From: Nuno Sa <nuno.sa@analog.com>

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 <nuno.sa@analog.com>
---
 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

On Tue, Apr 23, 2024 at 05:20:30PM +0200, Nuno Sa via B4 Relay wrote:
> From: Nuno Sa <nuno.sa@analog.com>
> 
> 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

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 <nuno.sa@analog.com>
> > 
> > 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

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 <nuno.sa@analog.com>

...

> > +#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

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 <nuno.sa@analog.com>
> 
> ...
> 
> > > +#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

On Thu, May 02, 2024 at 01:54:36PM +0200, Nuno Sá 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 <nuno.sa@analog.com>

...

> > > > +#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