Re: [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros

["Wang, Haiyue" <haiyue.wang@intel.com>]

> -----Original Message-----
> From: pbhagavatula@marvell.com <pbhagavatula@marvell.com>
> Sent: Tuesday, May 11, 2021 03:40
> To: david.marchand@redhat.com; Wang, Haiyue <haiyue.wang@intel.com>; Matan Azrad <matan@nvidia.com>;
> Shahaf Shuler <shahafs@nvidia.com>; Viacheslav Ovsiienko <viacheslavo@nvidia.com>; Jiawen Wu
> <jiawenwu@trustnetic.com>; Jian Wang <jianwang@trustnetic.com>; Chautru, Nicolas
> <nicolas.chautru@intel.com>; Thomas Monjalon <thomas@monjalon.net>; Yigit, Ferruh
> <ferruh.yigit@intel.com>; Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Cc: dev@dpdk.org; Pavan Nikhilesh <pbhagavatula@marvell.com>; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros
> 
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> 
> Avoid expanding parameters inside RTE_*_ALIGN macros.
> Update common_autotest to detect macro side effects.
> Workaround static arrays relying on RTE_ALIGN macros.
> 
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>  app/test/test_common.c           |  6 ++++++
>  drivers/net/e1000/e1000_ethdev.h |  7 ++++---
>  drivers/net/ixgbe/ixgbe_ethdev.h |  6 ++++--
>  drivers/net/mlx5/mlx5_rxtx_vec.h |  7 ++++---
>  drivers/net/txgbe/txgbe_ethdev.h |  6 ++++--
>  examples/bbdev_app/main.c        |  2 +-
>  lib/eal/include/rte_common.h     | 17 +++++++++++++----
>  lib/ethdev/rte_eth_ctrl.h        |  5 +++--
>  8 files changed, 39 insertions(+), 17 deletions(-)
> 
> diff --git a/app/test/test_common.c b/app/test/test_common.c
> index 0dbb87e741..9efe3b10f9 100644
> --- a/app/test/test_common.c
> +++ b/app/test/test_common.c
> @@ -69,6 +69,12 @@ test_macros(int __rte_unused unused_parm)
>  	TEST_SIDE_EFFECT_2(RTE_PTR_ADD, void *, size_t);
>  	TEST_SIDE_EFFECT_2(RTE_PTR_DIFF, void *, void *);
>  	TEST_SIDE_EFFECT_2(RTE_PTR_SUB, void *, size_t);
> +	TEST_SIDE_EFFECT_2(RTE_PTR_ALIGN, void *, size_t);
> +	TEST_SIDE_EFFECT_2(RTE_PTR_ALIGN_CEIL, void *, size_t);
> +	TEST_SIDE_EFFECT_2(RTE_PTR_ALIGN_FLOOR, void *, size_t);
> +	TEST_SIDE_EFFECT_2(RTE_ALIGN, unsigned int, unsigned int);
> +	TEST_SIDE_EFFECT_2(RTE_ALIGN_CEIL, unsigned int, unsigned int);
> +	TEST_SIDE_EFFECT_2(RTE_ALIGN_FLOOR, unsigned int, unsigned int);
>  	TEST_SIDE_EFFECT_2(RTE_ALIGN_MUL_CEIL, unsigned int, unsigned int);
>  	TEST_SIDE_EFFECT_2(RTE_ALIGN_MUL_FLOOR, unsigned int, unsigned int);
>  	TEST_SIDE_EFFECT_2(RTE_ALIGN_MUL_NEAR, unsigned int, unsigned int);
> diff --git a/drivers/net/e1000/e1000_ethdev.h b/drivers/net/e1000/e1000_ethdev.h
> index 3b4d9c3ee6..155d825d89 100644
> --- a/drivers/net/e1000/e1000_ethdev.h
> +++ b/drivers/net/e1000/e1000_ethdev.h
> @@ -332,9 +332,10 @@ struct igb_eth_syn_filter_ele {
>  };
> 
>  #define IGB_FLEX_FILTER_MAXLEN	128	/**< bytes to use in flex filter. */
> -#define IGB_FLEX_FILTER_MASK_SIZE	\
> -	(RTE_ALIGN(IGB_FLEX_FILTER_MAXLEN, CHAR_BIT) / CHAR_BIT)
> -					/**< mask bytes in flex filter. */
> +#define IGB_FLEX_FILTER_MASK_SIZE                                              \
> +	(RTE_ALIGN_FLOOR(IGB_FLEX_FILTER_MAXLEN + (CHAR_BIT - 1), CHAR_BIT) /  \
> +	 CHAR_BIT)
> +/**< mask bytes in flex filter. */
> 

