wan: wanxl: use struct_size() in kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
    int stuff;
    struct boo entry[];
};

size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)

Notice that, in this case, variable alloc_size is not necessary, hence
it is removed.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wan/wanxl.c b/drivers/net/wan/wanxl.c
index d573a57..459ce52 100644 (file)
--- a/drivers/net/wan/wanxl.c
+++ b/drivers/net/wan/wanxl.c
@@ -565,7 +565,7 @@ static int wanxl_pci_init_one(struct pci_dev *pdev,
        u32 plx_phy;            /* PLX PCI base address */
        u32 mem_phy;            /* memory PCI base addr */
        u8 __iomem *mem;        /* memory virtual base addr */
-       int i, ports, alloc_size;
+       int i, ports;
 
 #ifndef MODULE
        pr_info_once("%s\n", version);
@@ -601,8 +601,7 @@ static int wanxl_pci_init_one(struct pci_dev *pdev,
        default: ports = 4;
        }
 
-       alloc_size = sizeof(struct card) + ports * sizeof(struct port);
-       card = kzalloc(alloc_size, GFP_KERNEL);
+       card = kzalloc(struct_size(card, ports, ports), GFP_KERNEL);
        if (card == NULL) {
                pci_release_regions(pdev);
                pci_disable_device(pdev);