{
struct vport *vport;
- vport_lock();
vport = vport_add(parms);
if (!IS_ERR(vport)) {
struct datapath *dp = parms->dp;
dp_ifinfo_notify(RTM_NEWLINK, vport);
}
- vport_unlock();
return vport;
}
int dp_detach_port(struct vport *p)
{
- int err;
-
ASSERT_RTNL();
if (p->port_no != ODPP_LOCAL)
rcu_assign_pointer(p->dp->ports[p->port_no], NULL);
/* Then destroy it. */
- vport_lock();
- err = vport_del(p);
- vport_unlock();
-
- return err;
+ return vport_del(p);
}
/* Must be called with rcu_read_lock. */
struct vport *vport;
int dp_idx;
- vport_lock();
+ rcu_read_lock();
vport = vport_locate(nla_data(a[ODP_DP_ATTR_NAME]));
dp_idx = vport && vport->port_no == ODPP_LOCAL ? vport->dp->dp_idx : -1;
- vport_unlock();
+ rcu_read_unlock();
if (dp_idx < 0)
return ERR_PTR(-ENODEV);
int dp_idx, port_no;
retry:
- vport_lock();
+ rcu_read_lock();
vport = vport_locate(nla_data(a[ODP_VPORT_ATTR_NAME]));
if (!vport) {
- vport_unlock();
+ rcu_read_unlock();
return ERR_PTR(-ENODEV);
}
dp_idx = vport->dp->dp_idx;
port_no = vport->port_no;
- vport_unlock();
+ rcu_read_unlock();
dp = get_dp_locked(dp_idx);
if (!dp)
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/percpu.h>
+#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <linux/compat.h>
#include <linux/version.h>
static const struct vport_ops **vport_ops_list;
static int n_vport_types;
+/* Protected by RCU read lock for reading, RTNL lock for writing. */
static struct hlist_head *dev_table;
#define VPORT_HASH_BUCKETS 1024
-/* Both RTNL lock and vport_mutex need to be held when updating dev_table.
- *
- * If you use vport_locate and then perform some operations, you need to hold
- * one of these locks if you don't want the vport to be deleted out from under
- * you.
- *
- * If you get a reference to a vport through a datapath, it is protected
- * by RCU and you need to hold rcu_read_lock instead when reading.
- *
- * If multiple locks are taken, the hierarchy is:
- * 1. RTNL
- * 2. DP
- * 3. vport
- */
-static DEFINE_MUTEX(vport_mutex);
-
-/**
- * vport_lock - acquire vport lock
- *
- * Acquire global vport lock. See above comment about locking requirements
- * and specific function definitions. May sleep.
- */
-void vport_lock(void)
-{
- mutex_lock(&vport_mutex);
-}
-
-/**
- * vport_unlock - release vport lock
- *
- * Release lock acquired with vport_lock.
- */
-void vport_unlock(void)
-{
- mutex_unlock(&vport_mutex);
-}
-
-#define ASSERT_VPORT() \
-do { \
- if (unlikely(!mutex_is_locked(&vport_mutex))) { \
- pr_err("vport lock not held at %s (%d)\n", \
- __FILE__, __LINE__); \
- dump_stack(); \
- } \
-} while (0)
-
/**
* vport_init - initialize vport subsystem
*
*
* @name: name of port to find
*
- * Either RTNL or vport lock must be acquired before calling this function
- * and held while using the found port. See the locking comments at the
- * top of the file.
+ * Must be called with RTNL or RCU read lock.
*/
struct vport *vport_locate(const char *name)
{
struct vport *vport;
struct hlist_node *node;
- if (unlikely(!mutex_is_locked(&vport_mutex) && !rtnl_is_locked())) {
- pr_err("neither RTNL nor vport lock held in vport_locate\n");
- dump_stack();
- }
-
- rcu_read_lock();
-
- hlist_for_each_entry(vport, node, bucket, hash_node)
+ hlist_for_each_entry_rcu(vport, node, bucket, hash_node)
if (!strcmp(name, vport_get_name(vport)))
- goto out;
-
- vport = NULL;
-
-out:
- rcu_read_unlock();
- return vport;
-}
-
-static void register_vport(struct vport *vport)
-{
- hlist_add_head(&vport->hash_node, hash_bucket(vport_get_name(vport)));
-}
+ return vport;
-static void unregister_vport(struct vport *vport)
-{
- hlist_del(&vport->hash_node);
+ return NULL;
}
static void release_vport(struct kobject *kobj)
* @vport: vport to free
*
* Frees a vport allocated with vport_alloc() when it is no longer needed.
+ *
+ * The caller must ensure that an RCU grace period has passed since the last
+ * time @vport was in a datapath.
*/
void vport_free(struct vport *vport)
{
* @parms: Information about new vport.
*
* Creates a new vport with the specified configuration (which is dependent on
- * device type) and attaches it to a datapath. Both RTNL and vport locks must
- * be held.
+ * device type) and attaches it to a datapath. RTNL lock must be held.
*/
struct vport *vport_add(const struct vport_parms *parms)
{
int i;
ASSERT_RTNL();
- ASSERT_VPORT();
for (i = 0; i < n_vport_types; i++) {
if (vport_ops_list[i]->type == parms->type) {
goto out;
}
- register_vport(vport);
+ hlist_add_head_rcu(&vport->hash_node,
+ hash_bucket(vport_get_name(vport)));
return vport;
}
}
* @vport: vport to delete.
*
* Detaches @vport from its datapath and destroys it. It is possible to fail
- * for reasons such as lack of memory. Both RTNL and vport locks must be held.
+ * for reasons such as lack of memory. RTNL lock must be held.
*/
int vport_del(struct vport *vport)
{
ASSERT_RTNL();
- ASSERT_VPORT();
- unregister_vport(vport);
+ hlist_del_rcu(&vport->hash_node);
return vport->ops->destroy(vport);
}
/* The following definitions are for users of the vport subsytem: */
-void vport_lock(void);
-void vport_unlock(void);
-
int vport_init(void);
void vport_exit(void);
/**
* struct vport - one port within a datapath
+ * @rcu: RCU callback head for deferred destruction.
* @port_no: Index into @dp's @ports array.
* @dp: Datapath to which this port belongs.
* @kobj: Represents /sys/class/net/<devname>/brport.
* XAPI for Citrix XenServer. Deprecated.
*/
struct vport {
+ struct rcu_head rcu;
u16 port_no;
struct datapath *dp;
struct kobject kobj;
* @exit: Called at module unload.
* @create: Create a new vport configured as specified. On success returns
* a new vport allocated with vport_alloc(), otherwise an ERR_PTR() value.
- * @destroy: Detach and destroy a vport.
+ * @destroy: Destroys a vport. Must call vport_free() on the vport but not
+ * before an RCU grace period has elapsed.
* @set_options: Modify the configuration of an existing vport. May be %NULL
* if modification is not supported.
* @get_options: Appends vport-specific attributes for the configuration of an
projects / openvswitch / commitdiff