings, 0 replies; 4+ messages in thread
From: Maciej Fijalkowski @ 2023-02-14 15:40 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Jesse Brandeburg, Tony Nguyen, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Martyna Szapar-Mudlaw, Arnd Bergmann,
Marcin Szycik, Amritha Nambiar, Michal Swiatkowski,
Wojciech Drewek, intel-wired-lan, netdev, linux-kernel
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
>
^ permalink raw reply [flat|nested] 4+ messages in thread* RE: [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning
2023-02-14 13:19 [PATCH] ethernet: ice: avoid gcc-9 integer overflow warning Arnd Bergmann
2023-02-14 14:19 ` [Intel-wired-lan] " Alexander Lobakin
2023-02-14 15:40 ` Maciej Fijalkowski
@ 2023-02-15 10:58 ` David Laight
2 siblings, 0 replies; 4+ messages in thread
From: David Laight @ 2023-02-15 10:58 UTC (permalink / raw)
To: 'Arnd Bergmann', Jesse Brandeburg, Tony Nguyen,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Martyna Szapar-Mudlaw
Cc: Arnd Bergmann, Marcin Szycik, Amritha Nambiar, Michal Swiatkowski,
Wojciech Drewek, intel-wired-lan@lists.osuosl.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
From: Arnd Bergmann
> Sent: 14 February 2023 13:20
>
> 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:
>
...
>
> Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in switchdev")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> 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;
> 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);
> }
Is there something that will do:
unsigned int pri = match.key->vlan_priority & (VLAN_PRIO_MASK >> VLAN_PRIO_SHIFT);
headers->vlan_hdr.vlan_prio = pri << (VLAN_PRIO_SHIFT ^ (le ? 8 : 0));
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply [flat|nested] 4+ messages in thread