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

From: Julia Lawall
Date: Wed Feb 22 2017 - 02:24:05 EST




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. ÂMaybe 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. Â

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

julia

>
>
> julia
>
> >
> > Signed-off-by: simran singhal <singhal...@xxxxxxxxx>
> > ---
> > Âdrivers/staging/most/hdm-dim2/dim2_hal.c | 6 +++---
> > Â1 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 @@
> > Â#define DBR_SIZE Â(16 * 1024) /* specified by IP */
> > Â#define DBR_BLOCK_SIZE Â(DBR_SIZE / 32 / DBR_MAP_SIZE)
> >
> > -#define ROUND_UP_TO(x, d) Â(((x) + (d) - 1) / (d) * (d))
> > +#define ROUND_UP_TO(x, d) Â(DIV_ROUND_UP(x, (d)) * (d))
> >
> > Â/*
> --------------------------------------------------------------------------
> */
> > Â/* generic helper functions and macros */
> > @@ -117,7 +117,7 @@ static int alloc_dbr(u16 size)
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂreturn DBR_SIZE; /* out of memory */
> >
> > ÂÂÂÂÂÂÂÂÂfor (i = 0; i < DBR_MAP_SIZE; i++) {
> > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂu32 const blocks = (size + DBR_BLOCK_SIZE -
> 1) / DBR_BLOCK_SIZE;
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂu32 const blocks = DIV_ROUND_UP(size,
> DBR_BLOCK_SIZE);
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂu32 mask = ~((~(u32)0) << blocks);
> >
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂdo {
> > @@ -137,7 +137,7 @@ static int alloc_dbr(u16 size)
> > Âstatic void free_dbr(int offs, int size)
> > Â{
> > ÂÂÂÂÂÂÂÂÂint block_idx = offs / DBR_BLOCK_SIZE;
> > -ÂÂÂÂÂÂÂÂu32 const blocks = (size + DBR_BLOCK_SIZE - 1) /
> DBR_BLOCK_SIZE;
> > +ÂÂÂÂÂÂÂÂu32 const blocks = DIV_ROUND_UP(size,
> DBR_BLOCK_SIZE);
> > ÂÂÂÂÂÂÂÂÂu32 mask = ~((~(u32)0) << blocks);
> >
> > ÂÂÂÂÂÂÂÂÂmask <<= block_idx % 32;
> > --
> > 2.7.4
> >
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