[PATCH] lib/vsprintf: replace min_t/max_t with min/max

[PATCH] lib/vsprintf: replace min_t/max_t with min/max

[Thorsten Blum]

Use the simpler min()/max() macros since the values are all compatible.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 lib/vsprintf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 9f359b31c8d1..57ae85680536 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1208,7 +1208,7 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
 	}
 
 	if (spec.field_width > 0)
-		len = min_t(int, spec.field_width, 64);
+		len = min(spec.field_width, 64);
 
 	for (i = 0; i < len; ++i) {
 		if (buf < end)
@@ -1233,7 +1233,7 @@ char *bitmap_string(char *buf, char *end, const unsigned long *bitmap,
 		    struct printf_spec spec, const char *fmt)
 {
 	const int CHUNKSZ = 32;
-	int nr_bits = max_t(int, spec.field_width, 0);
+	int nr_bits = max(spec.field_width, 0);
 	int i, chunksz;
 	bool first = true;
 
@@ -1276,7 +1276,7 @@ static noinline_for_stack
 char *bitmap_list_string(char *buf, char *end, const unsigned long *bitmap,
 			 struct printf_spec spec, const char *fmt)
 {
-	int nr_bits = max_t(int, spec.field_width, 0);
+	int nr_bits = max(spec.field_width, 0);
 	bool first = true;
 	int rbot, rtop;
 

Re: [PATCH] lib/vsprintf: replace min_t/max_t with min/max

[Petr Mladek]

On Mon 2026-05-18 14:31:47, Thorsten Blum wrote:
> Use the simpler min()/max() macros since the values are all compatible.
> 
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1208,7 +1208,7 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
>  	}
>  
>  	if (spec.field_width > 0)
> -		len = min_t(int, spec.field_width, 64);
> +		len = min(spec.field_width, 64);

Honestly, I do not see any big advantage in replacing the macros.
In fact, the min()/max() macros are even more complex because
they check compatibility of the compared types.

IMHO, this adds non-necessary churn into the git history without
an obvious advantage.

Best Regards,
Petr

Re: [PATCH] lib/vsprintf: replace min_t/max_t with min/max

[Andy Shevchenko]

On Thu, May 21, 2026 at 03:49:12PM +0200, Petr Mladek wrote:
> On Mon 2026-05-18 14:31:47, Thorsten Blum wrote:
> > Use the simpler min()/max() macros since the values are all compatible.

...

> >  	if (spec.field_width > 0)
> > -		len = min_t(int, spec.field_width, 64);
> > +		len = min(spec.field_width, 64);
> 
> Honestly, I do not see any big advantage in replacing the macros.
> In fact, the min()/max() macros are even more complex because
> they check compatibility of the compared types.
> 
> IMHO, this adds non-necessary churn into the git history without
> an obvious advantage.

The advantage I see is to give a good example to others to avoid min_t()
whenever is possible. I am not insisting to include this patch, just
share my 2 cents.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] lib/vsprintf: replace min_t/max_t with min/max

[David Laight]

On Thu, 21 May 2026 15:49:12 +0200
Petr Mladek <pmladek@suse.com> wrote:

> On Mon 2026-05-18 14:31:47, Thorsten Blum wrote:
> > Use the simpler min()/max() macros since the values are all compatible.
> > 
> > --- a/lib/vsprintf.c
> > +++ b/lib/vsprintf.c
> > @@ -1208,7 +1208,7 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
> >  	}
> >  
> >  	if (spec.field_width > 0)
> > -		len = min_t(int, spec.field_width, 64);
> > +		len = min(spec.field_width, 64);  
> 
> Honestly, I do not see any big advantage in replacing the macros.
> In fact, the min()/max() macros are even more complex because
> they check compatibility of the compared types.

But min_t() is often worse that just letting the compiler promote
a negative signed value to a very large unsigned one.

There are basically three common misuses:
1) Using the type you want the result to be.
2) Using the smaller type, including 'long' v 'u64' on 32bit.
3) Thinking min_t(type, a, b) is the best way to compare items of
   type 'type'.

All not helped by checkpatch suggesting that:
	min(foo, (type)bar)
is 'an opportunity for':
	min_t(type, foo, bar)
but the latter is:
	min((type)foo, (type)bar)
and you never need both casts.

There are also a few of the pointless/buggy:
	min_t(u8, foo, U8_MAX)
but you'd notice that the test:
	if ((u8)foo > U8_MAX)
doesn't do what was intended.

Ideally min_t() ought to be killed, but it is a big job.
(The sort of thing Linus could because of his 'god' bit.)

-- David

> 
> IMHO, this adds non-necessary churn into the git history without
> an obvious advantage.
> 
> Best Regards,
> Petr
> 

Re: [PATCH] lib/vsprintf: replace min_t/max_t with min/max

[Petr Mladek]

On Wed 2026-06-03 10:35:39, David Laight wrote:
> On Thu, 21 May 2026 15:49:12 +0200
> Petr Mladek <pmladek@suse.com> wrote:
> 
> > On Mon 2026-05-18 14:31:47, Thorsten Blum wrote:
> > > Use the simpler min()/max() macros since the values are all compatible.
> > > 
> > > --- a/lib/vsprintf.c
> > > +++ b/lib/vsprintf.c
> > > @@ -1208,7 +1208,7 @@ char *hex_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
> > >  	}
> > >  
> > >  	if (spec.field_width > 0)
> > > -		len = min_t(int, spec.field_width, 64);
> > > +		len = min(spec.field_width, 64);  
> > 
> > Honestly, I do not see any big advantage in replacing the macros.
> > In fact, the min()/max() macros are even more complex because
> > they check compatibility of the compared types.
> 
> But min_t() is often worse that just letting the compiler promote
> a negative signed value to a very large unsigned one.
> 
> There are basically three common misuses:
> 1) Using the type you want the result to be.
> 2) Using the smaller type, including 'long' v 'u64' on 32bit.
> 3) Thinking min_t(type, a, b) is the best way to compare items of
>    type 'type'.
> 
> All not helped by checkpatch suggesting that:
> 	min(foo, (type)bar)
> is 'an opportunity for':
> 	min_t(type, foo, bar)
> but the latter is:
> 	min((type)foo, (type)bar)
> and you never need both casts.
> 
> There are also a few of the pointless/buggy:
> 	min_t(u8, foo, U8_MAX)
> but you'd notice that the test:
> 	if ((u8)foo > U8_MAX)
> doesn't do what was intended.
> 
> Ideally min_t() ought to be killed, but it is a big job.
> (The sort of thing Linus could because of his 'god' bit.)

Andy, David, thanks for feedback. Fair enough.
Thorsten, thanks for the patch.

I have just pushed the patch into printk/linux.git,
branch for-7.2.

Best Regards,
Petr

Re: [PATCH] lib/vsprintf: replace min_t/max_t with min/max

[Alexey Dobriyan]

Andy Shevchenko wrote:

> > >  	if (spec.field_width > 0)
> > > -		len = min_t(int, spec.field_width, 64);
> > > +		len = min(spec.field_width, 64);
> >
> > Honestly, I do not see any big advantage in replacing the macros.
> > In fact, the min()/max() macros are even more complex because
> > they check compatibility of the compared types.
> >
> > IMHO, this adds non-necessary churn into the git history without
> > an obvious advantage.
> 
> The advantage I see is to give a good example to others to avoid min_t()
> whenever is possible. I am not insisting to include this patch, just
> share my 2 cents.

Patch is good. "field_width" was bitfield for a long time, so min/max
couldn't be used.

	%alexey