Commit 196d7311 authored Feb 07, 2019 by Gustavo A. R. Silva Committed by David S. Miller Feb 08, 2019

igc: Use struct_size() helper



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 = kzalloc(size, 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)

Notice that, in this case, variable 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>

parent a0feac18

drivers/net/ethernet/intel/igc/igc_main.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -2958,22 +2958,21 @@ static int igc_alloc_q_vector(struct igc_adapter *adapter,
		{
		struct igc_q_vector *q_vector;
		struct igc_ring *ring;
		int ring_count, size;
		int ring_count;

		/* igc only supports 1 Tx and/or 1 Rx queue per vector */
		if (txr_count > 1 \|\| rxr_count > 1)
		return -ENOMEM;

		ring_count = txr_count + rxr_count;
		size = sizeof(struct igc_q_vector) +
		(sizeof(struct igc_ring) * ring_count);

		/* allocate q_vector and rings */
		q_vector = adapter->q_vector[v_idx];
		if (!q_vector)
		q_vector = kzalloc(size, GFP_KERNEL);
		q_vector = kzalloc(struct_size(q_vector, ring, ring_count),
		GFP_KERNEL);
		else
		memset(q_vector, 0, size);
		memset(q_vector, 0, struct_size(q_vector, ring, ring_count));
		if (!q_vector)
		return -ENOMEM;

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