[v6,03/20] batman-adv: Convert batadv_gw_node to kref
Commit Message
batman-adv uses a self-written reference implementation which is just based
on atomic_t. This is less obvious when reading the code than kref and
therefore increases the change that the reference counting will be missed.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
v6:
- removed patches which are now applied in the branch next
- rebased remaining patches on the patch
"batman-adv: Avoid recursive call_rcu for batadv_nc_node" which was
modified by Marek while he applied the patches (this unfortunately made
some of the remaining patches "hard" to apply)
v5:
- add hack which allows to compile against stable kernel like 3.2.44 which
also added the kref_get_unless_zero function
v4:
- fix function names in commit messages
- fix double whitespace in batadv_tt_orig_list_entry_release kerneldoc
- add extra patch for batadv_claim_free_ref kerneldoc fix
- change the phrase "free it" in all *_free_ref/*_put functions to "release it"
v3:
- update copyright year
v2:
- split patchset into fixes and kref migration to make it easier when the
decision is made where each patch will be applied
net/batman-adv/gateway_client.c | 40 +++++++++++++++++++++++++++++-----------
net/batman-adv/types.h | 2 +-
2 files changed, 30 insertions(+), 12 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:41 Sven Eckelmann wrote:
> batman-adv uses a self-written reference implementation which is just based
> on atomic_t. This is less obvious when reading the code than kref and
> therefore increases the change that the reference counting will be missed.
>
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> v6:
> - removed patches which are now applied in the branch next
> - rebased remaining patches on the patch
> "batman-adv: Avoid recursive call_rcu for batadv_nc_node" which was
> modified by Marek while he applied the patches (this unfortunately made
> some of the remaining patches "hard" to apply)
> v5:
> - add hack which allows to compile against stable kernel like 3.2.44 which
> also added the kref_get_unless_zero function
> v4:
> - fix function names in commit messages
> - fix double whitespace in batadv_tt_orig_list_entry_release kerneldoc
> - add extra patch for batadv_claim_free_ref kerneldoc fix
> - change the phrase "free it" in all *_free_ref/*_put functions to "release
> it" v3:
> - update copyright year
> v2:
> - split patchset into fixes and kref migration to make it easier when the
> decision is made where each patch will be applied
>
> net/batman-adv/gateway_client.c | 40
> +++++++++++++++++++++++++++++-----------
> net/batman-adv/types.h | 2 +-
> 2 files changed, 30 insertions(+), 12 deletions(-)
Applied in revision 1faa4d8.
Thanks,
Marek
@@ -28,6 +28,7 @@
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/kernel.h>
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/rculist.h>
@@ -59,12 +60,29 @@
*/
#define BATADV_DHCP_CHADDR_OFFSET 28
+/**
+ * batadv_gw_node_release - release gw_node from lists and queue for free after
+ * rcu grace period
+ * @ref: kref pointer of the gw_node
+ */
+static void batadv_gw_node_release(struct kref *ref)
+{
+ struct batadv_gw_node *gw_node;
+
+ gw_node = container_of(ref, struct batadv_gw_node, refcount);
+
+ batadv_orig_node_free_ref(gw_node->orig_node);
+ kfree_rcu(gw_node, rcu);
+}
+
+/**
+ * batadv_gw_node_free_ref - decrement the gw_node refcounter and possibly
+ * release it
+ * @gw_node: gateway node to free
+ */
static void batadv_gw_node_free_ref(struct batadv_gw_node *gw_node)
{
- if (atomic_dec_and_test(&gw_node->refcount)) {
- batadv_orig_node_free_ref(gw_node->orig_node);
- kfree_rcu(gw_node, rcu);
- }
+ kref_put(&gw_node->refcount, batadv_gw_node_release);
}
static struct batadv_gw_node *
@@ -77,7 +95,7 @@ batadv_gw_get_selected_gw_node(struct batadv_priv *bat_priv)
if (!gw_node)
goto out;
- if (!atomic_inc_not_zero(&gw_node->refcount))
+ if (!kref_get_unless_zero(&gw_node->refcount))
gw_node = NULL;
out:
@@ -118,7 +136,7 @@ static void batadv_gw_select(struct batadv_priv *bat_priv,
spin_lock_bh(&bat_priv->gw.list_lock);
- if (new_gw_node && !atomic_inc_not_zero(&new_gw_node->refcount))
+ if (new_gw_node && !kref_get_unless_zero(&new_gw_node->refcount))
new_gw_node = NULL;
curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1);
@@ -170,7 +188,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
if (!router_ifinfo)
goto next;
- if (!atomic_inc_not_zero(&gw_node->refcount))
+ if (!kref_get_unless_zero(&gw_node->refcount))
goto next;
tq_avg = router_ifinfo->bat_iv.tq_avg;
@@ -188,7 +206,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
if (curr_gw)
batadv_gw_node_free_ref(curr_gw);
curr_gw = gw_node;
- atomic_inc(&curr_gw->refcount);
+ kref_get(&curr_gw->refcount);
}
break;
@@ -203,7 +221,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv *bat_priv)
if (curr_gw)
batadv_gw_node_free_ref(curr_gw);
curr_gw = gw_node;
- atomic_inc(&curr_gw->refcount);
+ kref_get(&curr_gw->refcount);
}
break;
}
@@ -436,7 +454,7 @@ static void batadv_gw_node_add(struct batadv_priv *bat_priv,
gw_node->orig_node = orig_node;
gw_node->bandwidth_down = ntohl(gateway->bandwidth_down);
gw_node->bandwidth_up = ntohl(gateway->bandwidth_up);
- atomic_set(&gw_node->refcount, 1);
+ kref_init(&gw_node->refcount);
spin_lock_bh(&bat_priv->gw.list_lock);
hlist_add_head_rcu(&gw_node->list, &bat_priv->gw.list);
@@ -469,7 +487,7 @@ batadv_gw_node_get(struct batadv_priv *bat_priv,
if (gw_node_tmp->orig_node != orig_node)
continue;
- if (!atomic_inc_not_zero(&gw_node_tmp->refcount))
+ if (!kref_get_unless_zero(&gw_node_tmp->refcount))
continue;
gw_node = gw_node_tmp;
@@ -342,7 +342,7 @@ struct batadv_gw_node {
struct batadv_orig_node *orig_node;
u32 bandwidth_down;
u32 bandwidth_up;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};