2016-03-11 12:41:25

by SF Markus Elfring

[permalink] [raw]
Subject: [PATCH] batman-adv: Less function calls in batadv_is_ap_isolated() after error detection

From: Markus Elfring <[email protected]>
Date: Fri, 11 Mar 2016 13:10:20 +0100

The variables "tt_local_entry" and "tt_global_entry" were eventually
checked again despite of a corresponding null pointer test before.

* Avoid this double check by reordering a function call sequence
and the better selection of jump targets.

* Omit the initialisation for these variables at the beginning then.

Signed-off-by: Markus Elfring <[email protected]>
---
net/batman-adv/translation-table.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 0b43e86..9c0193ee 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -3403,8 +3403,8 @@ void batadv_tt_local_commit_changes(struct batadv_priv *bat_priv)
bool batadv_is_ap_isolated(struct batadv_priv *bat_priv, u8 *src, u8 *dst,
unsigned short vid)
{
- struct batadv_tt_local_entry *tt_local_entry = NULL;
- struct batadv_tt_global_entry *tt_global_entry = NULL;
+ struct batadv_tt_local_entry *tt_local_entry;
+ struct batadv_tt_global_entry *tt_global_entry;
struct batadv_softif_vlan *vlan;
bool ret = false;

@@ -3413,27 +3413,24 @@ bool batadv_is_ap_isolated(struct batadv_priv *bat_priv, u8 *src, u8 *dst,
return false;

if (!atomic_read(&vlan->ap_isolation))
- goto out;
+ goto vlan_put;

tt_local_entry = batadv_tt_local_hash_find(bat_priv, dst, vid);
if (!tt_local_entry)
- goto out;
+ goto vlan_put;

tt_global_entry = batadv_tt_global_hash_find(bat_priv, src, vid);
if (!tt_global_entry)
- goto out;
-
- if (!_batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
- goto out;
+ goto local_entry_put;

- ret = true;
+ if (_batadv_is_ap_isolated(tt_local_entry, tt_global_entry))
+ ret = true;

-out:
+ batadv_tt_global_entry_put(tt_global_entry);
+local_entry_put:
+ batadv_tt_local_entry_put(tt_local_entry);
+vlan_put:
batadv_softif_vlan_put(vlan);
- if (tt_global_entry)
- batadv_tt_global_entry_put(tt_global_entry);
- if (tt_local_entry)
- batadv_tt_local_entry_put(tt_local_entry);
return ret;
}

--
2.7.2


2016-03-14 19:25:11

by David Miller

[permalink] [raw]
Subject: Re: [PATCH] batman-adv: Less function calls in batadv_is_ap_isolated() after error detection

From: SF Markus Elfring <[email protected]>
Date: Fri, 11 Mar 2016 13:40:56 +0100

> From: Markus Elfring <[email protected]>
> Date: Fri, 11 Mar 2016 13:10:20 +0100
>
> The variables "tt_local_entry" and "tt_global_entry" were eventually
> checked again despite of a corresponding null pointer test before.
>
> * Avoid this double check by reordering a function call sequence
> and the better selection of jump targets.
>
> * Omit the initialisation for these variables at the beginning then.
>
> Signed-off-by: Markus Elfring <[email protected]>

I am assuming Antonio will take this in via his tree.

2016-03-15 00:15:29

by Antonio Quartulli

[permalink] [raw]
Subject: Re: [PATCH] batman-adv: Less function calls in batadv_is_ap_isolated() after error detection

On Mon, Mar 14, 2016 at 03:25:02PM -0400, David Miller wrote:
> From: SF Markus Elfring <[email protected]>
> Date: Fri, 11 Mar 2016 13:40:56 +0100
>
> > From: Markus Elfring <[email protected]>
> > Date: Fri, 11 Mar 2016 13:10:20 +0100
> >
> > The variables "tt_local_entry" and "tt_global_entry" were eventually
> > checked again despite of a corresponding null pointer test before.
> >
> > * Avoid this double check by reordering a function call sequence
> > and the better selection of jump targets.
> >
> > * Omit the initialisation for these variables at the beginning then.
> >
> > Signed-off-by: Markus Elfring <[email protected]>
>
> I am assuming Antonio will take this in via his tree.
>

Yeah, it will go through our tree. Still under review right now.

Cheers,

--
Antonio Quartulli


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