[v6,12/20] batman-adv: Convert batadv_tt_orig_list_entry 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/translation-table.c | 26 +++++++++++++++++---------
net/batman-adv/types.h | 2 +-
2 files changed, 18 insertions(+), 10 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:50 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/translation-table.c | 26 +++++++++++++++++---------
> net/batman-adv/types.h | 2 +-
> 2 files changed, 18 insertions(+), 10 deletions(-)
Applied in revision d63fa57.
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>
@@ -346,22 +347,28 @@ static void batadv_tt_global_size_dec(struct batadv_orig_node *orig_node,
/**
* batadv_tt_orig_list_entry_release - release tt orig entry from lists and
* queue for free after rcu grace period
- * @orig_entry: tt orig entry to be free'd
+ * @ref: kref pointer of the tt orig entry
*/
-static void
-batadv_tt_orig_list_entry_release(struct batadv_tt_orig_list_entry *orig_entry)
+static void batadv_tt_orig_list_entry_release(struct kref *ref)
{
+ struct batadv_tt_orig_list_entry *orig_entry;
+
+ orig_entry = container_of(ref, struct batadv_tt_orig_list_entry,
+ refcount);
+
batadv_orig_node_free_ref(orig_entry->orig_node);
kfree_rcu(orig_entry, rcu);
}
+/**
+ * batadv_tt_orig_list_entry_free_ref - decrement the tt orig entry refcounter
+ * and possibly release it
+ * @orig_entry: tt orig entry to be free'd
+ */
static void
batadv_tt_orig_list_entry_free_ref(struct batadv_tt_orig_list_entry *orig_entry)
{
- if (!atomic_dec_and_test(&orig_entry->refcount))
- return;
-
- batadv_tt_orig_list_entry_release(orig_entry);
+ kref_put(&orig_entry->refcount, batadv_tt_orig_list_entry_release);
}
/**
@@ -1270,7 +1277,7 @@ batadv_tt_global_orig_entry_find(const struct batadv_tt_global_entry *entry,
hlist_for_each_entry_rcu(tmp_orig_entry, head, list) {
if (tmp_orig_entry->orig_node != orig_node)
continue;
- if (!atomic_inc_not_zero(&tmp_orig_entry->refcount))
+ if (!kref_get_unless_zero(&tmp_orig_entry->refcount))
continue;
orig_entry = tmp_orig_entry;
@@ -1331,7 +1338,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
batadv_tt_global_size_inc(orig_node, tt_global->common.vid);
orig_entry->orig_node = orig_node;
orig_entry->ttvn = ttvn;
- atomic_set(&orig_entry->refcount, 2);
+ kref_init(&orig_entry->refcount);
+ kref_get(&orig_entry->refcount);
spin_lock_bh(&tt_global->list_lock);
hlist_add_head_rcu(&orig_entry->list,
@@ -1014,7 +1014,7 @@ struct batadv_tt_orig_list_entry {
struct batadv_orig_node *orig_node;
u8 ttvn;
struct hlist_node list;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};