[4.9.1] Compiler warnings in bcache

[4.9.1] Compiler warnings in bcache

[Kai Krakow]

When compiling kernel 4.9.1, I'm seeing the following warnings:

In file included from ./include/linux/bio.h:23:0,
                 from drivers/md/bcache/bcache.h:181,
                 from drivers/md/bcache/writeback.c:9:
drivers/md/bcache/writeback.c: In Funktion »bch_cached_dev_writeback_init«:
./include/linux/ioprio.h:15:73: Warnung: Klammern um Arithmetik in Operand von »|« empfohlen [-Wparentheses]
 #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
                                                                         ^
drivers/md/bcache/writeback.c:515:25: Anmerkung: bei Substitution des Makros »IOPRIO_PRIO_VALUE«
  dc->ioprio_bypass    = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NR-1);
                         ^

It suggests to put parentheses around the expression with the "|"
operand. No other kernel source files show warnings for me, so maybe it
should be fixed.

I would create a patch myself but I'm not sure if it would be correct
and sufficient to put parenthesis around "data" like this:

#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | (data))

-- 
Regards,
Kai

Replies to list-only preferred.

Re: [4.9.1] Compiler warnings in bcache

[Coly Li]

On 2017/1/10 上午2:34, Kai Krakow wrote:
> When compiling kernel 4.9.1, I'm seeing the following warnings:
> 
> In file included from ./include/linux/bio.h:23:0,
>                  from drivers/md/bcache/bcache.h:181,
>                  from drivers/md/bcache/writeback.c:9:
> drivers/md/bcache/writeback.c: In Funktion »bch_cached_dev_writeback_init«:
> ./include/linux/ioprio.h:15:73: Warnung: Klammern um Arithmetik in Operand von »|« empfohlen [-Wparentheses]
>  #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
>                                                                          ^
> drivers/md/bcache/writeback.c:515:25: Anmerkung: bei Substitution des Makros »IOPRIO_PRIO_VALUE«
>   dc->ioprio_bypass    = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NR-1);
>                          ^
> 
> It suggests to put parentheses around the expression with the "|"
> operand. No other kernel source files show warnings for me, so maybe it
> should be fixed.
> 
> I would create a patch myself but I'm not sure if it would be correct
> and sufficient to put parenthesis around "data" like this:
> 
> #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | (data))
> 

Hi Kai Krakow,

This fix is necessary, please send a patch to IOPRIO_PRIO_VALUE().

BTW, I don't see dc->ioprio_bypass from upstream kernel source, is it
from a development tree ?


-- 
Coly Li

Re: [4.9.1] Compiler warnings in bcache

[Kai Krakow]

Am Tue, 10 Jan 2017 13:41:25 +0800
schrieb Coly Li <i@coly.li>:

> On 2017/1/10 上午2:34, Kai Krakow wrote:
> > When compiling kernel 4.9.1, I'm seeing the following warnings:
> > 
> > In file included from ./include/linux/bio.h:23:0,
> >                  from drivers/md/bcache/bcache.h:181,
> >                  from drivers/md/bcache/writeback.c:9:
> > drivers/md/bcache/writeback.c: In Funktion
> > »bch_cached_dev_writeback_init«: ./include/linux/ioprio.h:15:73:
> > Warnung: Klammern um Arithmetik in Operand von »|« empfohlen
> > [-Wparentheses] #define IOPRIO_PRIO_VALUE(class, data) (((class) <<
> > IOPRIO_CLASS_SHIFT) | data) ^ drivers/md/bcache/writeback.c:515:25:
> > Anmerkung: bei Substitution des Makros »IOPRIO_PRIO_VALUE«
> > dc->ioprio_bypass    = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
> > IOPRIO_BE_NR-1); ^
> > 
> > It suggests to put parentheses around the expression with the "|"
> > operand. No other kernel source files show warnings for me, so
> > maybe it should be fixed.
> > 
> > I would create a patch myself but I'm not sure if it would be
> > correct and sufficient to put parenthesis around "data" like this:
> > 
> > #define IOPRIO_PRIO_VALUE(class, data) (((class) <<
> > IOPRIO_CLASS_SHIFT) | (data)) 
> 
> Hi Kai Krakow,
> 
> This fix is necessary, please send a patch to IOPRIO_PRIO_VALUE().
> 
> BTW, I don't see dc->ioprio_bypass from upstream kernel source, is it
> from a development tree ?

