[v6,14/20] batman-adv: Convert batadv_orig_ifinfo 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/originator.c | 15 +++++++++------
net/batman-adv/routing.c | 5 +++--
net/batman-adv/types.h | 2 +-
3 files changed, 13 insertions(+), 9 deletions(-)
Comments
On Saturday, January 16, 2016 10:29:52 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/originator.c | 15 +++++++++------
> net/batman-adv/routing.c | 5 +++--
> net/batman-adv/types.h | 2 +-
> 3 files changed, 13 insertions(+), 9 deletions(-)
Applied in revision 0d559d4.
Thanks,
Marek
@@ -326,7 +326,7 @@ batadv_orig_ifinfo_get(struct batadv_orig_node *orig_node,
if (tmp->if_outgoing != if_outgoing)
continue;
- if (!atomic_inc_not_zero(&tmp->refcount))
+ if (!kref_get_unless_zero(&tmp->refcount))
continue;
orig_ifinfo = tmp;
@@ -377,7 +377,8 @@ batadv_orig_ifinfo_new(struct batadv_orig_node *orig_node,
orig_ifinfo->batman_seqno_reset = reset_time;
orig_ifinfo->if_outgoing = if_outgoing;
INIT_HLIST_NODE(&orig_ifinfo->list);
- atomic_set(&orig_ifinfo->refcount, 2);
+ kref_init(&orig_ifinfo->refcount);
+ kref_get(&orig_ifinfo->refcount);
hlist_add_head_rcu(&orig_ifinfo->list,
&orig_node->ifinfo_list);
out:
@@ -704,12 +705,15 @@ int batadv_hardif_neigh_seq_print_text(struct seq_file *seq, void *offset)
/**
* batadv_orig_ifinfo_release - release orig_ifinfo from lists and queue for
* free after rcu grace period
- * @orig_ifinfo: the orig_ifinfo object to release
+ * @ref: kref pointer of the orig_ifinfo
*/
-static void batadv_orig_ifinfo_release(struct batadv_orig_ifinfo *orig_ifinfo)
+static void batadv_orig_ifinfo_release(struct kref *ref)
{
+ struct batadv_orig_ifinfo *orig_ifinfo;
struct batadv_neigh_node *router;
+ orig_ifinfo = container_of(ref, struct batadv_orig_ifinfo, refcount);
+
if (orig_ifinfo->if_outgoing != BATADV_IF_DEFAULT)
batadv_hardif_free_ref(orig_ifinfo->if_outgoing);
@@ -728,8 +732,7 @@ static void batadv_orig_ifinfo_release(struct batadv_orig_ifinfo *orig_ifinfo)
*/
void batadv_orig_ifinfo_free_ref(struct batadv_orig_ifinfo *orig_ifinfo)
{
- if (atomic_dec_and_test(&orig_ifinfo->refcount))
- batadv_orig_ifinfo_release(orig_ifinfo);
+ kref_put(&orig_ifinfo->refcount, batadv_orig_ifinfo_release);
}
/**
@@ -25,6 +25,7 @@
#include <linux/etherdevice.h>
#include <linux/if_ether.h>
#include <linux/jiffies.h>
+#include <linux/kref.h>
#include <linux/netdevice.h>
#include <linux/printk.h>
#include <linux/rculist.h>
@@ -497,7 +498,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
hlist_for_each_entry_rcu(cand, &orig_node->ifinfo_list, list) {
/* acquire some structures and references ... */
- if (!atomic_inc_not_zero(&cand->refcount))
+ if (!kref_get_unless_zero(&cand->refcount))
continue;
cand_router = rcu_dereference(cand->router);
@@ -524,7 +525,7 @@ batadv_find_router(struct batadv_priv *bat_priv,
/* mark the first possible candidate */
if (!first_candidate) {
atomic_inc(&cand_router->refcount);
- atomic_inc(&cand->refcount);
+ kref_get(&cand->refcount);
first_candidate = cand;
first_candidate_router = cand_router;
}
@@ -141,7 +141,7 @@ struct batadv_orig_ifinfo {
u32 last_real_seqno;
u8 last_ttl;
unsigned long batman_seqno_reset;
- atomic_t refcount;
+ struct kref refcount;
struct rcu_head rcu;
};