TPM_MINOR = 224,        /* officially assigned */
        TPM_BUFSIZE = 2048,
        TPM_NUM_DEVICES = 256,
-       TPM_NUM_MASK_ENTRIES = TPM_NUM_DEVICES / (8 * sizeof(int))
 };
 
 enum tpm_duration {
 
 static LIST_HEAD(tpm_chip_list);
 static DEFINE_SPINLOCK(driver_lock);
-static int dev_mask[TPM_NUM_MASK_ENTRIES];
+static DECLARE_BITMAP(dev_mask, TPM_NUM_DEVICES);
 
 /*
  * Array with one entry per ordinal defining the maximum amount
        sysfs_remove_group(&dev->kobj, chip->vendor.attr_group);
        tpm_bios_log_teardown(chip->bios_dir);
 
-       dev_mask[chip->dev_num / TPM_NUM_MASK_ENTRIES] &=
-           ~(1 << (chip->dev_num % TPM_NUM_MASK_ENTRIES));
+       clear_bit(chip->dev_num, dev_mask);
 
        kfree(chip);
 
 
        char *devname;
        struct tpm_chip *chip;
-       int i, j;
 
        /* Driver specific per-device data */
        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 
        memcpy(&chip->vendor, entry, sizeof(struct tpm_vendor_specific));
 
-       chip->dev_num = -1;
+       chip->dev_num = find_first_zero_bit(dev_mask, TPM_NUM_DEVICES);
 
-       for (i = 0; i < TPM_NUM_MASK_ENTRIES; i++)
-               for (j = 0; j < 8 * sizeof(int); j++)
-                       if ((dev_mask[i] & (1 << j)) == 0) {
-                               chip->dev_num =
-                                   i * TPM_NUM_MASK_ENTRIES + j;
-                               dev_mask[i] |= 1 << j;
-                               goto dev_num_search_complete;
-                       }
-
-dev_num_search_complete:
-       if (chip->dev_num < 0) {
+       if (chip->dev_num >= TPM_NUM_DEVICES) {
                dev_err(dev, "No available tpm device numbers\n");
                kfree(chip);
                return NULL;
        else
                chip->vendor.miscdev.minor = MISC_DYNAMIC_MINOR;
 
+       set_bit(chip->dev_num, dev_mask);
+
        devname = kmalloc(DEVNAME_SIZE, GFP_KERNEL);
        scnprintf(devname, DEVNAME_SIZE, "%s%d", "tpm", chip->dev_num);
        chip->vendor.miscdev.name = devname;
                        chip->vendor.miscdev.name,
                        chip->vendor.miscdev.minor);
                put_device(dev);
+               clear_bit(chip->dev_num, dev_mask);
                kfree(chip);
-               dev_mask[i] &= !(1 << j);
                return NULL;
        }