[PATCH] PKTGEN: Fix module load/unload races.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

net/core/pktgen.c

@@ -147,6 +147,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/wait.h>
+#include <linux/completion.h>
 #include <linux/etherdevice.h>
 #include <net/checksum.h>
 #include <net/ipv6.h>
@@ -206,6 +207,11 @@ static struct proc_dir_entry *pg_proc_dir = NULL;
 #define VLAN_TAG_SIZE(x) ((x)->vlan_id == 0xffff ? 0 : 4)
 #define SVLAN_TAG_SIZE(x) ((x)->svlan_id == 0xffff ? 0 : 4)
 
+struct pktgen_thread_info {
+       struct pktgen_thread *t;
+       struct completion *c;
+};
+
 struct flow_state {
 	__u32 cur_daddr;
 	int count;
@@ -3264,10 +3270,11 @@ out:;
  * Main loop of the thread goes here
  */
 
-static void pktgen_thread_worker(struct pktgen_thread *t)
+static void pktgen_thread_worker(struct pktgen_thread_info *info)
 {
 	DEFINE_WAIT(wait);
 	struct pktgen_dev *pkt_dev = NULL;
+	struct pktgen_thread *t = info->t;
 	int cpu = t->cpu;
 	sigset_t tmpsig;
 	u32 max_before_softirq;
@@ -3307,6 +3314,8 @@ static void pktgen_thread_worker(struct pktgen_thread *t)
 	__set_current_state(TASK_INTERRUPTIBLE);
 	mb();
 
+        complete(info->c);
+
 	while (1) {
 
 		__set_current_state(TASK_RUNNING);
@@ -3518,6 +3527,8 @@ static struct pktgen_thread *__init pktgen_find_thread(const char *name)
 static int __init pktgen_create_thread(const char *name, int cpu)
 {
 	int err;
+	struct pktgen_thread_info info;
+        struct completion started;
 	struct pktgen_thread *t = NULL;
 	struct proc_dir_entry *pe;
 
@@ -3558,7 +3569,11 @@ static int __init pktgen_create_thread(const char *name, int cpu)
 
 	t->removed = 0;
 
-	err = kernel_thread((void *)pktgen_thread_worker, (void *)t,
+	init_completion(&started);
+        info.t = t;
+        info.c = &started;
+
+	err = kernel_thread((void *)pktgen_thread_worker, (void *)&info,
 			  CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
 	if (err < 0) {
 		printk("pktgen: kernel_thread() failed for cpu %d\n", t->cpu);
@@ -3568,6 +3583,7 @@ static int __init pktgen_create_thread(const char *name, int cpu)
 		return err;
 	}
 
+	wait_for_completion(&started);
 	return 0;
 }