error = 0;
                        /* Check for command packet errors */
                        if (full_command_packet->command.newcommand.status != 0) {
-                               if (tw_dev->srb[request_id] != 0) {
+                               if (tw_dev->srb[request_id] != NULL) {
                                        error = twa_fill_sense(tw_dev, request_id, 1, 1);
                                } else {
                                        /* Skip ioctl error prints */
 
                        /* Check for correct state */
                        if (tw_dev->state[request_id] != TW_S_POSTED) {
-                               if (tw_dev->srb[request_id] != 0) {
+                               if (tw_dev->srb[request_id] != NULL) {
                                        TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1a, "Received a request id that wasn't posted");
                                        TW_CLEAR_ALL_INTERRUPTS(tw_dev);
                                        goto twa_interrupt_bail;
                        }
 
                        /* Check for internal command completion */
-                       if (tw_dev->srb[request_id] == 0) {
+                       if (tw_dev->srb[request_id] == NULL) {
                                if (request_id != tw_dev->chrdev_request_id) {
                                        if (twa_aen_complete(tw_dev, request_id))
                                                TW_PRINTK(tw_dev->host, TW_DRIVER, 0x1b, "Error completing AEN during attention interrupt");
 
        if (i == ARRAY_SIZE(ports))
                return 0;
 
-       if ( request_region(setup->io_port, IO_RANGE, "aha152x")==0 ) {
+       if (!request_region(setup->io_port, IO_RANGE, "aha152x")) {
                printk(KERN_ERR "aha152x: io port 0x%x busy.\n", setup->io_port);
                return 0;
        }
                        if ((setup_count == 1) && (setup[0].io_port == ports[i]))
                                continue;
 
-                       if ( request_region(ports[i], IO_RANGE, "aha152x")==0 ) {
+                       if (!request_region(ports[i], IO_RANGE, "aha152x")) {
                                printk(KERN_ERR "aha152x: io port 0x%x busy.\n", ports[i]);
                                continue;
                        }
 
                dev->quhd[c] = 0;
        }
        workreq = dev->quereq[c][dev->quhd[c]];
-       if (dev->id[c][scmd_id(workreq)].curr_req == 0) {       
+       if (dev->id[c][scmd_id(workreq)].curr_req == NULL) {
                dev->id[c][scmd_id(workreq)].curr_req = workreq;
                dev->last_cmd[c] = scmd_id(workreq);
                goto cmd_subp;
 
        if (!(pci_resource_flags(pcidev, index) & IORESOURCE_MEM)) {
                printk(KERN_ERR "scsi%d: pci resource invalid\n",
                                hba->host->host_no);
-               return 0;
+               return NULL;
        }
 
        mem_base_phy = pci_resource_start(pcidev, index);
        if (!mem_base_virt) {
                printk(KERN_ERR "scsi%d: Fail to ioremap memory space\n",
                                hba->host->host_no);
-               return 0;
+               return NULL;
        }
        return mem_base_virt;
 }
 static int hptiop_map_pci_bar_mv(struct hptiop_hba *hba)
 {
        hba->u.mv.regs = hptiop_map_pci_bar(hba, 0);
-       if (hba->u.mv.regs == 0)
+       if (hba->u.mv.regs == NULL)
                return -1;
 
        hba->u.mv.mu = hptiop_map_pci_bar(hba, 2);
-       if (hba->u.mv.mu == 0) {
+       if (hba->u.mv.mu == NULL) {
                iounmap(hba->u.mv.regs);
                return -1;
        }
 
 static struct hptiop_adapter_ops hptiop_itl_ops = {
        .iop_wait_ready    = iop_wait_ready_itl,
-       .internal_memalloc = 0,
-       .internal_memfree  = 0,
+       .internal_memalloc = NULL,
+       .internal_memfree  = NULL,
        .map_pci_bar       = hptiop_map_pci_bar_itl,
        .unmap_pci_bar     = hptiop_unmap_pci_bar_itl,
        .enable_intr       = hptiop_enable_intr_itl,
 
 
        /* Check for room in outstanding command list. */
        for (cnt = 0; cnt < MAX_OUTSTANDING_COMMANDS &&
-                    ha->outstanding_cmds[cnt] != 0; cnt++);
+                    ha->outstanding_cmds[cnt] != NULL; cnt++);
 
        if (cnt >= MAX_OUTSTANDING_COMMANDS) {
                status = 1;