Re: [PATCH rdma-next 1/1] net/mlx5: Fix build -Wframe-larger-than warnings

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2025/7/9 21:09, Junxian Huang 写道:
>
> On 2025/7/10 11:49, Zhu Yanjun wrote:
>> When building, the following warnings will appear.
>> "
>> pci_irq.c: In function ‘mlx5_ctrl_irq_request’:
>> pci_irq.c:494:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>
>> pci_irq.c: In function ‘mlx5_irq_request_vector’:
>> pci_irq.c:561:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>
>> eq.c: In function ‘comp_irq_request_sf’:
>> eq.c:897:1: warning: the frame size of 1080 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>
>> irq_affinity.c: In function ‘irq_pool_request_irq’:
>> irq_affinity.c:74:1: warning: the frame size of 1048 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>> "
>>
>> These warnings indicate that the stack frame size exceeds 1024 bytes in
>> these functions.
>>
>> To resolve this, instead of allocating large memory buffers on the stack,
>> it is better to use kvzalloc to allocate memory dynamically on the heap.
>> This approach reduces stack usage and eliminates these frame size warnings.
>>
>> Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
>> ---
>> 1. Only build tests;
>> 2. It is not a bug fix. Thus no Fixes tag;
>> ---
>>   drivers/net/ethernet/mellanox/mlx5/core/eq.c  | 16 +++++---
>>   .../mellanox/mlx5/core/irq_affinity.c         | 15 +++++--
>>   .../net/ethernet/mellanox/mlx5/core/pci_irq.c | 40 +++++++++++++------
>>   3 files changed, 51 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
>> index dfb079e59d85..66ce61eee804 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
>> @@ -873,20 +873,26 @@ static int comp_irq_request_sf(struct mlx5_core_dev *dev, u16 vecidx)
>>   {
>>   	struct mlx5_irq_pool *pool = mlx5_irq_table_get_comp_irq_pool(dev);
>>   	struct mlx5_eq_table *table = dev->priv.eq_table;
>> -	struct irq_affinity_desc af_desc = {};
>> +	struct irq_affinity_desc *af_desc;
>>   	struct mlx5_irq *irq;
>>   
>> +	af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
>> +	if (!af_desc)
>> +		return -ENOMEM;
>> +
>>   	/* In case SF irq pool does not exist, fallback to the PF irqs*/
>>   	if (!mlx5_irq_pool_is_sf_pool(pool))
>>   		return comp_irq_request_pci(dev, vecidx);
> ...
>
>>   
>> -	af_desc.is_managed = false;
>> -	cpumask_copy(&af_desc.mask, cpu_online_mask);
>> -	cpumask_andnot(&af_desc.mask, &af_desc.mask, &table->used_cpus);
>> -	irq = mlx5_irq_affinity_request(dev, pool, &af_desc);
>> +	af_desc->is_managed = false;
>> +	cpumask_copy(&af_desc->mask, cpu_online_mask);
>> +	cpumask_andnot(&af_desc->mask, &af_desc->mask, &table->used_cpus);
>> +	irq = mlx5_irq_affinity_request(dev, pool, af_desc);
>>   	if (IS_ERR(irq))
>>   		return PTR_ERR(irq);
> ...
>
>>   
>> +	kvfree(af_desc);
>> +
>>   	cpumask_or(&table->used_cpus, &table->used_cpus, mlx5_irq_get_affinity_mask(irq));
>>   	mlx5_core_dbg(pool->dev, "IRQ %u mapped to cpu %*pbl, %u EQs on this irq\n",
>>   		      pci_irq_vector(dev->pdev, mlx5_irq_get_index(irq)),
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
>> index 2691d88cdee1..929f93853843 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
>> @@ -47,29 +47,38 @@ static int cpu_get_least_loaded(struct mlx5_irq_pool *pool,
>>   static struct mlx5_irq *
>>   irq_pool_request_irq(struct mlx5_irq_pool *pool, struct irq_affinity_desc *af_desc)
>>   {
>> -	struct irq_affinity_desc auto_desc = {};
>> +	struct irq_affinity_desc *auto_desc;
>>   	struct mlx5_irq *irq;
>>   	u32 irq_index;
>>   	int err;
>>   
>> +	auto_desc = kvzalloc(sizeof(*auto_desc), GFP_KERNEL);
>> +	if (!auto_desc)
>> +		return ERR_PTR(-ENOMEM);
>> +
>>   	err = xa_alloc(&pool->irqs, &irq_index, NULL, pool->xa_num_irqs, GFP_KERNEL);
>>   	if (err)
>>   		return ERR_PTR(err);
> You forgot to free the kvzalloc() memory in these error branches

Thanks a lot. I will fix it ASAP.

