[tip: irq/core] irqchip/bcm-6345-l1: Prefer struct_size)_ over open coded arithmetic

["tip-bot2 for Erick Archer" <tip-bot2@linutronix.de>]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     004c7a6bf43edbd4b092fb6ebba8991d56bc3428
Gitweb:        https://git.kernel.org/tip/004c7a6bf43edbd4b092fb6ebba8991d56bc3428
Author:        Erick Archer <erick.archer@gmx.com>
AuthorDate:    Fri, 09 Feb 2024 19:16:00 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 13 Feb 2024 10:53:15 +01:00

irqchip/bcm-6345-l1: Prefer struct_size)_ over open coded arithmetic

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows.

The cpu variable is a pointer to "struct bcm6345_l1_cpu" and this structure
ends in a flexible array:

struct bcm6345_l1_cpu {
	[...]
	u32	enable_cache[];
};

The preferred way in the kernel is to use the struct_size() helper to do
the arithmetic instead of the argument "size + count * size" in the
kzalloc() function.

This way, the code is more readable and safer.

Signed-off-by: Erick Archer <erick.archer@gmx.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20240209181600.9472-1-erick.archer@gmx.com
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Link: https://github.com/KSPP/linux/issues/162 [2]

---
 drivers/irqchip/irq-bcm6345-l1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-bcm6345-l1.c b/drivers/irqchip/irq-bcm6345-l1.c
index 9745a11..eb02d20 100644
--- a/drivers/irqchip/irq-bcm6345-l1.c
+++ b/drivers/irqchip/irq-bcm6345-l1.c
@@ -242,7 +242,7 @@ static int __init bcm6345_l1_init_one(struct device_node *dn,
 	else if (intc->n_words != n_words)
 		return -EINVAL;
 
-	cpu = intc->cpus[idx] = kzalloc(sizeof(*cpu) + n_words * sizeof(u32),
+	cpu = intc->cpus[idx] = kzalloc(struct_size(cpu, enable_cache, n_words),
 					GFP_KERNEL);
 	if (!cpu)
 		return -ENOMEM;