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From: "Wang, Haiyue" <haiyue.wang@intel.com>
To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>,
	"david.marchand@redhat.com" <david.marchand@redhat.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" <dev@dpdk.org>, "stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros
Date: Wed, 12 May 2021 01:13:41 +0000	[thread overview]
Message-ID: <BN8PR11MB3795CA34630FCDC62BB28B22F7529@BN8PR11MB3795.namprd11.prod.outlook.com> (raw)
In-Reply-To: <PH0PR18MB40862B79DF886E8B04047526DE539@PH0PR18MB4086.namprd18.prod.outlook.com>

> -----Original Message-----
> From: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
> Sent: Tuesday, May 11, 2021 16:45
> To: Wang, Haiyue <haiyue.wang@intel.com>; david.marchand@redhat.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; stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros
> 
> >> -----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. : - (
> >
> 
> RTE_ALIGN_CEIL is prone to macro side effects since it uses align twice in the macro.
> To fix it RTE_ALIGN_CEIL first expands the val and align values to temporary values
> and then calls ALIGN_FLOOR.
> Due to this we can no longer use ALIGN/ALIGN_CEIL in static array declarations
> 
> Example:
> In file included from ../lib/eal/x86/include/rte_atomic.h:13,
>                  from ../examples/bbdev_app/main.c:21:
> ../lib/eal/include/rte_common.h:312:15: error: braced-group within expression allowed only inside a
> function
>   __extension__({                                                        \
>                ^
> ../examples/bbdev_app/main.c:48:18: note: in expansion of macro 'RTE_ALIGN_CEIL'
>  #define NCB (3 * RTE_ALIGN_CEIL(K + 4, 32))
>                   ^~~~~~~~~~~~~~
> ../examples/bbdev_app/main.c:145:23: note: in expansion of macro 'NCB'
>   uint8_t llr_temp_buf[NCB];
> 
> To workaround this I had to call RTE_ALIGN_FLOOR for known constants directly.
> 

Clear now, thanks.

For Intel PMDs,

Acked-by: Haiyue Wang <haiyue.wang@intel.com>


BTW, I'm wondering that we can explicitly define the macro with type style
like RTE_ALIGN_CEIL_TYPE, so that people can notice the side effects directly,
and choose the right ALIGN macro.

And can still use ALIGN/ALIGN_CEIL in static array declarations, which is
very simple.

Just my thinking. ;-)

> >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


  reply	other threads:[~2021-05-12  1:13 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-09 17:18 [dpdk-dev] [PATCH 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-09 17:18 ` [dpdk-dev] [PATCH 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-09 19:39   ` Stephen Hemminger
2021-05-10  9:50     ` [dpdk-dev] [EXT] " Pavan Nikhilesh Bhagavatula
2021-05-10 13:34       ` David Marchand
2021-05-10 14:02 ` [dpdk-dev] [PATCH v2 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-10 14:02   ` [dpdk-dev] [PATCH v2 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-10 19:40   ` [dpdk-dev] [PATCH v3 1/2] eal: fix side effects in align mul macros pbhagavatula
2021-05-10 19:40     ` [dpdk-dev] [PATCH v3 2/2] eal: fix side effects in ptr align macros pbhagavatula
2021-05-11  2:12       ` Wang, Haiyue
2021-05-11  8:44         ` Pavan Nikhilesh Bhagavatula
2021-05-12  1:13           ` Wang, Haiyue [this message]
2023-07-03 18:55     ` [PATCH] eal: avoid issues in macro expansion of alignment Stephen Hemminger
2023-07-03 23:23       ` [PATCH v2] " Stephen Hemminger
2023-07-04  8:43         ` Morten Brørup
2023-07-04 16:00           ` Stephen Hemminger
2023-07-04 22:16             ` Morten Brørup
2023-07-14 16:37               ` Stephen Hemminger
2023-07-04 16:01     ` [dpdk-dev] [PATCH v3 1/2] eal: fix side effects in align mul macros Stephen Hemminger

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