[Outreachy kernel] [PATCH 2/7] staging: most: Using macro DIV_ROUND_UP

Julia Lawall julia.lawall at lip6.fr
Wed Feb 22 07:23:24 UTC 2017



On Tue, 21 Feb 2017, SIMRAN SINGHAL wrote:

>
>
> On Wednesday, February 22, 2017 at 1:28:52 AM UTC+5:30, Julia Lawall wrote:
>
>
>       On Wed, 22 Feb 2017, simran singhal wrote:
>
>       > The macro DIV_ROUND_UP performs the computation (((n) + (d) -
>       1) /(d)).
>       > It clarifies the divisor calculations. This occurence was
>       detected using
>       > the coccinelle script:
>       >
>       > @@
>       > expression e1;
>       > expression e2;
>       > @@
>       > (
>       > - ((e1) + e2 - 1) / (e2)
>       > + DIV_ROUND_UP(e1,e2)
>       > |
>       > - ((e1) + (e2 - 1)) / (e2)
>       > + DIV_ROUND_UP(e1,e2)
>       > )
>
>
>       DIV_ROUND_UP is defined in kernel.h, which defines some other
>       generally
>       useful things.  Maybe there is an opportunity for making rules
>       from some
>       of them also.
>
>
> yes, for sure I will make other rules also, but do I have to include other
> rules in
> this patch only and resend v2.  

It was just a suggestion for future work, not a complaint about this patch
:)

julia

>
>
>       julia
>
>       >
>       > Signed-off-by: simran singhal <singhal... at gmail.com>
>       > ---
>       >  drivers/staging/most/hdm-dim2/dim2_hal.c | 6 +++---
>       >  1 file changed, 3 insertions(+), 3 deletions(-)
>       >
>       > diff --git a/drivers/staging/most/hdm-dim2/dim2_hal.c
>       b/drivers/staging/most/hdm-dim2/dim2_hal.c
>       > index 0b9816c..6824826 100644
>       > --- a/drivers/staging/most/hdm-dim2/dim2_hal.c
>       > +++ b/drivers/staging/most/hdm-dim2/dim2_hal.c
>       > @@ -49,7 +49,7 @@
>       >  #define DBR_SIZE  (16 * 1024) /* specified by IP */
>       >  #define DBR_BLOCK_SIZE  (DBR_SIZE / 32 / DBR_MAP_SIZE)
>       >
>       > -#define ROUND_UP_TO(x, d)  (((x) + (d) - 1) / (d) * (d))
>       > +#define ROUND_UP_TO(x, d)  (DIV_ROUND_UP(x, (d)) * (d))
>       >
>       >  /*
>       --------------------------------------------------------------------------
>       */
>       >  /* generic helper functions and macros */
>       > @@ -117,7 +117,7 @@ static int alloc_dbr(u16 size)
>       >                  return DBR_SIZE; /* out of memory */
>       >
>       >          for (i = 0; i < DBR_MAP_SIZE; i++) {
>       > -                u32 const blocks = (size + DBR_BLOCK_SIZE -
>       1) / DBR_BLOCK_SIZE;
>       > +                u32 const blocks = DIV_ROUND_UP(size,
>       DBR_BLOCK_SIZE);
>       >                  u32 mask = ~((~(u32)0) << blocks);
>       >
>       >                  do {
>       > @@ -137,7 +137,7 @@ static int alloc_dbr(u16 size)
>       >  static void free_dbr(int offs, int size)
>       >  {
>       >          int block_idx = offs / DBR_BLOCK_SIZE;
>       > -        u32 const blocks = (size + DBR_BLOCK_SIZE - 1) /
>       DBR_BLOCK_SIZE;
>       > +        u32 const blocks = DIV_ROUND_UP(size,
>       DBR_BLOCK_SIZE);
>       >          u32 mask = ~((~(u32)0) << blocks);
>       >
>       >          mask <<= block_idx % 32;
>       > --
>       > 2.7.4
>       >
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