* for running devices in the if_list and sends packets until count is 0 it
* also the thread checks the thread->control which is used for inter-process
* communication. controlling process "posts" operations to the threads this
- * way. The if_lock should be possible to remove when add/rem_device is merged
- * into this too.
+ * way.
+ * The if_list is RCU protected, and the if_lock remains to protect updating
+ * of if_list, from "add_device" as it invoked from userspace (via proc write).
*
* By design there should only be *one* "controlling" process. In practice
* multiple write accesses gives unpredictable result. Understood by "write"
#define T_REMDEVALL (1<<2) /* Remove all devs */
#define T_REMDEV (1<<3) /* Remove one dev */
-/* If lock -- can be removed after some work */
+/* If lock -- protects updating of if_list */
#define if_lock(t) spin_lock(&(t->if_lock));
#define if_unlock(t) spin_unlock(&(t->if_lock));
struct proc_dir_entry *entry; /* proc file */
struct pktgen_thread *pg_thread;/* the owner */
struct list_head list; /* chaining in the thread's run-queue */
+ struct rcu_head rcu; /* freed by RCU */
int running; /* if false, the test will stop */
case '\t':
case ' ':
goto done_str;
- break;
default:
break;
}
seq_puts(seq, "Running: ");
- if_lock(t);
- list_for_each_entry(pkt_dev, &t->if_list, list)
+ rcu_read_lock();
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
if (pkt_dev->running)
seq_printf(seq, "%s ", pkt_dev->odevname);
seq_puts(seq, "\nStopped: ");
- list_for_each_entry(pkt_dev, &t->if_list, list)
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
if (!pkt_dev->running)
seq_printf(seq, "%s ", pkt_dev->odevname);
else
seq_puts(seq, "\nResult: NA\n");
- if_unlock(t);
+ rcu_read_unlock();
return 0;
}
pkt_dev = pktgen_find_dev(t, ifname, exact);
if (pkt_dev) {
if (remove) {
- if_lock(t);
pkt_dev->removal_mark = 1;
t->control |= T_REMDEV;
- if_unlock(t);
}
break;
}
list_for_each_entry(t, &pn->pktgen_threads, th_list) {
struct pktgen_dev *pkt_dev;
- list_for_each_entry(pkt_dev, &t->if_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
if (pkt_dev->odev != dev)
continue;
dev->name);
break;
}
+ rcu_read_unlock();
}
}
func_enter();
- if_lock(t);
- list_for_each_entry(pkt_dev, &t->if_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
/*
* setup odev and create initial packet.
if (pkt_dev->odev) {
pktgen_clear_counters(pkt_dev);
- pkt_dev->running = 1; /* Cranke yeself! */
pkt_dev->skb = NULL;
pkt_dev->started_at = pkt_dev->next_tx = ktime_get();
set_pkt_overhead(pkt_dev);
strcpy(pkt_dev->result, "Starting");
+ pkt_dev->running = 1; /* Cranke yeself! */
started++;
} else
strcpy(pkt_dev->result, "Error starting");
}
- if_unlock(t);
+ rcu_read_unlock();
if (started)
t->control &= ~(T_STOP);
}
{
const struct pktgen_dev *pkt_dev;
- list_for_each_entry(pkt_dev, &t->if_list, list)
- if (pkt_dev->running)
+ rcu_read_lock();
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list)
+ if (pkt_dev->running) {
+ rcu_read_unlock();
return 1;
+ }
+ rcu_read_unlock();
return 0;
}
static int pktgen_wait_thread_run(struct pktgen_thread *t)
{
- if_lock(t);
-
while (thread_is_running(t)) {
- if_unlock(t);
-
msleep_interruptible(100);
if (signal_pending(current))
goto signal;
- if_lock(t);
}
- if_unlock(t);
return 1;
signal:
return 0;
return -EINVAL;
}
+ pkt_dev->running = 0;
kfree_skb(pkt_dev->skb);
pkt_dev->skb = NULL;
pkt_dev->stopped_at = ktime_get();
- pkt_dev->running = 0;
show_results(pkt_dev, nr_frags);
{
struct pktgen_dev *pkt_dev, *best = NULL;