Yanjun.Zhu

>
> Junxian
>
>> +
>>   	if (pool->irqs_per_cpu) {
>>   		if (cpumask_weight(&af_desc->mask) > 1)
>>   			/* if req_mask contain more then one CPU, set the least loadad CPU
>>   			 * of req_mask
>>   			 */
>>   			cpumask_set_cpu(cpu_get_least_loaded(pool, &af_desc->mask),
>> -					&auto_desc.mask);
>> +					&auto_desc->mask);
>>   		else
>>   			cpu_get(pool, cpumask_first(&af_desc->mask));
>>   	}
>> +
>>   	irq = mlx5_irq_alloc(pool, irq_index,
>> -			     cpumask_empty(&auto_desc.mask) ? af_desc : &auto_desc,
>> +			     cpumask_empty(&auto_desc->mask) ? af_desc : auto_desc,
>>   			     NULL);
>>   	if (IS_ERR(irq))
>>   		xa_erase(&pool->irqs, irq_index);
>> +
>> +	kvfree(auto_desc);
>> +
>>   	return irq;
>>   }
>>   
>> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
>> index 40024cfa3099..48aad94b0a5d 100644
>> --- a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
>> +++ b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
>> @@ -470,26 +470,32 @@ void mlx5_ctrl_irq_release(struct mlx5_core_dev *dev, struct mlx5_irq *ctrl_irq)
>>   struct mlx5_irq *mlx5_ctrl_irq_request(struct mlx5_core_dev *dev)
>>   {
>>   	struct mlx5_irq_pool *pool = ctrl_irq_pool_get(dev);
>> -	struct irq_affinity_desc af_desc;
>> +	struct irq_affinity_desc *af_desc;
>>   	struct mlx5_irq *irq;
>>   
>> -	cpumask_copy(&af_desc.mask, cpu_online_mask);
>> -	af_desc.is_managed = false;
>> +	af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
>> +	if (!af_desc)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	cpumask_copy(&af_desc->mask, cpu_online_mask);
>> +	af_desc->is_managed = false;
>>   	if (!mlx5_irq_pool_is_sf_pool(pool)) {
>>   		/* In case we are allocating a control IRQ from a pci device's pool.
>>   		 * This can happen also for a SF if the SFs pool is empty.
>>   		 */
>>   		if (!pool->xa_num_irqs.max) {
>> -			cpumask_clear(&af_desc.mask);
>> +			cpumask_clear(&af_desc->mask);
>>   			/* In case we only have a single IRQ for PF/VF */
>> -			cpumask_set_cpu(cpumask_first(cpu_online_mask), &af_desc.mask);
>> +			cpumask_set_cpu(cpumask_first(cpu_online_mask), &af_desc->mask);
>>   		}
>>   		/* Allocate the IRQ in index 0. The vector was already allocated */
>> -		irq = irq_pool_request_vector(pool, 0, &af_desc, NULL);
>> +		irq = irq_pool_request_vector(pool, 0, af_desc, NULL);
>>   	} else {
>> -		irq = mlx5_irq_affinity_request(dev, pool, &af_desc);
>> +		irq = mlx5_irq_affinity_request(dev, pool, af_desc);
>>   	}
>>   
>> +	kvfree(af_desc);
>> +
>>   	return irq;
>>   }
>>   
>> @@ -548,16 +554,26 @@ struct mlx5_irq *mlx5_irq_request_vector(struct mlx5_core_dev *dev, u16 cpu,
>>   {
>>   	struct mlx5_irq_table *table = mlx5_irq_table_get(dev);
>>   	struct mlx5_irq_pool *pool = table->pcif_pool;
>> -	struct irq_affinity_desc af_desc;
>> +	struct irq_affinity_desc *af_desc;
>>   	int offset = MLX5_IRQ_VEC_COMP_BASE;
>> +	struct mlx5_irq *irq;
>> +
>> +	af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
>> +	if (!af_desc)
>> +		return ERR_PTR(-ENOMEM);
>>   
>>   	if (!pool->xa_num_irqs.max)
>>   		offset = 0;
>>   
>> -	af_desc.is_managed = false;
>> -	cpumask_clear(&af_desc.mask);
>> -	cpumask_set_cpu(cpu, &af_desc.mask);
>> -	return mlx5_irq_request(dev, vecidx + offset, &af_desc, rmap);
>> +	af_desc->is_managed = false;
>> +	cpumask_clear(&af_desc->mask);
>> +	cpumask_set_cpu(cpu, &af_desc->mask);
>> +
>> +	irq = mlx5_irq_request(dev, vecidx + offset, af_desc, rmap);
>> +
>> +	kvfree(af_desc);
>> +
>> +	return irq;
>>   }
>>   
>>   static struct mlx5_irq_pool *

-- 
Best Regards,
Yanjun.Zhu