IB/srp: 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;
    void *entry[];
};

instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

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

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 31d9153..0f85529 100644 (file)
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -443,8 +443,7 @@ static struct srp_fr_pool *srp_create_fr_pool(struct ib_device *device,
        if (pool_size <= 0)
                goto err;
        ret = -ENOMEM;
-       pool = kzalloc(sizeof(struct srp_fr_pool) +
-                      pool_size * sizeof(struct srp_fr_desc), GFP_KERNEL);
+       pool = kzalloc(struct_size(pool, desc, pool_size), GFP_KERNEL);
        if (!pool)
                goto err;
        pool->size = pool_size;