From: Arnd Bergmann <[email protected]>
With older compilers like gcc-9, the calculation of the vlan
priority field causes a false-positive 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 <<
| ^~~~~~~~~~~
After a change to be16_encode_bits(), the code becomes more
readable to both people and compilers, which avoids the warning.
Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in switchdev")
Suggested-by: Alexander Lobakin <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
---
v2: use be16_encode_bits() instead of a temporary variable.
---
drivers/net/ethernet/intel/ice/ice_tc_lib.c | 8 ++++----
1 file changed, 4 insertions(+), 4 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..76f29a5bf8d7 100644
--- a/drivers/net/ethernet/intel/ice/ice_tc_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
@@ -1455,8 +1455,8 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
if (match.mask->vlan_priority) {
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);
+ be16_encode_bits(match.key->vlan_priority,
+ VLAN_PRIO_MASK);
}
if (match.mask->vlan_tpid)
@@ -1489,8 +1489,8 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
if (match.mask->vlan_priority) {
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);
+ be16_encode_bits(match.key->vlan_priority,
+ VLAN_PRIO_MASK);
}
}
--
2.39.1
From: Arnd Bergmann <[email protected]>
Date: Tue, 14 Feb 2023 16:25:36 +0100
> From: Arnd Bergmann <[email protected]>
>
> With older compilers like gcc-9, the calculation of the vlan
> priority field causes a false-positive 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 <<
> | ^~~~~~~~~~~
>
> After a change to be16_encode_bits(), the code becomes more
> readable to both people and compilers, which avoids the warning.
>
> Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in switchdev")
> Suggested-by: Alexander Lobakin <[email protected]>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> v2: use be16_encode_bits() instead of a temporary variable.
> ---
> drivers/net/ethernet/intel/ice/ice_tc_lib.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 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..76f29a5bf8d7 100644
> --- a/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_tc_lib.c
> @@ -1455,8 +1455,8 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
> if (match.mask->vlan_priority) {
> 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);
> + be16_encode_bits(match.key->vlan_priority,
> + VLAN_PRIO_MASK);
> }
>
> if (match.mask->vlan_tpid)
> @@ -1489,8 +1489,8 @@ ice_parse_cls_flower(struct net_device *filter_dev, struct ice_vsi *vsi,
> if (match.mask->vlan_priority) {
> 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);
> + be16_encode_bits(match.key->vlan_priority,
> + VLAN_PRIO_MASK);
Oh, the patch looks great! Both fixes the issue and cleans up the code
a little bit.
Reviewed-by: Alexander Lobakin <[email protected]>
> }
> }
>
Thanks!
Olek
> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf Of
> Arnd Bergmann
> Sent: Tuesday, February 14, 2023 8:56 PM
> To: Brandeburg, Jesse <[email protected]>; Nguyen, Anthony L
> <[email protected]>; David S. Miller <[email protected]>;
> Eric Dumazet <[email protected]>; Jakub Kicinski <[email protected]>;
> Paolo Abeni <[email protected]>; Martyna Szapar-Mudlaw
> <[email protected]>
> Cc: Lu Wei <[email protected]>; Arnd Bergmann <[email protected]>;
> [email protected]; [email protected]; intel-wired-
> [email protected]
> Subject: [Intel-wired-lan] [PATCH] [v2] ethernet: ice: avoid gcc-9 integer
> overflow warning
>
> From: Arnd Bergmann <[email protected]>
>
> With older compilers like gcc-9, the calculation of the vlan priority field
> causes a false-positive 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 <<
> | ^~~~~~~~~~~
>
> After a change to be16_encode_bits(), the code becomes more readable to
> both people and compilers, which avoids the warning.
>
> Fixes: 34800178b302 ("ice: Add support for VLAN priority filters in
> switchdev")
> Suggested-by: Alexander Lobakin <[email protected]>
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> v2: use be16_encode_bits() instead of a temporary variable.
> ---
> drivers/net/ethernet/intel/ice/ice_tc_lib.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
Tested-by: Sujai Buvaneswaran <[email protected]>