[v6,05/20] batman-adv: Convert batadv_bla_backbone_gw 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/bridge_loop_avoidance.c | 29 +++++++++++++++++++++++------
net/batman-adv/types.h | 2 +-
2 files changed, 24 insertions(+), 7 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:43 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/bridge_loop_avoidance.c | 29 +++++++++++++++++++++++------
> net/batman-adv/types.h | 2 +-
> 2 files changed, 24 insertions(+), 7 deletions(-)
Applied in revision cda4d54.
Thanks,
Marek
@@ -31,6 +31,7 @@
#include <linux/jhash.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/netdevice.h>
@@ -143,14 +144,29 @@ static int batadv_compare_claim(const struct hlist_node *node,
}
/**
- * batadv_compare_backbone_gw - free backbone gw
+ * batadv_backbone_gw_release - release backbone gw from lists and queue for
+ * free after rcu grace period
+ * @ref: kref pointer of the backbone gw
+ */
+static void batadv_backbone_gw_release(struct kref *ref)
+{
+ struct batadv_bla_backbone_gw *backbone_gw;
+
+ backbone_gw = container_of(ref, struct batadv_bla_backbone_gw,
+ refcount);
+
+ kfree_rcu(backbone_gw, rcu);
+}
+
+/**
+ * batadv_backbone_gw_free_ref - decrement the backbone gw refcounter and
+ * possibly release it
* @backbone_gw: backbone gateway to be free'd
*/
static void
batadv_backbone_gw_free_ref(struct batadv_bla_backbone_gw *backbone_gw)
{
- if (atomic_dec_and_test(&backbone_gw->refcount))
- kfree_rcu(backbone_gw, rcu);
+ kref_put(&backbone_gw->refcount, batadv_backbone_gw_release);
}
/**
@@ -247,7 +263,7 @@ batadv_backbone_hash_find(struct batadv_priv *bat_priv, u8 *addr,
&search_entry))
continue;
- if (!atomic_inc_not_zero(&backbone_gw->refcount))
+ if (!kref_get_unless_zero(&backbone_gw->refcount))
continue;
backbone_gw_tmp = backbone_gw;
@@ -448,7 +464,8 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, u8 *orig,
ether_addr_copy(entry->orig, orig);
/* one for the hash, one for returning */
- atomic_set(&entry->refcount, 2);
+ kref_init(&entry->refcount);
+ kref_get(&entry->refcount);
hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
batadv_compare_backbone_gw,
@@ -664,7 +681,7 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
batadv_backbone_gw_free_ref(claim->backbone_gw);
}
/* set (new) backbone gw */
- atomic_inc(&backbone_gw->refcount);
+ kref_get(&backbone_gw->refcount);
claim->backbone_gw = backbone_gw;
spin_lock_bh(&backbone_gw->crc_lock);
@@ -930,7 +930,7 @@ struct batadv_bla_backbone_gw {
atomic_t request_sent;
u16 crc;
spinlock_t crc_lock; /* protects crc */
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};