[PATCH] bcache: check return value of register_shrinker

[PATCH] bcache: check return value of register_shrinker

[Michael Lyle]

This is now __must_check, so this kills a warning.  Caller of
bch_btree_cache_alloc in super.c appropriately checks return value
so this is fully plumbed through.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
---
 drivers/md/bcache/btree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 11c5503d31dc..0c2b77e0194b 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -807,7 +807,10 @@ int bch_btree_cache_alloc(struct cache_set *c)
 	c->shrink.scan_objects = bch_mca_scan;
 	c->shrink.seeks = 4;
 	c->shrink.batch = c->btree_pages * 2;
-	register_shrinker(&c->shrink);
+
+	if (register_shrinker(&c->shrink)) {
+		pr_warn("bcache: bch_btree_cache_alloc: could not register shrinker");
+	}
 
 	return 0;
 }
-- 
2.14.1

[PATCH v2] bcache: check return value of register_shrinker

[Michael Lyle]

register_shrinker is now __must_check, so check it to kill a warning.
Caller of bch_btree_cache_alloc in super.c appropriately checks return
value so this is fully plumbed through.

This V2 fixes checkpatch warnings and improves the commit description,
as I was too hasty getting the previous version out.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
---
 drivers/md/bcache/btree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 11c5503d31dc..81e8dc3dbe5e 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -807,7 +807,10 @@ int bch_btree_cache_alloc(struct cache_set *c)
 	c->shrink.scan_objects = bch_mca_scan;
 	c->shrink.seeks = 4;
 	c->shrink.batch = c->btree_pages * 2;
-	register_shrinker(&c->shrink);
+
+	if (register_shrinker(&c->shrink))
+		pr_warn("bcache: %s: could not register shrinker",
+				__func__);
 
 	return 0;
 }
-- 
2.14.1

Re: [PATCH v2] bcache: check return value of register_shrinker

[Michael Lyle]

Just a note to everyone-- a quick Reviewed-by: would be appreciated from
someone here on the bcache list because I'm hoping to get this sent off
with a couple other things to Jens soon.  -mpl

On 11/24/2017 02:02 PM, Michael Lyle wrote:
> register_shrinker is now __must_check, so check it to kill a warning.
> Caller of bch_btree_cache_alloc in super.c appropriately checks return
> value so this is fully plumbed through.
> 
> This V2 fixes checkpatch warnings and improves the commit description,
> as I was too hasty getting the previous version out.
> 
> Signed-off-by: Michael Lyle <mlyle@lyle.org>
> ---
>  drivers/md/bcache/btree.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> index 11c5503d31dc..81e8dc3dbe5e 100644
> --- a/drivers/md/bcache/btree.c
> +++ b/drivers/md/bcache/btree.c
> @@ -807,7 +807,10 @@ int bch_btree_cache_alloc(struct cache_set *c)
>  	c->shrink.scan_objects = bch_mca_scan;
>  	c->shrink.seeks = 4;
>  	c->shrink.batch = c->btree_pages * 2;
> -	register_shrinker(&c->shrink);
> +
> +	if (register_shrinker(&c->shrink))
> +		pr_warn("bcache: %s: could not register shrinker",
> +				__func__);
>  
>  	return 0;
>  }
> 

Re: [PATCH v2] bcache: check return value of register_shrinker

[Vojtech Pavlik]

On Fri, Nov 24, 2017 at 02:24:42PM -0800, Michael Lyle wrote:
> Just a note to everyone-- a quick Reviewed-by: would be appreciated from
> someone here on the bcache list because I'm hoping to get this sent off
> with a couple other things to Jens soon.  -mpl
> 
> On 11/24/2017 02:02 PM, Michael Lyle wrote:
> > register_shrinker is now __must_check, so check it to kill a warning.
> > Caller of bch_btree_cache_alloc in super.c appropriately checks return
> > value so this is fully plumbed through.
> > 
> > This V2 fixes checkpatch warnings and improves the commit description,
> > as I was too hasty getting the previous version out.
> > 
> > Signed-off-by: Michael Lyle <mlyle@lyle.org>
> > ---
> >  drivers/md/bcache/btree.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> > index 11c5503d31dc..81e8dc3dbe5e 100644
> > --- a/drivers/md/bcache/btree.c
> > +++ b/drivers/md/bcache/btree.c
> > @@ -807,7 +807,10 @@ int bch_btree_cache_alloc(struct cache_set *c)
> >  	c->shrink.scan_objects = bch_mca_scan;
> >  	c->shrink.seeks = 4;
> >  	c->shrink.batch = c->btree_pages * 2;
> > -	register_shrinker(&c->shrink);
> > +
> > +	if (register_shrinker(&c->shrink))
> > +		pr_warn("bcache: %s: could not register shrinker",
> > +				__func__);
> >  
> >  	return 0;
> >  }

Reviewed-by: Vojtech Pavlik <vojtech@suse.com>

-- 
Vojtech Pavlik
Director SuSE Labs