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* [PATCH] block: zoned: fix harmless maybe-uninitialized warning
@ 2016-10-21 15:42 Arnd Bergmann
  2016-10-21 20:46 ` Shaun Tancheff
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Arnd Bergmann @ 2016-10-21 15:42 UTC (permalink / raw)
  To: Jens Axboe
  Cc: Arnd Bergmann, Shaun Tancheff, Martin K. Petersen,
	Damien Le Moal, Hannes Reinecke, linux-block, linux-kernel

The blkdev_report_zones produces a harmless warning when
-Wmaybe-uninitialized is set, after gcc gets a little confused
about the multiple 'goto' here:

block/blk-zoned.c: In function 'blkdev_report_zones':
block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Moving the assignment to nr_zones makes this a little simpler
while also avoiding the warning reliably. I'm removing the
extraneous initialization of 'int ret' in the same patch, as
that is semi-related and could cause an uninitialized use of
that variable to not produce a warning.

Fixes: 6a0cb1bc106f ("block: Implement support for zoned block devices")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 block/blk-zoned.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 667f95d86695..472211fa183a 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -80,7 +80,7 @@ int blkdev_report_zones(struct block_device *bdev,
 	unsigned int i, n, nz;
 	unsigned int ofst;
 	void *addr;
-	int ret = 0;
+	int ret;
 
 	if (!q)
 		return -ENXIO;
@@ -179,14 +179,12 @@ int blkdev_report_zones(struct block_device *bdev,
 
 	}
 
+	*nr_zones = nz;
 out:
 	bio_for_each_segment_all(bv, bio, i)
 		__free_page(bv->bv_page);
 	bio_put(bio);
 
-	if (ret == 0)
-		*nr_zones = nz;
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(blkdev_report_zones);
-- 
2.9.0

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH] block: zoned: fix harmless maybe-uninitialized warning
  2016-10-21 15:42 [PATCH] block: zoned: fix harmless maybe-uninitialized warning Arnd Bergmann
@ 2016-10-21 20:46 ` Shaun Tancheff
  2016-10-23 23:38 ` Damien Le Moal
  2016-10-25  1:00 ` Martin K. Petersen
  2 siblings, 0 replies; 5+ messages in thread
From: Shaun Tancheff @ 2016-10-21 20:46 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Jens Axboe, Shaun Tancheff, Martin K. Petersen, Damien Le Moal,
	Hannes Reinecke, linux-block, LKML

On Fri, Oct 21, 2016 at 10:42 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> The blkdev_report_zones produces a harmless warning when
> -Wmaybe-uninitialized is set, after gcc gets a little confused
> about the multiple 'goto' here:
>
> block/blk-zoned.c: In function 'blkdev_report_zones':
> block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this f=
unction [-Werror=3Dmaybe-uninitialized]
>
> Moving the assignment to nr_zones makes this a little simpler
> while also avoiding the warning reliably. I'm removing the
> extraneous initialization of 'int ret' in the same patch, as
> that is semi-related and could cause an uninitialized use of
> that variable to not produce a warning.
>
> Fixes: 6a0cb1bc106f ("block: Implement support for zoned block devices")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  block/blk-zoned.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/block/blk-zoned.c b/block/blk-zoned.c
> index 667f95d86695..472211fa183a 100644
> --- a/block/blk-zoned.c
> +++ b/block/blk-zoned.c
> @@ -80,7 +80,7 @@ int blkdev_report_zones(struct block_device *bdev,
>         unsigned int i, n, nz;
>         unsigned int ofst;
>         void *addr;
> -       int ret =3D 0;
> +       int ret;
>
>         if (!q)
>                 return -ENXIO;
> @@ -179,14 +179,12 @@ int blkdev_report_zones(struct block_device *bdev,
>
>         }
>
> +       *nr_zones =3D nz;
>  out:
>         bio_for_each_segment_all(bv, bio, i)
>                 __free_page(bv->bv_page);
>         bio_put(bio);
>
> -       if (ret =3D=3D 0)
> -               *nr_zones =3D nz;
> -
>         return ret;
>  }
>  EXPORT_SYMBOL_GPL(blkdev_report_zones);
> --
> 2.9.0

Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>

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e=3D



--=20
Shaun Tancheff

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] block: zoned: fix harmless maybe-uninitialized warning
  2016-10-21 15:42 [PATCH] block: zoned: fix harmless maybe-uninitialized warning Arnd Bergmann
  2016-10-21 20:46 ` Shaun Tancheff
@ 2016-10-23 23:38 ` Damien Le Moal
  2016-10-25  1:00 ` Martin K. Petersen
  2 siblings, 0 replies; 5+ messages in thread
From: Damien Le Moal @ 2016-10-23 23:38 UTC (permalink / raw)
  To: Arnd Bergmann, Jens Axboe
  Cc: Shaun Tancheff, Martin K. Petersen, Damien Le Moal,
	Hannes Reinecke, linux-block, linux-kernel


On 10/22/16 00:42, Arnd Bergmann wrote:
> The blkdev_report_zones produces a harmless warning when
> -Wmaybe-uninitialized is set, after gcc gets a little confused
> about the multiple 'goto' here:
> =

> block/blk-zoned.c: In function 'blkdev_report_zones':
> block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this f=
unction [-Werror=3Dmaybe-uninitialized]
> =

