2024-04-23 15:22:10

by Nuno Sa via B4 Relay

[permalink] [raw]
Subject: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

From: Nuno Sa <[email protected]>

This is similar to dev_err_probe() but for cases where an ERR_PTR() or
ERR_CAST() is to be returned simplifying patterns like:

dev_err_probe(dev, ret, ...);
return ERR_PTR(ret)
or
dev_err_probe(dev, PTR_ERR(ptr), ...);
return ERR_CAST(ptr)

Signed-off-by: Nuno Sa <[email protected]>
---
include/linux/dev_printk.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
index ae80a303c216..b9623ec22350 100644
--- a/include/linux/dev_printk.h
+++ b/include/linux/dev_printk.h
@@ -277,4 +277,13 @@ do { \

__printf(3, 4) int dev_err_probe(const struct device *dev, int err, const char *fmt, ...);

+/* Simple helper for dev_err_probe() when ERR_PTR() is to be returned. */
+#define dev_err_ptr_probe(dev, ___err, fmt, ...) ({ \
+ ERR_PTR(dev_err_probe(dev, ___err, fmt, ##__VA_ARGS__)); \
+})
+
+/* Simple helper for dev_err_probe() when ERR_CAST() is to be returned. */
+#define dev_err_cast_probe(dev, ___err_ptr, fmt, ...) ({ \
+ ERR_PTR(dev_err_probe(dev, PTR_ERR(___err_ptr), fmt, ##__VA_ARGS__)); \
+})
#endif /* _DEVICE_PRINTK_H_ */

--
2.44.0




2024-04-23 15:40:11

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> From: Nuno Sa <[email protected]>
>
> This is similar to dev_err_probe() but for cases where an ERR_PTR() or
> ERR_CAST() is to be returned simplifying patterns like:
>
> dev_err_probe(dev, ret, ...);
> return ERR_PTR(ret)
> or
> dev_err_probe(dev, PTR_ERR(ptr), ...);
> return ERR_CAST(ptr)

..

> +/* Simple helper for dev_err_probe() when ERR_PTR() is to be returned. */
> +#define dev_err_ptr_probe(dev, ___err, fmt, ...) ({ \
> + ERR_PTR(dev_err_probe(dev, ___err, fmt, ##__VA_ARGS__)); \
> +})

Why ; and hence why ({}) ?

I even believe the compiler may warn if you have double ;; in some cases.

..

> +#define dev_err_cast_probe(dev, ___err_ptr, fmt, ...) ({ \
> + ERR_PTR(dev_err_probe(dev, PTR_ERR(___err_ptr), fmt, ##__VA_ARGS__)); \
> +})

Ditto.

--
With Best Regards,
Andy Shevchenko



2024-04-23 15:54:22

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

On Tue, Apr 23, 2024 at 06:31:20PM +0300, Andy Shevchenko wrote:
> On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> > From: Nuno Sa <[email protected]>

..

> > +#define dev_err_cast_probe(dev, ___err_ptr, fmt, ...) ({ \
> > + ERR_PTR(dev_err_probe(dev, PTR_ERR(___err_ptr), fmt, ##__VA_ARGS__)); \
> > +})

After looking into the next patch I think this should be rewritten to use %pe,
hence should be an exported function. Or dev_err_probe() should be split to
a version that makes the difference between int and const void * (maybe using
_Generic()).

--
With Best Regards,
Andy Shevchenko



2024-05-02 11:34:41

by Nuno Sá

[permalink] [raw]
Subject: Re: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

On Tue, 2024-04-23 at 18:31 +0300, Andy Shevchenko wrote:
> On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> > From: Nuno Sa <[email protected]>
> >
> > This is similar to dev_err_probe() but for cases where an ERR_PTR() or
> > ERR_CAST() is to be returned simplifying patterns like:
> >
> > dev_err_probe(dev, ret, ...);
> > return ERR_PTR(ret)
> > or
> > dev_err_probe(dev, PTR_ERR(ptr), ...);
> > return ERR_CAST(ptr)
>
> ...
>
> > +/* Simple helper for dev_err_probe() when ERR_PTR() is to be returned. */
> > +#define dev_err_ptr_probe(dev, ___err, fmt, ...) ({ \
> > + ERR_PTR(dev_err_probe(dev, ___err, fmt, ##__VA_ARGS__)); \
> > +})
>
> Why ; and hence why ({}) ?
>
> I even believe the compiler may warn if you have double ;; in some cases.
>

Oh yes, no need for any of those...

- Nuno Sá


2024-05-02 11:54:48

by Nuno Sá

[permalink] [raw]
Subject: Re: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

On Tue, 2024-04-23 at 18:45 +0300, Andy Shevchenko wrote:
> On Tue, Apr 23, 2024 at 06:31:20PM +0300, Andy Shevchenko wrote:
> > On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> > > From: Nuno Sa <[email protected]>
>
> ...
>
> > > +#define dev_err_cast_probe(dev, ___err_ptr, fmt,
> > > ...) ({ \
> > > + ERR_PTR(dev_err_probe(dev, PTR_ERR(___err_ptr), fmt,
> > > ##__VA_ARGS__)); \
> > > +})
>
> After looking into the next patch I think this should be rewritten to use %pe,
> hence should be an exported function. Or dev_err_probe() should be split to
> a version that makes the difference between int and const void * (maybe using
> _Generic()).
>

I replied a bit in the other patch but I'm of the opinion that's likely just more
complicated than it needs to be (IMO). Why is the PTR_ERR(___err_ptr) that bad? If we
really want to have a version that takes pointer why not just:

#define dev_err_ptr_probe(dev, ___err, fmt, ...) \
dev_err_probe(dev, PTR_ERR(__err), fmt, ##__VA_ARGS__)


(yes, while _Generic() could be fun I'm trying to avoid it. In this case, I think
having explicit defines is more helpful)

- Nuno Sá

2024-05-02 15:37:34

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v2 1/4] dev_printk: add new dev_err_probe() helpers

On Thu, May 02, 2024 at 01:54:36PM +0200, Nuno S? wrote:
> On Tue, 2024-04-23 at 18:45 +0300, Andy Shevchenko wrote:
> > On Tue, Apr 23, 2024 at 06:31:20PM +0300, Andy Shevchenko wrote:
> > > On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> > > > From: Nuno Sa <[email protected]>

..

> > > > +#define dev_err_cast_probe(dev, ___err_ptr, fmt,
> > > > ...) ({ \
> > > > + ERR_PTR(dev_err_probe(dev, PTR_ERR(___err_ptr), fmt,
> > > > ##__VA_ARGS__)); \
> > > > +})
> >
> > After looking into the next patch I think this should be rewritten to use %pe,
> > hence should be an exported function. Or dev_err_probe() should be split to
> > a version that makes the difference between int and const void * (maybe using
> > _Generic()).
>
> I replied a bit in the other patch but I'm of the opinion that's likely just more
> complicated than it needs to be (IMO). Why is the PTR_ERR(___err_ptr) that bad??If we
> really want to have a version that takes pointer why not just:
>
> #define dev_err_ptr_probe(dev, ___err, fmt, ...) \
> dev_err_probe(dev, PTR_ERR(__err), fmt, ##__VA_ARGS__)
>
>
> (yes, while _Generic() could be fun I'm trying to avoid it. In this case, I think
> having explicit defines is more helpful)

It seems dev_err_probe() already uses %pe, so we are fine.

--
With Best Regards,
Andy Shevchenko