Re: [PATCHv3 next-next 1/1] net/mlx5: Fix build -Wframe-larger-than warnings

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

在 2025/7/20 9:08, Zhu Yanjun 写道:
> 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>

Sorry. Missing the following Acked-by.

Acked-by: Junxian Huang <huangjunxian6@hisilicon.com>

Zhu Yanjun

> ---
> v2 -> v3: No changes, just send out target net-next;
> v1 -> v2: Add kvfree to error handler;
> 
> 1. This commit only build tests;
> 2. All the changes are on configuration path, will not make difference
> on the performance;
> 3. This commit is just to fix build warnings, not error or bug fixes. So
> not Fixes tag.
> ---
>   drivers/net/ethernet/mellanox/mlx5/core/eq.c  | 24 +++++++----
>   .../mellanox/mlx5/core/irq_affinity.c         | 19 +++++++--
>   .../net/ethernet/mellanox/mlx5/core/pci_irq.c | 40 +++++++++++++------
>   3 files changed, 60 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> index dfb079e59d85..4938dd7c3a09 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> @@ -873,19 +873,29 @@ 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))
> +	if (!mlx5_irq_pool_is_sf_pool(pool)) {
> +		kvfree(af_desc);
>   		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);
> -	if (IS_ERR(irq))
> +	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)) {
> +		kvfree(af_desc);
>   		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",
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> index 2691d88cdee1..82d3c2568244 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> @@ -47,29 +47,40 @@ 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)
> +	if (err) {
> +		kvfree(auto_desc);
>   		return ERR_PTR(err);
> +	}
> +
>   	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 *