学习过《LINUX设备驱动程序》一书的请进，请教一个问题

ttjswdy

在《LINUX设备驱动程序》第十二章 块设备驱动程序中，讲到可分区设备 分区检测一节时，有以下一段代码（描述spull设备模块初始化时为分区检测所进行的适当设置）

    spull_sizes = kmalloc( (spull_devs << SPULL_SHIFT) * sizeof(int),
                          GFP_KERNEL);
    if (!spull_sizes)
        goto fail_malloc;

    /* Start with zero-sized partitions, and correctly sized units */
    memset(spull_sizes, 0, (spull_devs << SPULL_SHIFT) * sizeof(int));
    for (i=0; i< spull_devs; i++)
        spull_sizes[i<<SPULL_SHIFT] = spull_size;
    blk_size[MAJOR_NR] = spull_gendisk.sizes = spull_sizes;

    /* Allocate the partitions array. */
    spull_partitions = kmalloc( (spull_devs << SPULL_SHIFT) *
                               sizeof(struct hd_struct), GFP_KERNEL);
    if (!spull_partitions)
        goto fail_malloc;

    memset(spull_partitions, 0, (spull_devs << SPULL_SHIFT) *
           sizeof(struct hd_struct));
    /* fill in whole-disk entries */
    for (i=0; i < spull_devs; i++)
        spull_partitions[i << SPULL_SHIFT].nr_sects =
                spull_size*(blksize/SPULL_HARDSECT);
    spull_gendisk.part = spull_partitions;
    spull_gendisk.nr_real = spull_devs;
#ifndef LINUX_24
    spull_gendisk.max_nr = spull_devs;
#endif

关于这段设置spull_sizes和spull_partitions数组的代码，我有1个疑问：在这段代码内有两个for循环，分别对spull_sizes和spull_partitions数组赋值，比如说对于spull_sizes,由代码“kmalloc( (spull_devs << SPULL_SHIFT) * sizeof(int),GFP_KERNEL);”可知，spull_sizes是一个整型数组，元素为32个。（spull_devs = 2; SPULL_SHIFT = 4）。可是在FOR循环内赋值时，循环次数为2（因为spull_devs=2,即有两个spull类型的设备）,对spull_sizes数组赋值时却是用"spull_sizes[i<<SPULL_SHIFT] = spull_size;". 这样的话，岂不是只对spull_sizes[0]和spull_sizes[16]赋了值，那其他的元素呢？对spull_partitions数组的初始化也有这个疑问，不解呀~请教各位。