blk_stack_limits() contains:
	t->zoned = max(t->zoned, b->zoned);
These are bool, so it is just a bitwise or.
However it generates:
error: comparison of constant ‘0’ with boolean expression is always true [-Werror=bool-compare]
inside the signedness check that max() does unless a '+ 0' is added.
It is a shame the compiler generates this warning for code that will
be optimised away.

Change so that the extra '+ 0' can be removed.

Signed-off-by: David Laight <david.laight@aculab.com>
---
 block/blk-settings.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 06ea91e51b8b..9ca21fea039d 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -688,7 +688,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 						   b->max_secure_erase_sectors);
 	t->zone_write_granularity = max(t->zone_write_granularity,
 					b->zone_write_granularity);
-	t->zoned = max(t->zoned, b->zoned);
+	t->zoned = t->zoned | b->zoned;
 	return ret;
 }
 EXPORT_SYMBOL(blk_stack_limits);
-- 
2.17.1

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

On Sun, 28 Jan 2024, David Laight <David.Laight@ACULAB.COM> wrote:
> blk_stack_limits() contains:
> 	t->zoned = max(t->zoned, b->zoned);
> These are bool, so it is just a bitwise or.

Should be a logical or, really. And || in code.

BR,
Jani.


> However it generates:
> error: comparison of constant ‘0’ with boolean expression is always true [-Werror=bool-compare]
> inside the signedness check that max() does unless a '+ 0' is added.
> It is a shame the compiler generates this warning for code that will
> be optimised away.
>
> Change so that the extra '+ 0' can be removed.
>
> Signed-off-by: David Laight <david.laight@aculab.com>
> ---
>  block/blk-settings.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 06ea91e51b8b..9ca21fea039d 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -688,7 +688,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
>  						   b->max_secure_erase_sectors);
>  	t->zone_write_granularity = max(t->zone_write_granularity,
>  					b->zone_write_granularity);
> -	t->zoned = max(t->zoned, b->zoned);
> +	t->zoned = t->zoned | b->zoned;
>  	return ret;
>  }
>  EXPORT_SYMBOL(blk_stack_limits);

-- 
Jani Nikula, Intel

From: Jani Nikula
> Sent: 29 January 2024 09:08
> 
> On Sun, 28 Jan 2024, David Laight <David.Laight@ACULAB.COM> wrote:
> > blk_stack_limits() contains:
> > 	t->zoned = max(t->zoned, b->zoned);
> > These are bool, so it is just a bitwise or.
> 
> Should be a logical or, really. And || in code.

Not really, bitwise is fine for bool (especially for 'or')
and generates better code.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

On Mon, Jan 29, 2024 at 09:22:40AM +0000, David Laight wrote:
> From: Jani Nikula
> > Sent: 29 January 2024 09:08
> > 
> > On Sun, 28 Jan 2024, David Laight <David.Laight@ACULAB.COM> wrote:
> > > blk_stack_limits() contains:
> > > 	t->zoned = max(t->zoned, b->zoned);
> > > These are bool, so it is just a bitwise or.
> > 
> > Should be a logical or, really. And || in code.
> 
> Not really, bitwise is fine for bool (especially for 'or')
> and generates better code.

For | vs || the type doesn't make a difference...  It makes a difference
for AND.  "0x1 & 0x10" vs "0x1 && 0x10".

regards,
dan carpenter

On Mon, 29 Jan 2024, David Laight <David.Laight@ACULAB.COM> wrote:
> From: Jani Nikula
>> Sent: 29 January 2024 09:08
>> 
>> On Sun, 28 Jan 2024, David Laight <David.Laight@ACULAB.COM> wrote:
>> > blk_stack_limits() contains:
>> > 	t->zoned = max(t->zoned, b->zoned);
>> > These are bool, so it is just a bitwise or.
>> 
>> Should be a logical or, really. And || in code.
>
> Not really, bitwise is fine for bool (especially for 'or')
> and generates better code.

Logical operations for booleans are more readable for humans than
bitwise. And semantically correct.

With a = b || c you know what happens regardless of the types in
question. a = b | c you have to look up the types to know what's going
on.

To me, better code only matters if it's a hotpath.

That said, not my are of maintenance, so *shrug*.


BR,
Jani.


-- 
Jani Nikula, Intel

On Sun, 28 Jan 2024 at 11:36, David Laight <David.Laight@aculab.com> wrote:
>
> However it generates:
> error: comparison of constant ‘0’ with boolean expression is always true [-Werror=bool-compare]
> inside the signedness check that max() does unless a '+ 0' is added.

Please fix your locale. You have random garbage characters there,
presumably because you have some incorrect locale setting somewhere in
your toolchain.

           Linus

From: Linus Torvalds
> Sent: 28 January 2024 19:59
> 
> On Sun, 28 Jan 2024 at 11:36, David Laight <David.Laight@aculab.com> wrote:
> >
> > However it generates:
> > error: comparison of constant ‘0’ with boolean expression is always true [-Werror=bool-compare]
> > inside the signedness check that max() does unless a '+ 0' is added.
> 
> Please fix your locale. You have random garbage characters there,
> presumably because you have some incorrect locale setting somewhere in
> your toolchain.

Hmmmm blame gcc :-)
The error message displays as '0' but is e2:80:98 30 e2:80:99
I HATE UTF-8, it wouldn't be as bad if it were a bijection.

Lets see if adding 'LANG=C' in the shell script I use to
do kernel builds is enough.

I also managed to send parts 1 to 6 without deleting the RE:
(I have to cut&paste from wordpad into a 'reply-all' of the first
message I send. Work uses mimecast and it has started bouncing
my copy of every message I send to the lists.)

Maybe I should start using telnet to send raw SMTP :-)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

On Sun, 28 Jan 2024 at 14:22, David Laight <David.Laight@aculab.com> wrote:
>
> Hmmmm blame gcc :-)

I do agree that the gcc warning quoting is unnecessarily ugly (even
just visually), but..

> The error message displays as '0' but is e2:80:98 30 e2:80:99
> I HATE UTF-8, it wouldn't be as bad if it were a bijection.

No, that's not the problem. The UTF-8 that gcc emits is fine.

And your email was also UTF-8:

    Content-Type: text/plain; charset=UTF-8

The problem is that you clearly then used some other tool in between
that took the UTF-8 byte stream, and used it as (presumably) Latin1,
which is bogus.

If you just make everything use and stay as UTF-8, it all works out
beautifully. But I suspect you have an editor or a MUA that is fixed
in some 1980s mindset, and when you cut-and-pasted the UTF-8, it
treated it as Latin1.

Just make all your environment be utf-8, like it should be. It's not
the 80s any more. We don't do mullets, and we don't do Latin1, ok?

            Linus