Since:
RTE_ALIGN --> RTE_ALIGN_CEIL(val, align) --> RTE_ALIGN_FLOOR(...)

Why only change 'RTE_ALIGN_CEIL', but then call 'RTE_ALIGN_FLOOR' directly ?
Sorry, can't get the point. : - (

Why not change 'RTE_ALIGN' if it has issue ?

> 
> diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
> index a142596587..6acd067b5c 100644
> --- a/lib/eal/include/rte_common.h
> +++ b/lib/eal/include/rte_common.h
> @@ -294,8 +294,13 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
>   * point to an address no lower than the first parameter. Second parameter
>   * must be a power-of-two value.
>   */
> -#define RTE_PTR_ALIGN_CEIL(ptr, align) \
> -	RTE_PTR_ALIGN_FLOOR((typeof(ptr))RTE_PTR_ADD(ptr, (align) - 1), align)
> +#define RTE_PTR_ALIGN_CEIL(ptr, align)                                         \
> +	__extension__({                                                        \
> +		typeof(ptr) _pc = (ptr);                                       \
> +		typeof(align) _ac = (align);                                   \
> +		RTE_PTR_ALIGN_FLOOR((typeof(ptr))RTE_PTR_ADD(_pc, _ac - 1),    \
> +				    _ac);                                      \
> +	})
> 
>  /**
>   * Macro to align a value to a given power-of-two. The resultant value
> @@ -303,8 +308,12 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
>   * than the first parameter. Second parameter must be a power-of-two
>   * value.
>   */
> -#define RTE_ALIGN_CEIL(val, align) \
> -	RTE_ALIGN_FLOOR(((val) + ((typeof(val)) (align) - 1)), align)
> +#define RTE_ALIGN_CEIL(val, align)                                             \
> +	__extension__({                                                        \
> +		typeof(val) _vc = (val);                                       \
> +		typeof(val) _ac = (typeof(val))(align);                        \
> +		RTE_ALIGN_FLOOR((_vc + _ac - 1), _ac);                         \
> +	})
> 
>  /**
>   * Macro to align a pointer to a given power-of-two. The resultant
> diff --git a/lib/ethdev/rte_eth_ctrl.h b/lib/ethdev/rte_eth_ctrl.h
> index 42652f9cce..863e56170b 100644
> --- a/lib/ethdev/rte_eth_ctrl.h
> +++ b/lib/ethdev/rte_eth_ctrl.h
> @@ -431,8 +431,9 @@ enum rte_fdir_mode {
>  };
> 
>  #define UINT64_BIT (CHAR_BIT * sizeof(uint64_t))
> -#define RTE_FLOW_MASK_ARRAY_SIZE \
> -	(RTE_ALIGN(RTE_ETH_FLOW_MAX, UINT64_BIT)/UINT64_BIT)
> +#define RTE_FLOW_MASK_ARRAY_SIZE                                               \
> +	(RTE_ALIGN_FLOOR(RTE_ETH_FLOW_MAX + (UINT64_BIT - 1), UINT64_BIT) /    \
> +	 UINT64_BIT)
> 
>  /**
>   * A structure used to get the information of flow director filter.
> --
> 2.17.1