diff mbox

mm/sparse.c: fix error path in sparse_add_one_section

Message ID 20180706212327.GA10824@techadventures.net (mailing list archive)
State New, archived
Headers show

Commit Message

Oscar Salvador July 6, 2018, 9:23 p.m. UTC 
On Fri, Jul 06, 2018 at 01:06:58PM -0600, Ross Zwisler wrote:
> The following commit in -next:
> 
> commit 054620849110 ("mm/sparse.c: make sparse_init_one_section void and
> remove check")
> 
> changed how the error handling in sparse_add_one_section() works.
> 
> Previously sparse_index_init() could return -EEXIST, and the function would
> continue on happily.  'ret' would get unconditionally overwritten by the
> result from sparse_init_one_section() and the error code after the 'out:'
> label wouldn't be triggered.

My bad, I missed that.

> diff --git a/mm/sparse.c b/mm/sparse.c
> index 9574113fc745..d254bd2d3289 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -753,8 +753,12 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
>  	 * plus, it does a kmalloc
>  	 */
>  	ret = sparse_index_init(section_nr, pgdat->node_id);
> -	if (ret < 0 && ret != -EEXIST)
> -		return ret;
> +	if (ret < 0) {
> +		if (ret == -EEXIST)
> +			ret = 0;
> +		else
> +			return ret;
> +	}

sparse_index_init() can return:

-ENOMEM, -EEXIST or 0.

So what about this?:

SUSE L3

Comments

Ross Zwisler July 6, 2018, 9:54 p.m. UTC | #1 
On Fri, Jul 06, 2018 at 11:23:27PM +0200, Oscar Salvador wrote:
> On Fri, Jul 06, 2018 at 01:06:58PM -0600, Ross Zwisler wrote:
> > The following commit in -next:
> > 
> > commit 054620849110 ("mm/sparse.c: make sparse_init_one_section void and
> > remove check")
> > 
> > changed how the error handling in sparse_add_one_section() works.
> > 
> > Previously sparse_index_init() could return -EEXIST, and the function would
> > continue on happily.  'ret' would get unconditionally overwritten by the
> > result from sparse_init_one_section() and the error code after the 'out:'
> > label wouldn't be triggered.
> 
> My bad, I missed that.
> 
> > diff --git a/mm/sparse.c b/mm/sparse.c
> > index 9574113fc745..d254bd2d3289 100644
> > --- a/mm/sparse.c
> > +++ b/mm/sparse.c
> > @@ -753,8 +753,12 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
> >  	 * plus, it does a kmalloc
> >  	 */
> >  	ret = sparse_index_init(section_nr, pgdat->node_id);
> > -	if (ret < 0 && ret != -EEXIST)
> > -		return ret;
> > +	if (ret < 0) {
> > +		if (ret == -EEXIST)
> > +			ret = 0;
> > +		else
> > +			return ret;
> > +	}
> 
> sparse_index_init() can return:
> 
> -ENOMEM, -EEXIST or 0.
> 
> So what about this?:
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index f55e79fda03e..eb188eb6b82d 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -770,6 +770,7 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
>         ret = sparse_index_init(section_nr, pgdat->node_id);
>         if (ret < 0 && ret != -EEXIST)
>                 return ret;
> +       ret = 0;
> 
> Does this look more clean?

Sure, that's probably better.

Andrew, what's the easiest way forward?  I can send out a v2, you can fold
this into his previous patch, or something else?
Andrew Morton July 6, 2018, 9:58 p.m. UTC | #2 
On Fri, 6 Jul 2018 15:54:37 -0600 Ross Zwisler <ross.zwisler@linux.intel.com> wrote:

> On Fri, Jul 06, 2018 at 11:23:27PM +0200, Oscar Salvador wrote:
> > On Fri, Jul 06, 2018 at 01:06:58PM -0600, Ross Zwisler wrote:
> > > The following commit in -next:
> > > 
> > > commit 054620849110 ("mm/sparse.c: make sparse_init_one_section void and
> > > remove check")
> > > 
> > > changed how the error handling in sparse_add_one_section() works.
> > > 
> > > Previously sparse_index_init() could return -EEXIST, and the function would
> > > continue on happily.  'ret' would get unconditionally overwritten by the
> > > result from sparse_init_one_section() and the error code after the 'out:'
> > > label wouldn't be triggered.
> > 
> > My bad, I missed that.
> > 
> > > diff --git a/mm/sparse.c b/mm/sparse.c
> > > index 9574113fc745..d254bd2d3289 100644
> > > --- a/mm/sparse.c
> > > +++ b/mm/sparse.c
> > > @@ -753,8 +753,12 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
> > >  	 * plus, it does a kmalloc
> > >  	 */
> > >  	ret = sparse_index_init(section_nr, pgdat->node_id);
> > > -	if (ret < 0 && ret != -EEXIST)
> > > -		return ret;
> > > +	if (ret < 0) {
> > > +		if (ret == -EEXIST)
> > > +			ret = 0;
> > > +		else
> > > +			return ret;
> > > +	}
> > 
> > sparse_index_init() can return:
> > 
> > -ENOMEM, -EEXIST or 0.
> > 
> > So what about this?:
> > 
> > diff --git a/mm/sparse.c b/mm/sparse.c
> > index f55e79fda03e..eb188eb6b82d 100644
> > --- a/mm/sparse.c
> > +++ b/mm/sparse.c
> > @@ -770,6 +770,7 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
> >         ret = sparse_index_init(section_nr, pgdat->node_id);
> >         if (ret < 0 && ret != -EEXIST)
> >                 return ret;
> > +       ret = 0;
> > 
> > Does this look more clean?
> 
> Sure, that's probably better.
> 
> Andrew, what's the easiest way forward?  I can send out a v2, you can fold
> this into his previous patch, or something else?

Whatever ;)  v2 works.
diff mbox

Patch

diff --git a/mm/sparse.c b/mm/sparse.c
index f55e79fda03e..eb188eb6b82d 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -770,6 +770,7 @@  int __meminit sparse_add_one_section(struct pglist_data *pgdat,
        ret = sparse_index_init(section_nr, pgdat->node_id);
        if (ret < 0 && ret != -EEXIST)
                return ret;
+       ret = 0;

Does this look more clean?
-- 
Oscar Salvador