Commit 2d0b41a3 authored by Shay Drory's avatar Shay Drory Committed by Saeed Mahameed
Browse files

net/mlx5: Refcount mlx5_irq with integer 



Currently, all access to mlx5 IRQs are done undere a lock. Hance, there
isn't a reason to have kref in struct mlx5_irq.
Switch it to integer.

Signed-off-by: default avatarShay Drory <shayd@nvidia.com>
Reviewed-by: default avatarParav Pandit <parav@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent 68fefb70

drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c

+44 −21
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ struct mlx5_irq { 
	cpumask_var_t mask;

	char name[MLX5_MAX_IRQ_NAME];

	struct mlx5_irq_pool *pool;

	struct kref kref;

	int refcount;

	u32 index;

	int irqn;

};
@@ -138,9 +138,8 @@ int mlx5_set_msix_vec_count(struct mlx5_core_dev *dev, int function_id, 
	return ret;

}



static void irq_release(struct kref *kref)

static void irq_release(struct mlx5_irq *irq)

{

	struct mlx5_irq *irq = container_of(kref, struct mlx5_irq, kref);

	struct mlx5_irq_pool *pool = irq->pool;



	xa_erase(&pool->irqs, irq->index);
@@ -159,10 +158,31 @@ static void irq_put(struct mlx5_irq *irq) 
	struct mlx5_irq_pool *pool = irq->pool;



	mutex_lock(&pool->lock);

	kref_put(&irq->kref, irq_release);

	irq->refcount--;

	if (!irq->refcount)

		irq_release(irq);

	mutex_unlock(&pool->lock);

}



static int irq_get_locked(struct mlx5_irq *irq)

{

	lockdep_assert_held(&irq->pool->lock);

	if (WARN_ON_ONCE(!irq->refcount))

		return 0;

	irq->refcount++;

	return 1;

}



static int irq_get(struct mlx5_irq *irq)

{

	int err;



	mutex_lock(&irq->pool->lock);

	err = irq_get_locked(irq);

	mutex_unlock(&irq->pool->lock);

	return err;

}



static irqreturn_t irq_int_handler(int irq, void *nh)

{

	atomic_notifier_call_chain(nh, 0, NULL);
@@ -214,7 +234,7 @@ static struct mlx5_irq *irq_request(struct mlx5_irq_pool *pool, int i) 
		err = -ENOMEM;

		goto err_cpumask;

	}

	kref_init(&irq->kref);

	irq->refcount = 1;

	irq->index = i;

	err = xa_err(xa_store(&pool->irqs, irq->index, irq, GFP_KERNEL));

	if (err) {
@@ -235,18 +255,18 @@ static struct mlx5_irq *irq_request(struct mlx5_irq_pool *pool, int i) 


int mlx5_irq_attach_nb(struct mlx5_irq *irq, struct notifier_block *nb)

{

	int err;

	int ret;



	err = kref_get_unless_zero(&irq->kref);

	if (WARN_ON_ONCE(!err))

	ret = irq_get(irq);

	if (!ret)

		/* Something very bad happens here, we are enabling EQ

		 * on non-existing IRQ.

		 */

		return -ENOENT;

	err = atomic_notifier_chain_register(&irq->nh, nb);

	if (err)

	ret = atomic_notifier_chain_register(&irq->nh, nb);

	if (ret)

		irq_put(irq);

	return err;

	return ret;

}



int mlx5_irq_detach_nb(struct mlx5_irq *irq, struct notifier_block *nb)
@@ -301,10 +321,9 @@ static struct mlx5_irq *irq_pool_find_least_loaded(struct mlx5_irq_pool *pool, 
	xa_for_each_range(&pool->irqs, index, iter, start, end) {

		if (!cpumask_equal(iter->mask, affinity))

			continue;

		if (kref_read(&iter->kref) < pool->min_threshold)

		if (iter->refcount < pool->min_threshold)

			return iter;

		if (!irq || kref_read(&iter->kref) <

		    kref_read(&irq->kref))

		if (!irq || iter->refcount < irq->refcount)

			irq = iter;

	}

	return irq;
@@ -319,7 +338,7 @@ static struct mlx5_irq *irq_pool_request_affinity(struct mlx5_irq_pool *pool, 
	mutex_lock(&pool->lock);

	least_loaded_irq = irq_pool_find_least_loaded(pool, affinity);

	if (least_loaded_irq &&

	    kref_read(&least_loaded_irq->kref) < pool->min_threshold)

	    least_loaded_irq->refcount < pool->min_threshold)

		goto out;

	new_irq = irq_pool_create_irq(pool, affinity);

	if (IS_ERR(new_irq)) {
@@ -337,11 +356,11 @@ static struct mlx5_irq *irq_pool_request_affinity(struct mlx5_irq_pool *pool, 
	least_loaded_irq = new_irq;

	goto unlock;

out:

	kref_get(&least_loaded_irq->kref);

	if (kref_read(&least_loaded_irq->kref) > pool->max_threshold)

	irq_get_locked(least_loaded_irq);

	if (least_loaded_irq->refcount > pool->max_threshold)

		mlx5_core_dbg(pool->dev, "IRQ %u overloaded, pool_name: %s, %u EQs on this irq\n",

			      least_loaded_irq->irqn, pool->name,

			      kref_read(&least_loaded_irq->kref) / MLX5_EQ_REFS_PER_IRQ);

			      least_loaded_irq->refcount / MLX5_EQ_REFS_PER_IRQ);

unlock:

	mutex_unlock(&pool->lock);

	return least_loaded_irq;
@@ -357,7 +376,7 @@ irq_pool_request_vector(struct mlx5_irq_pool *pool, int vecidx, 
	mutex_lock(&pool->lock);

	irq = xa_load(&pool->irqs, vecidx);

	if (irq) {

		kref_get(&irq->kref);

		irq_get_locked(irq);

		goto unlock;

	}

	irq = irq_request(pool, vecidx);
@@ -424,7 +443,7 @@ struct mlx5_irq *mlx5_irq_request(struct mlx5_core_dev *dev, u16 vecidx, 
		return irq;

	mlx5_core_dbg(dev, "irq %u mapped to cpu %*pbl, %u EQs on this irq\n",

		      irq->irqn, cpumask_pr_args(affinity),

		      kref_read(&irq->kref) / MLX5_EQ_REFS_PER_IRQ);

		      irq->refcount / MLX5_EQ_REFS_PER_IRQ);

	return irq;

}
@@ -456,8 +475,12 @@ static void irq_pool_free(struct mlx5_irq_pool *pool) 
	struct mlx5_irq *irq;

	unsigned long index;



	/* There are cases in which we are destrying the irq_table before

	 * freeing all the IRQs, fast teardown for example. Hence, free the irqs

	 * which might not have been freed.

	 */

	xa_for_each(&pool->irqs, index, irq)

		irq_release(&irq->kref);

		irq_release(irq);

	xa_destroy(&pool->irqs);

	kvfree(pool);

}