Ahhh... This is from Erics ioprio bypass patches. I'm still using the
4.8 patchset with 4.9. Maybe it has been updated meanwhile?

-- 
Regards,
Kai

Replies to list-only preferred.

Re: [4.9.1] Compiler warnings in bcache

[Coly Li]

On 2017/1/11 上午4:51, Kai Krakow wrote:
> Am Tue, 10 Jan 2017 13:41:25 +0800
> schrieb Coly Li <i@coly.li>:
> 
>> On 2017/1/10 上午2:34, Kai Krakow wrote:
>>> When compiling kernel 4.9.1, I'm seeing the following warnings:
>>>
>>> In file included from ./include/linux/bio.h:23:0,
>>>                  from drivers/md/bcache/bcache.h:181,
>>>                  from drivers/md/bcache/writeback.c:9:
>>> drivers/md/bcache/writeback.c: In Funktion
>>> »bch_cached_dev_writeback_init«: ./include/linux/ioprio.h:15:73:
>>> Warnung: Klammern um Arithmetik in Operand von »|« empfohlen
>>> [-Wparentheses] #define IOPRIO_PRIO_VALUE(class, data) (((class) <<
>>> IOPRIO_CLASS_SHIFT) | data) ^ drivers/md/bcache/writeback.c:515:25:
>>> Anmerkung: bei Substitution des Makros »IOPRIO_PRIO_VALUE«
>>> dc->ioprio_bypass    = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE,
>>> IOPRIO_BE_NR-1); ^
>>>
>>> It suggests to put parentheses around the expression with the "|"
>>> operand. No other kernel source files show warnings for me, so
>>> maybe it should be fixed.
>>>
>>> I would create a patch myself but I'm not sure if it would be
>>> correct and sufficient to put parenthesis around "data" like this:
>>>
>>> #define IOPRIO_PRIO_VALUE(class, data) (((class) <<
>>> IOPRIO_CLASS_SHIFT) | (data)) 
>>
>> Hi Kai Krakow,
>>
>> This fix is necessary, please send a patch to IOPRIO_PRIO_VALUE().
>>
>> BTW, I don't see dc->ioprio_bypass from upstream kernel source, is it
>> from a development tree ?
> 
> Ahhh... This is from Erics ioprio bypass patches. I'm still using the
> 4.8 patchset with 4.9. Maybe it has been updated meanwhile?
> 

Understand. Please compose a patch for this fix, thank you in advance :-)

-- 
Coly Li

IOPRIO_PRIO_VALUE needs parens around (data) (was: [4.9.1] Compiler warnings in bcache)

[Eric Wheeler]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1913 bytes --]

On Tue, 10 Jan 2017, Coly Li wrote:
> On 2017/1/10 上午2:34, Kai Krakow wrote:
> > When compiling kernel 4.9.1, I'm seeing the following warnings:
> > 
> > In file included from ./include/linux/bio.h:23:0,
> >                  from drivers/md/bcache/bcache.h:181,
> >                  from drivers/md/bcache/writeback.c:9:
> > drivers/md/bcache/writeback.c: In Funktion »bch_cached_dev_writeback_init«:
> > ./include/linux/ioprio.h:15:73: Warnung: Klammern um Arithmetik in Operand von »|« empfohlen [-Wparentheses]
> >  #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
> >                                                                          ^
> > drivers/md/bcache/writeback.c:515:25: Anmerkung: bei Substitution des Makros »IOPRIO_PRIO_VALUE«
> >   dc->ioprio_bypass    = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NR-1);
> >                          ^
> > 
> > It suggests to put parentheses around the expression with the "|"
> > operand. No other kernel source files show warnings for me, so maybe it
> > should be fixed.
> > 
> > I would create a patch myself but I'm not sure if it would be correct
> > and sufficient to put parenthesis around "data" like this:
> > 
> > #define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | (data))

I caught that before submitting to Jens, so its in 4.10.  I agree with 
Coly, however, that (data) should be added but I'm unable to do that at 
the moment.


--
Eric Wheeler



> > 
> 
> Hi Kai Krakow,
> 
> This fix is necessary, please send a patch to IOPRIO_PRIO_VALUE().
> 
> BTW, I don't see dc->ioprio_bypass from upstream kernel source, is it
> from a development tree ?
> 
> 
> -- 
> Coly Li
> --
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