iscsi-scst: Make iscsi_thread_pool locking more fine-grained

Protect iscsi_thread_pool.threads_list via tp_mutex instead of
scst_mutex.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5852 d57e44dd-8a1f-0410-8b47-8ef2f437770f

iscsi-scst/kernel/iscsi.c

@@ -3966,11 +3966,13 @@ static void __iscsi_threads_pool_put(struct iscsi_thread_pool *p)
 
 	TRACE_DBG("Freeing iSCSI thread pool %p", p);
 
+	mutex_lock(&p->tp_mutex);
 	list_for_each_entry_safe(t, tt, &p->threads_list, threads_list_entry) {
 		kthread_stop(t->thr);
 		list_del(&t->threads_list_entry);
 		kfree(t);
 	}
+	mutex_unlock(&p->tp_mutex);
 
 	list_del(&p->thread_pools_list_entry);
 
@@ -4046,6 +4048,7 @@ int iscsi_threads_pool_get(const cpumask_t *cpu_mask,
 	else
 		cpumask_copy(&p->cpu_mask, cpu_mask);
 	p->thread_pool_ref = 1;
+	mutex_init(&p->tp_mutex);
 	INIT_LIST_HEAD(&p->threads_list);
 
 	if (cpu_mask == NULL)
@@ -4077,7 +4080,10 @@ int iscsi_threads_pool_get(const cpumask_t *cpu_mask,
 				kfree(t);
 				goto out_free;
 			}
+
+			mutex_lock(&p->tp_mutex);
 			list_add_tail(&t->threads_list_entry, &p->threads_list);
+			mutex_unlock(&p->tp_mutex);
 		}
 	}
 

iscsi-scst/kernel/iscsi.h

@@ -85,9 +85,11 @@ struct iscsi_thread_pool {
 
 	int thread_pool_ref;
 
-	struct list_head threads_list;
-
+	/* Entry in iscsi_thread_pools_list */
 	struct list_head thread_pools_list_entry;
+
+	struct mutex tp_mutex;
+	struct list_head threads_list; /* protected by tp_mutex */
 };