> Moving the assignment to nr_zones makes this a little simpler
> while also avoiding the warning reliably. I'm removing the
> extraneous initialization of 'int ret' in the same patch, as
> that is semi-related and could cause an uninitialized use of
> that variable to not produce a warning.
> =

> Fixes: 6a0cb1bc106f ("block: Implement support for zoned block devices")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  block/blk-zoned.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> =

> diff --git a/block/blk-zoned.c b/block/blk-zoned.c
> index 667f95d86695..472211fa183a 100644
> --- a/block/blk-zoned.c
> +++ b/block/blk-zoned.c
> @@ -80,7 +80,7 @@ int blkdev_report_zones(struct block_device *bdev,
>  	unsigned int i, n, nz;
>  	unsigned int ofst;
>  	void *addr;
> -	int ret =3D 0;
> +	int ret;
>  =

>  	if (!q)
>  		return -ENXIO;
> @@ -179,14 +179,12 @@ int blkdev_report_zones(struct block_device *bdev,
>  =

>  	}
>  =

> +	*nr_zones =3D nz;
>  out:
>  	bio_for_each_segment_all(bv, bio, i)
>  		__free_page(bv->bv_page);
>  	bio_put(bio);
>  =

> -	if (ret =3D=3D 0)
> -		*nr_zones =3D nz;
> -
>  	return ret;
>  }
>  EXPORT_SYMBOL_GPL(blkdev_report_zones);

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>

-- =

Damien Le Moal, Ph.D.
Sr. Manager, System Software Research Group,
Western Digital Corporation
Damien.LeMoal@wdc.com
(+81) 0466-98-3593 (ext. 513593)
1 kirihara-cho, Fujisawa,
Kanagawa, 252-0888 Japan
www.wdc.com, www.hgst.com
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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] block: zoned: fix harmless maybe-uninitialized warning
  2016-10-21 15:42 [PATCH] block: zoned: fix harmless maybe-uninitialized warning Arnd Bergmann
  2016-10-21 20:46 ` Shaun Tancheff
  2016-10-23 23:38 ` Damien Le Moal
@ 2016-10-25  1:00 ` Martin K. Petersen
  2016-10-25  2:51   ` Jens Axboe
  2 siblings, 1 reply; 5+ messages in thread
From: Martin K. Petersen @ 2016-10-25  1:00 UTC (permalink / raw)
  To: Arnd Bergmann
  Cc: Jens Axboe, Shaun Tancheff, Martin K. Petersen, Damien Le Moal,
	Hannes Reinecke, linux-block, linux-kernel

>>>>> "Arnd" == Arnd Bergmann <arnd@arndb.de> writes:

Arnd> The blkdev_report_zones produces a harmless warning when
Arnd> -Wmaybe-uninitialized is set, after gcc gets a little confused
Arnd> about the multiple 'goto' here:

Arnd> block/blk-zoned.c: In function 'blkdev_report_zones':
Arnd> block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in
Arnd> this function [-Werror=maybe-uninitialized]

Arnd> Moving the assignment to nr_zones makes this a little simpler
Arnd> while also avoiding the warning reliably. I'm removing the
Arnd> extraneous initialization of 'int ret' in the same patch, as that
Arnd> is semi-related and could cause an uninitialized use of that
Arnd> variable to not produce a warning.

Jens: Are you picking up Arnd's two fixes for the zoned code?

-- 
Martin K. Petersen	Oracle Linux Engineering

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] block: zoned: fix harmless maybe-uninitialized warning
  2016-10-25  1:00 ` Martin K. Petersen
@ 2016-10-25  2:51   ` Jens Axboe
  0 siblings, 0 replies; 5+ messages in thread
From: Jens Axboe @ 2016-10-25  2:51 UTC (permalink / raw)
  To: Martin K. Petersen, Arnd Bergmann
  Cc: Shaun Tancheff, Damien Le Moal, Hannes Reinecke, linux-block,
	linux-kernel

On 10/24/2016 07:00 PM, Martin K. Petersen wrote:
>>>>>> "Arnd" == Arnd Bergmann <arnd@arndb.de> writes:
>
> Arnd> The blkdev_report_zones produces a harmless warning when
> Arnd> -Wmaybe-uninitialized is set, after gcc gets a little confused
> Arnd> about the multiple 'goto' here:
>
> Arnd> block/blk-zoned.c: In function 'blkdev_report_zones':
> Arnd> block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in
> Arnd> this function [-Werror=maybe-uninitialized]
>
> Arnd> Moving the assignment to nr_zones makes this a little simpler
> Arnd> while also avoiding the warning reliably. I'm removing the
> Arnd> extraneous initialization of 'int ret' in the same patch, as that
> Arnd> is semi-related and could cause an uninitialized use of that
> Arnd> variable to not produce a warning.
>
> Jens: Are you picking up Arnd's two fixes for the zoned code?

Yep, adding them now. Thanks Arnd.

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2016-10-25  2:51 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2016-10-21 15:42 [PATCH] block: zoned: fix harmless maybe-uninitialized warning Arnd Bergmann
2016-10-21 20:46 ` Shaun Tancheff
2016-10-23 23:38 ` Damien Le Moal
2016-10-25  1:00 ` Martin K. Petersen
2016-10-25  2:51   ` Jens Axboe

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