- if_lock(t);
-
- list_for_each_entry(pkt_dev, &t->if_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
if (!pkt_dev->running)
continue;
if (best == NULL)
else if (ktime_compare(pkt_dev->next_tx, best->next_tx) < 0)
best = pkt_dev;
}
- if_unlock(t);
+ rcu_read_unlock();
+
return best;
}
func_enter();
- if_lock(t);
+ rcu_read_lock();
- list_for_each_entry(pkt_dev, &t->if_list, list) {
+ list_for_each_entry_rcu(pkt_dev, &t->if_list, list) {
pktgen_stop_device(pkt_dev);
}
- if_unlock(t);
+ rcu_read_unlock();
}
/*
func_enter();
- if_lock(t);
-
list_for_each_safe(q, n, &t->if_list) {
cur = list_entry(q, struct pktgen_dev, list);
break;
}
-
- if_unlock(t);
}
static void pktgen_rem_all_ifs(struct pktgen_thread *t)
/* Remove all devices, free mem */
- if_lock(t);
-
list_for_each_safe(q, n, &t->if_list) {
cur = list_entry(q, struct pktgen_dev, list);
pktgen_remove_device(t, cur);
}
-
- if_unlock(t);
}
static void pktgen_rem_thread(struct pktgen_thread *t)
pr_debug("starting pktgen/%d: pid=%d\n", cpu, task_pid_nr(current));
- set_current_state(TASK_INTERRUPTIBLE);
-
set_freezable();
+ __set_current_state(TASK_RUNNING);
+
while (!kthread_should_stop()) {
pkt_dev = next_to_run(t);
continue;
}
- __set_current_state(TASK_RUNNING);
-
if (likely(pkt_dev)) {
pktgen_xmit(pkt_dev);
}
try_to_freeze();
-
- set_current_state(TASK_INTERRUPTIBLE);
}
+ set_current_state(TASK_INTERRUPTIBLE);
pr_debug("%s stopping all device\n", t->tsk->comm);
pktgen_stop(t);
struct pktgen_dev *p, *pkt_dev = NULL;
size_t len = strlen(ifname);
- if_lock(t);
- list_for_each_entry(p, &t->if_list, list)
+ rcu_read_lock();
+ list_for_each_entry_rcu(p, &t->if_list, list)
if (strncmp(p->odevname, ifname, len) == 0) {
if (p->odevname[len]) {
if (exact || p->odevname[len] != '@')
break;
}
- if_unlock(t);
+ rcu_read_unlock();
pr_debug("find_dev(%s) returning %p\n", ifname, pkt_dev);
return pkt_dev;
}
{
int rv = 0;
+ /* This function cannot be called concurrently, as its called
+ * under pktgen_thread_lock mutex, but it can run from
+ * userspace on another CPU than the kthread. The if_lock()
+ * is used here to sync with concurrent instances of
+ * _rem_dev_from_if_list() invoked via kthread, which is also
+ * updating the if_list */
if_lock(t);
if (pkt_dev->pg_thread) {
goto out;
}
- list_add(&pkt_dev->list, &t->if_list);
- pkt_dev->pg_thread = t;
pkt_dev->running = 0;
+ pkt_dev->pg_thread = t;
+ list_add_rcu(&pkt_dev->list, &t->if_list);
out:
if_unlock(t);
struct list_head *q, *n;
struct pktgen_dev *p;
+ if_lock(t);
list_for_each_safe(q, n, &t->if_list) {
p = list_entry(q, struct pktgen_dev, list);
if (p == pkt_dev)
- list_del(&p->list);
+ list_del_rcu(&p->list);
}
+ if_unlock(t);
}
static int pktgen_remove_device(struct pktgen_thread *t,
pkt_dev->odev = NULL;
}
- /* And update the thread if_list */
-
- _rem_dev_from_if_list(t, pkt_dev);
-
+ /* Remove proc before if_list entry, because add_device uses
+ * list to determine if interface already exist, avoid race
+ * with proc_create_data() */
if (pkt_dev->entry)
proc_remove(pkt_dev->entry);
+ /* And update the thread if_list */
+ _rem_dev_from_if_list(t, pkt_dev);
+
#ifdef CONFIG_XFRM
free_SAs(pkt_dev);
#endif
vfree(pkt_dev->flows);
if (pkt_dev->page)
put_page(pkt_dev->page);
- kfree(pkt_dev);
+ kfree_rcu(pkt_dev, rcu);
return 0;
}
{
unregister_netdevice_notifier(&pktgen_notifier_block);
unregister_pernet_subsys(&pg_net_ops);
+ /* Don't need rcu_barrier() due to use of kfree_rcu() */
}
module_init(pg_init);
projects / cascardo / linux.git / blobdiff