[v1] net: xen-netback: hash.c: Use built-in RCU list checking

[Xen-devel] [PATCH] net: xen-netback: hash.c: Use built-in RCU list checking

Posted by madhuparnabhowmik04@gmail.com 6 years ago

From: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>

list_for_each_entry_rcu has built-in RCU and lock checking.
Pass cond argument to list_for_each_entry_rcu.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
---
 drivers/net/xen-netback/hash.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
index 10d580c3dea3..3f9783f70a75 100644
--- a/drivers/net/xen-netback/hash.c
+++ b/drivers/net/xen-netback/hash.c
@@ -51,7 +51,8 @@ static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,
 
 	found = false;
 	oldest = NULL;
-	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
+	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
+				lockdep_is_held(&vif->hash.cache.lock)) {
 		/* Make sure we don't add duplicate entries */
 		if (entry->len == len &&
 		    memcmp(entry->tag, tag, len) == 0)
-- 
2.17.1


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Re: [Xen-devel] [PATCH] net: xen-netback: hash.c: Use built-in RCU list checking

Posted by Wei Liu 6 years ago

On Wed, Jan 15, 2020 at 07:48:40PM +0530, madhuparnabhowmik04@gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
> 
> list_for_each_entry_rcu has built-in RCU and lock checking.
> Pass cond argument to list_for_each_entry_rcu.
> 
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>

You seem to have dropped the second hunk which modified
xenvif_flush_hash, is that a mistake?

Wei.

> ---
>  drivers/net/xen-netback/hash.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
> index 10d580c3dea3..3f9783f70a75 100644
> --- a/drivers/net/xen-netback/hash.c
> +++ b/drivers/net/xen-netback/hash.c
> @@ -51,7 +51,8 @@ static void xenvif_add_hash(struct xenvif *vif, const u8 *tag,
>  
>  	found = false;
>  	oldest = NULL;
> -	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
> +	list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
> +				lockdep_is_held(&vif->hash.cache.lock)) {
>  		/* Make sure we don't add duplicate entries */
>  		if (entry->len == len &&
>  		    memcmp(entry->tag, tag, len) == 0)
> -- 
> 2.17.1
> 

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Re: [Xen-devel] [PATCH] net: xen-netback: hash.c: Use built-in RCU list checking

Posted by Madhuparna Bhowmik 6 years ago

On Wed, Jan 15, 2020 at 8:35 PM Wei Liu <wei.liu@kernel.org> wrote:

> On Wed, Jan 15, 2020 at 07:48:40PM +0530, madhuparnabhowmik04@gmail.com
> wrote:
> > From: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
> >
> > list_for_each_entry_rcu has built-in RCU and lock checking.
> > Pass cond argument to list_for_each_entry_rcu.
> >
> > Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
>
> You seem to have dropped the second hunk which modified
> xenvif_flush_hash, is that a mistake?
>

I am sorry again, Yes I forgot to add the second hunk.
I will send the final patch with both the hunks in a while.

Thank you,
Madhuparna

Wei.
>
> > ---
> >  drivers/net/xen-netback/hash.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/xen-netback/hash.c
> b/drivers/net/xen-netback/hash.c
> > index 10d580c3dea3..3f9783f70a75 100644
> > --- a/drivers/net/xen-netback/hash.c
> > +++ b/drivers/net/xen-netback/hash.c
> > @@ -51,7 +51,8 @@ static void xenvif_add_hash(struct xenvif *vif, const
> u8 *tag,
> >
> >       found = false;
> >       oldest = NULL;
> > -     list_for_each_entry_rcu(entry, &vif->hash.cache.list, link) {
> > +     list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
> > +                             lockdep_is_held(&vif->hash.cache.lock)) {
> >               /* Make sure we don't add duplicate entries */
> >               if (entry->len == len &&
> >                   memcmp(entry->tag, tag, len) == 0)
> > --
> > 2.17.1
> >
>
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