problems with alloc_disk in genhd.c

[mikem@beardog.cca.cpqcorp.net]

We've encountered a problem using one of our internal test tools. It calls
our CCISS_GETLUNINFO ioctl for partition info. In the *alloc_disk(int minors)
function it only tests for the max_number_of_parts - 1.

        if (minors > 1) {
                int size = (minors - 1) * sizeof(struct hd_struct *);

When we allocate space we pass in

        for (n = 0; n < NWD; n++) {
                disk[n] = alloc_disk(1 << NWD_SHIFT);

In the  ioctl we are doing

        /* count partitions 1 to 15 with sizes > 0 */
        for(i=0; i <MAX_PART; i++) {


Depending on what lies beyond the array we have seen either Oops's or
a hard lock with a reboot about 30 seconds later. If we pass in MAX_PART - 1
we have no problems.
Is the entire disk no longer counted as partition zero?
Other drivers also pass in their max part value. Have any other problems
been reported?

Thanks,
mikem