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Date: Wed, 11 Aug 2021 11:16:52 -0700
From: Saeed Mahameed <saeed@...nel.org>
To: "David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org, Tariq Toukan <tariqt@...dia.com>,
Leon Romanovsky <leonro@...dia.com>,
Shay Drory <shayd@...dia.com>, Parav Pandit <parav@...dia.com>,
Saeed Mahameed <saeedm@...dia.com>
Subject: [net-next 06/12] net/mlx5: Refcount mlx5_irq with integer
From: Shay Drory <shayd@...dia.com>
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: Shay Drory <shayd@...dia.com>
Reviewed-by: Parav Pandit <parav@...dia.com>
Signed-off-by: Saeed Mahameed <saeedm@...dia.com>
---
.../net/ethernet/mellanox/mlx5/core/pci_irq.c | 65 +++++++++++++------
1 file changed, 44 insertions(+), 21 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
index 717b9f1850ac..60bfcad1873c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
@@ -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);
}
--
2.31.1
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