IB/ehca: Fix race condition/locking issues in scaling code
Fix a race condition in find_next_cpu_online() and some other locking issues in ehca scaling code. Signed-off-by: Hoang-Nam Nguyen <hnguyen@de.ibm.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
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@ -544,28 +544,30 @@ void ehca_tasklet_eq(unsigned long data)
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static inline int find_next_online_cpu(struct ehca_comp_pool* pool)
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{
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unsigned long flags_last_cpu;
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int cpu;
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unsigned long flags;
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WARN_ON_ONCE(!in_interrupt());
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if (ehca_debug_level)
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ehca_dmp(&cpu_online_map, sizeof(cpumask_t), "");
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spin_lock_irqsave(&pool->last_cpu_lock, flags_last_cpu);
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pool->last_cpu = next_cpu(pool->last_cpu, cpu_online_map);
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if (pool->last_cpu == NR_CPUS)
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pool->last_cpu = first_cpu(cpu_online_map);
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spin_unlock_irqrestore(&pool->last_cpu_lock, flags_last_cpu);
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spin_lock_irqsave(&pool->last_cpu_lock, flags);
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cpu = next_cpu(pool->last_cpu, cpu_online_map);
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if (cpu == NR_CPUS)
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cpu = first_cpu(cpu_online_map);
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pool->last_cpu = cpu;
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spin_unlock_irqrestore(&pool->last_cpu_lock, flags);
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return pool->last_cpu;
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return cpu;
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}
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static void __queue_comp_task(struct ehca_cq *__cq,
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struct ehca_cpu_comp_task *cct)
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{
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unsigned long flags_cct;
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unsigned long flags_cq;
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unsigned long flags;
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spin_lock_irqsave(&cct->task_lock, flags_cct);
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spin_lock_irqsave(&__cq->task_lock, flags_cq);
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spin_lock_irqsave(&cct->task_lock, flags);
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spin_lock(&__cq->task_lock);
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if (__cq->nr_callbacks == 0) {
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__cq->nr_callbacks++;
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@ -576,8 +578,8 @@ static void __queue_comp_task(struct ehca_cq *__cq,
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else
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__cq->nr_callbacks++;
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spin_unlock_irqrestore(&__cq->task_lock, flags_cq);
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spin_unlock_irqrestore(&cct->task_lock, flags_cct);
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spin_unlock(&__cq->task_lock);
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spin_unlock_irqrestore(&cct->task_lock, flags);
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}
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static void queue_comp_task(struct ehca_cq *__cq)
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@ -588,69 +590,69 @@ static void queue_comp_task(struct ehca_cq *__cq)
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cpu = get_cpu();
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cpu_id = find_next_online_cpu(pool);
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BUG_ON(!cpu_online(cpu_id));
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cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
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BUG_ON(!cct);
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if (cct->cq_jobs > 0) {
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cpu_id = find_next_online_cpu(pool);
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cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
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BUG_ON(!cct);
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}
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__queue_comp_task(__cq, cct);
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put_cpu();
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return;
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}
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static void run_comp_task(struct ehca_cpu_comp_task* cct)
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{
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struct ehca_cq *cq;
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unsigned long flags_cct;
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unsigned long flags_cq;
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unsigned long flags;
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spin_lock_irqsave(&cct->task_lock, flags_cct);
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spin_lock_irqsave(&cct->task_lock, flags);
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while (!list_empty(&cct->cq_list)) {
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cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
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spin_unlock_irqrestore(&cct->task_lock, flags_cct);
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spin_unlock_irqrestore(&cct->task_lock, flags);
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comp_event_callback(cq);
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spin_lock_irqsave(&cct->task_lock, flags_cct);
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spin_lock_irqsave(&cct->task_lock, flags);
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spin_lock_irqsave(&cq->task_lock, flags_cq);
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spin_lock(&cq->task_lock);
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cq->nr_callbacks--;
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if (cq->nr_callbacks == 0) {
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list_del_init(cct->cq_list.next);
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cct->cq_jobs--;
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}
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spin_unlock_irqrestore(&cq->task_lock, flags_cq);
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spin_unlock(&cq->task_lock);
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}
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spin_unlock_irqrestore(&cct->task_lock, flags_cct);
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return;
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spin_unlock_irqrestore(&cct->task_lock, flags);
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}
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static int comp_task(void *__cct)
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{
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struct ehca_cpu_comp_task* cct = __cct;
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int cql_empty;
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DECLARE_WAITQUEUE(wait, current);
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set_current_state(TASK_INTERRUPTIBLE);
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while(!kthread_should_stop()) {
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add_wait_queue(&cct->wait_queue, &wait);
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if (list_empty(&cct->cq_list))
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spin_lock_irq(&cct->task_lock);
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cql_empty = list_empty(&cct->cq_list);
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spin_unlock_irq(&cct->task_lock);
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if (cql_empty)
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schedule();
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else
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__set_current_state(TASK_RUNNING);
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remove_wait_queue(&cct->wait_queue, &wait);
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if (!list_empty(&cct->cq_list))
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spin_lock_irq(&cct->task_lock);
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cql_empty = list_empty(&cct->cq_list);
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spin_unlock_irq(&cct->task_lock);
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if (!cql_empty)
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run_comp_task(__cct);
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set_current_state(TASK_INTERRUPTIBLE);
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@ -693,8 +695,6 @@ static void destroy_comp_task(struct ehca_comp_pool *pool,
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if (task)
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kthread_stop(task);
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return;
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}
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static void take_over_work(struct ehca_comp_pool *pool,
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@ -815,6 +815,4 @@ void ehca_destroy_comp_pool(void)
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free_percpu(pool->cpu_comp_tasks);
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kfree(pool);
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#endif
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return;
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}
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