Re: [PATCH v3 02/19] coccinelle: misc: Add secs_to_jiffies script

[Julia Lawall <julia.lawall@xxxxxxxx>]

On Tue, 17 Dec 2024, Alexander Gordeev wrote:

> On Tue, Dec 10, 2024 at 10:02:33PM +0000, Easwar Hariharan wrote:
>
> Hi Easwar,
>
> > This script finds and suggests conversions of timeout patterns that
> > result in seconds-denominated timeouts to use the new secs_to_jiffies()
> > API in include/linux/jiffies.h for better readability.
> >
> > Suggested-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
> > Signed-off-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx>
> > ---
> >  scripts/coccinelle/misc/secs_to_jiffies.cocci | 22 ++++++++++++++++++++++
> >  1 file changed, 22 insertions(+)
> >
> > diff --git a/scripts/coccinelle/misc/secs_to_jiffies.cocci b/scripts/coccinelle/misc/secs_to_jiffies.cocci
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..8bbb2884ea5db939c63fd4513cf5ca8c977aa8cb
> > --- /dev/null
> > +++ b/scripts/coccinelle/misc/secs_to_jiffies.cocci
> > @@ -0,0 +1,22 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +///
> > +/// Find usages of:
> > +/// - msecs_to_jiffies(value*1000)
> > +/// - msecs_to_jiffies(value*MSEC_PER_SEC)
> > +///
> > +// Confidence: High
> > +// Copyright: (C) 2024 Easwar Hariharan, Microsoft
> > +// Keywords: secs, seconds, jiffies
> > +//
> > +
> > +virtual patch
> > +
> > +@depends on patch@ constant C; @@
> > +
> > +- msecs_to_jiffies(C * 1000)
> > ++ secs_to_jiffies(C)
> > +
> > +@depends on patch@ constant C; @@
> > +
> > +- msecs_to_jiffies(C * MSEC_PER_SEC)
> > ++ secs_to_jiffies(C)
>
> If you used this script only, then it did not seem to recognize line arch/s390/mm/cmm.c:207
>
> 	mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC));

There is the requirement that C is a constant, and cmm_timeout_seconds is
not considered to be a constant, ie it is not all capital letters.
Indeed, it doesn't seem to be a constant at all.  I don't know if the
requirement of being a comstant is really necessary.

julia

>
> Thanks!
>