eal: fix macros to align value
Checks
Commit Message
Found an issue while using RTE_ALIGN_MUL_NEAR with an
expression, like as passed in estimate_tsc_freq().
RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
above function as division has more precedence over
substraction.
Fixes: 5120203d753f ("eal: add macros to align value to multiple")
Cc: stable@dpdk.org
Signed-off-by: Harman Kalra <hkalra@marvell.com>
---
lib/librte_eal/include/rte_common.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Comments
09/06/2020 21:17, Harman Kalra:
> Found an issue while using RTE_ALIGN_MUL_NEAR with an
> expression, like as passed in estimate_tsc_freq().
> RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> above function as division has more precedence over
> substraction.
The only change I see is adding parenthesis around v.
Am I right?
> #define RTE_ALIGN_MUL_CEIL(v, mul) \
> - (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> + ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
[...]
> #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> - ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> + (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
[...]
> ({ \
> typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> - (ceil - v) > (v - floor) ? floor : ceil; \
> + (ceil - (v)) > ((v) - floor) ? floor : ceil; \
> })
On Wed, Jun 24, 2020 at 10:13:18AM +0200, Thomas Monjalon wrote:
> External Email
>
> ----------------------------------------------------------------------
> 09/06/2020 21:17, Harman Kalra:
> > Found an issue while using RTE_ALIGN_MUL_NEAR with an
> > expression, like as passed in estimate_tsc_freq().
> > RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> > above function as division has more precedence over
> > substraction.
>
> The only change I see is adding parenthesis around v.
> Am I right?
Yes, parathesis are required if an expression is passed.
>
> > #define RTE_ALIGN_MUL_CEIL(v, mul) \
> > - (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > + ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> [...]
> > #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> > - ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> > + (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
> [...]
> > ({ \
> > typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> > typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> > - (ceil - v) > (v - floor) ? floor : ceil; \
> > + (ceil - (v)) > ((v) - floor) ? floor : ceil; \
> > })
>
>
>
>
24/06/2020 10:24, Harman Kalra:
> On Wed, Jun 24, 2020 at 10:13:18AM +0200, Thomas Monjalon wrote:
> > 09/06/2020 21:17, Harman Kalra:
> > > Found an issue while using RTE_ALIGN_MUL_NEAR with an
> > > expression, like as passed in estimate_tsc_freq().
> > > RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> > > above function as division has more precedence over
> > > substraction.
> >
> > The only change I see is adding parenthesis around v.
> > Am I right?
>
> Yes, parathesis are required if an expression is passed.
I think the commit log needs to be updated.
I don't see the relation between
"division has more precedence over substraction"
and
"parathesis are required if an expression is passed"
> > > #define RTE_ALIGN_MUL_CEIL(v, mul) \
> > > - (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > + ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > [...]
> > > #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> > > - ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > + (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > [...]
> > > ({ \
> > > typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> > > typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> > > - (ceil - v) > (v - floor) ? floor : ceil; \
> > > + (ceil - (v)) > ((v) - floor) ? floor : ceil; \
> > > })
> >
> >
> >
> >
>
On Wed, Jun 24, 2020 at 10:30:18AM +0200, Thomas Monjalon wrote:
> 24/06/2020 10:24, Harman Kalra:
> > On Wed, Jun 24, 2020 at 10:13:18AM +0200, Thomas Monjalon wrote:
> > > 09/06/2020 21:17, Harman Kalra:
> > > > Found an issue while using RTE_ALIGN_MUL_NEAR with an
> > > > expression, like as passed in estimate_tsc_freq().
> > > > RTE_ALIGN_MUL_FLOOR resulted in unexpected value in the
> > > > above function as division has more precedence over
> > > > substraction.
> > >
> > > The only change I see is adding parenthesis around v.
> > > Am I right?
> >
> > Yes, parathesis are required if an expression is passed.
>
> I think the commit log needs to be updated.
> I don't see the relation between
> "division has more precedence over substraction"
> and
> "parathesis are required if an expression is passed"
By "division has more precedence over substraction", I tried to
highlight the issue which resulted in unexpected value, but yes
it is sounding confusing. I will reword the commit message and send
V2.
>
>
> > > > #define RTE_ALIGN_MUL_CEIL(v, mul) \
> > > > - (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > > + ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > [...]
> > > > #define RTE_ALIGN_MUL_FLOOR(v, mul) \
> > > > - ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > > + (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
> > > [...]
> > > > ({ \
> > > > typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
> > > > typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
> > > > - (ceil - v) > (v - floor) ? floor : ceil; \
> > > > + (ceil - (v)) > ((v) - floor) ? floor : ceil; \
> > > > })
> > >
> > >
> > >
> > >
> >
>
>
>
>
>
@@ -295,7 +295,7 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
* than the first parameter.
*/
#define RTE_ALIGN_MUL_CEIL(v, mul) \
- (((v + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
+ ((((v) + (typeof(v))(mul) - 1) / ((typeof(v))(mul))) * (typeof(v))(mul))
/**
* Macro to align a value to the multiple of given value. The resultant
@@ -303,7 +303,7 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
* than the first parameter.
*/
#define RTE_ALIGN_MUL_FLOOR(v, mul) \
- ((v / ((typeof(v))(mul))) * (typeof(v))(mul))
+ (((v) / ((typeof(v))(mul))) * (typeof(v))(mul))
/**
* Macro to align value to the nearest multiple of the given value.
@@ -314,7 +314,7 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
({ \
typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul); \
typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul); \
- (ceil - v) > (v - floor) ? floor : ceil; \
+ (ceil - (v)) > ((v) - floor) ? floor : ceil; \
})
/**