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From: Kai Krakow <hurikhan77@gmail.com>
To: linux-bcache@vger.kernel.org
Subject: [4.9.1] Compiler warnings in bcache
Date: Mon, 9 Jan 2017 19:34:22 +0100	[thread overview]
Message-ID: <20170109193422.734b3088@jupiter.sol.kaishome.de> (raw)

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.

             reply	other threads:[~2017-01-09 18:34 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-09 18:34 Kai Krakow [this message]
2017-01-10  5:41 ` [4.9.1] Compiler warnings in bcache Coly Li
2017-01-10 20:51   ` Kai Krakow
2017-01-15  9:36     ` Coly Li
2017-01-31 19:01   ` IOPRIO_PRIO_VALUE needs parens around (data) (was: [4.9.1] Compiler warnings in bcache) Eric Wheeler

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