Copy a matrix of integers into an array

The below method copies an matrix of integers into an array of integers. You must pass to the method: the matrix (y), the number of lines(n) and columns(m) to be copied. The method returns the desired array.

    public int[] copyMatrixIntoArray(int[][] y, int n, int m) {

        int[] x = new int[n * m];

        int i = 0;
        int j = 0;
        int p = 0;

        for (i = 0; i < n; i++) {
            for (j = 0; j < m; j++) {
                x[p] = y[i][j];
                p = p + 1;
            }
        }
        return x;
    }