Re: [PATCH v2] blkcg: add sanity check for blkcg policy operations

2017-10-11 Thread weiping zhang 
On Wed, Oct 11, 2017 at 10:51:32AM -0600, Jens Axboe wrote:
> On 10/11/2017 03:46 AM, weiping zhang wrote:
> > blkcg policy should keep cpd/pd's alloc_fn and free_fn in pairs,
> > otherwise policy would register fail.
> > 
> > Signed-off-by: weiping zhang 
> > ---
> >  block/blk-cgroup.c | 10 ++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> > index e7ec676..67b01c5 100644
> > --- a/block/blk-cgroup.c
> > +++ b/block/blk-cgroup.c
> > @@ -1419,6 +1419,16 @@ int blkcg_policy_register(struct blkcg_policy *pol)
> > if (i >= BLKCG_MAX_POLS)
> > goto err_unlock;
> >  
> > +   /* Make sure cpd_alloc_fn and cpd_free_fn in pairs */
> > +   if ((pol->cpd_alloc_fn && !pol->cpd_free_fn) ||
> > +   (!pol->cpd_alloc_fn && pol->cpd_free_fn))
> > +   goto err_unlock;
> 
> This might be cleaner (and more readable) as:
> 
> if (!pol->cpd_alloc_fn ^ !pol->cpd_free_fn)
> goto err_unlock;
> 
> Ditto for the pd part.
> 
Really nice, I'll send v3.

Thanks

Re: [PATCH v2] blkcg: add sanity check for blkcg policy operations

2017-10-11 Thread Jens Axboe 
On 10/11/2017 03:46 AM, weiping zhang wrote:
> blkcg policy should keep cpd/pd's alloc_fn and free_fn in pairs,
> otherwise policy would register fail.
> 
> Signed-off-by: weiping zhang 
> ---
>  block/blk-cgroup.c | 10 ++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index e7ec676..67b01c5 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -1419,6 +1419,16 @@ int blkcg_policy_register(struct blkcg_policy *pol)
>   if (i >= BLKCG_MAX_POLS)
>   goto err_unlock;
>  
> + /* Make sure cpd_alloc_fn and cpd_free_fn in pairs */
> + if ((pol->cpd_alloc_fn && !pol->cpd_free_fn) ||
> + (!pol->cpd_alloc_fn && pol->cpd_free_fn))
> + goto err_unlock;

This might be cleaner (and more readable) as:

if (!pol->cpd_alloc_fn ^ !pol->cpd_free_fn)
goto err_unlock;

Ditto for the pd part.

-- 
Jens Axboe

[PATCH v2] blkcg: add sanity check for blkcg policy operations

2017-10-11 Thread weiping zhang 
blkcg policy should keep cpd/pd's alloc_fn and free_fn in pairs,
otherwise policy would register fail.

Signed-off-by: weiping zhang 
---
 block/blk-cgroup.c | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e7ec676..67b01c5 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1419,6 +1419,16 @@ int blkcg_policy_register(struct blkcg_policy *pol)
if (i >= BLKCG_MAX_POLS)
goto err_unlock;
 
+   /* Make sure cpd_alloc_fn and cpd_free_fn in pairs */
+   if ((pol->cpd_alloc_fn && !pol->cpd_free_fn) ||
+   (!pol->cpd_alloc_fn && pol->cpd_free_fn))
+   goto err_unlock;
+
+   /* Make sure pd_alloc_fn and pd_free_fn in pairs */
+   if ((pol->pd_alloc_fn && !pol->pd_free_fn) ||
+   (!pol->pd_alloc_fn && pol->pd_free_fn))
+   goto err_unlock;
+
/* register @pol */
pol->plid = i;
blkcg_policy[pol->plid] = pol;
-- 
2.9.4