net/mlx5: Increase size of irq name buffer

[ Upstream commit 3338beb ]

Without increased buffer size, will trigger -Wformat-truncation with W=1
for the snprintf operation writing to the buffer.

    drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c: In function 'mlx5_irq_alloc':
    drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c:296:7: error: '@pci:' directive output may be truncated writing 5 bytes into a region of size between 1 and 32 [-Werror=format-truncation=]
      296 |    "%s@pci:%s", name, pci_name(dev->pdev));
          |       ^~~~~
    drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c:295:2: note: 'snprintf' output 6 or more bytes (assuming 37) into a destination of size 32
      295 |  snprintf(irq->name, MLX5_MAX_IRQ_NAME,
          |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      296 |    "%s@pci:%s", name, pci_name(dev->pdev));
          |    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: ada9f5d ("IB/mlx5: Fix eq names to display nicely in /proc/interrupts")
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d4ab2e97dcfbcd748ae71761a9d8e5e41cc732c
Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20231114215846.5902-13-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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

@@ -25,7 +25,7 @@
 struct mlx5_irq {
 	struct atomic_notifier_head nh;
 	cpumask_var_t mask;
-	char name[MLX5_MAX_IRQ_NAME];
+	char name[MLX5_MAX_IRQ_FORMATTED_NAME];
 	struct mlx5_irq_pool *pool;
 	int refcount;
 	u32 index;
@@ -236,8 +236,8 @@ struct mlx5_irq *mlx5_irq_alloc(struct mlx5_irq_pool *pool, int i,
 	else
 		irq_sf_set_name(pool, name, i);
 	ATOMIC_INIT_NOTIFIER_HEAD(&irq->nh);
-	snprintf(irq->name, MLX5_MAX_IRQ_NAME,
-		 "%s@pci:%s", name, pci_name(dev->pdev));
+	snprintf(irq->name, MLX5_MAX_IRQ_FORMATTED_NAME,
+		 MLX5_IRQ_NAME_FORMAT_STR, name, pci_name(dev->pdev));
 	err = request_irq(irq->irqn, irq_int_handler, 0, irq->name,
 			  &irq->nh);
 	if (err) {

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

@@ -7,6 +7,9 @@
 #include <linux/mlx5/driver.h>
 
 #define MLX5_MAX_IRQ_NAME (32)
+#define MLX5_IRQ_NAME_FORMAT_STR ("%s@pci:%s")
+#define MLX5_MAX_IRQ_FORMATTED_NAME \
+	(MLX5_MAX_IRQ_NAME + sizeof(MLX5_IRQ_NAME_FORMAT_STR))
 /* max irq_index is 2047, so four chars */
 #define MLX5_MAX_IRQ_IDX_CHARS (4)
 #define MLX5_EQ_REFS_PER_IRQ (2)