if (ncci == 0xffffffff || np->ncci == ncci) {
                        *pp = (*pp)->next;
 #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
-                       if ((mp = np->minorp) != 0) {
+                       if ((mp = np->minorp) != NULL) {
 #if defined(CONFIG_ISDN_CAPI_CAPIFS) || defined(CONFIG_ISDN_CAPI_CAPIFS_MODULE)
                                capifs_free_ncci(mp->minor);
 #endif
                        }
 #endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
                        kfree(np);
-                       if (*pp == 0) return;
+                       if (*pp == NULL) return;
                } else {
                        pp = &(*pp)->next;
                }
 #endif
                goto bad;
        }
-       if ((nskb = gen_data_b3_resp_for(mp, skb)) == 0) {
+       if ((nskb = gen_data_b3_resp_for(mp, skb)) == NULL) {
                printk(KERN_ERR "capi: gen_data_b3_resp failed\n");
                goto bad;
        }
 static void handle_minor_recv(struct capiminor *mp)
 {
        struct sk_buff *skb;
-       while ((skb = skb_dequeue(&mp->inqueue)) != 0) {
+       while ((skb = skb_dequeue(&mp->inqueue)) != NULL) {
                unsigned int len = skb->len;
                mp->inbytes -= len;
                if (handle_recv_skb(mp, skb) < 0) {
                return 0;
        }
 
-       while ((skb = skb_dequeue(&mp->outqueue)) != 0) {
+       while ((skb = skb_dequeue(&mp->outqueue)) != NULL) {
                datahandle = mp->datahandle;
                len = (u16)skb->len;
                skb_push(skb, CAPI_DATA_B3_REQ_LEN);
        if (!cdev->ap.applid)
                return -ENODEV;
 
-       if ((skb = skb_dequeue(&cdev->recvqueue)) == 0) {
+       if ((skb = skb_dequeue(&cdev->recvqueue)) == NULL) {
 
                if (file->f_flags & O_NONBLOCK)
                        return -EAGAIN;
 
                for (;;) {
                        interruptible_sleep_on(&cdev->recvwait);
-                       if ((skb = skb_dequeue(&cdev->recvqueue)) != 0)
+                       if ((skb = skb_dequeue(&cdev->recvqueue)) != NULL)
                                break;
                        if (signal_pending(current))
                                break;
                }
-               if (skb == 0)
+               if (skb == NULL)
                        return -ERESTARTNOHAND;
        }
        if (skb->len > count) {
                                return -EFAULT;
 
                        mutex_lock(&cdev->ncci_list_mtx);
-                       if ((nccip = capincci_find(cdev, (u32) ncci)) == 0) {
+                       if ((nccip = capincci_find(cdev, (u32) ncci)) == NULL) {
                                mutex_unlock(&cdev->ncci_list_mtx);
                                return 0;
                        }
 #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
-                       if ((mp = nccip->minorp) != 0) {
+                       if ((mp = nccip->minorp) != NULL) {
                                count += atomic_read(&mp->ttyopencount);
                        }
 #endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
                                return -EFAULT;
                        mutex_lock(&cdev->ncci_list_mtx);
                        nccip = capincci_find(cdev, (u32) ncci);
-                       if (!nccip || (mp = nccip->minorp) == 0) {
+                       if (!nccip || (mp = nccip->minorp) == NULL) {
                                mutex_unlock(&cdev->ncci_list_mtx);
                                return -ESRCH;
                        }
        if (file->private_data)
                return -EEXIST;
 
-       if ((file->private_data = capidev_alloc()) == 0)
+       if ((file->private_data = capidev_alloc()) == NULL)
                return -ENOMEM;
 
        return nonseekable_open(inode, file);
        struct capiminor *mp;
        unsigned long flags;
 
-       if ((mp = capiminor_find(iminor(file->f_path.dentry->d_inode))) == 0)
+       if ((mp = capiminor_find(iminor(file->f_path.dentry->d_inode))) == NULL)
                return -ENXIO;
-       if (mp->nccip == 0)
+       if (mp->nccip == NULL)
                return -ENXIO;
 
        tty->driver_data = (void *)mp;
 #ifdef _DEBUG_REFCOUNT
                printk(KERN_DEBUG "capinc_tty_close ocount=%d\n", atomic_read(&mp->ttyopencount));
 #endif
-               if (mp->nccip == 0)
+               if (mp->nccip == NULL)
                        capiminor_free(mp);
        }
 
        char *compileinfo;
        int major_ret;
 
-       if ((p = strchr(revision, ':')) != 0 && p[1]) {
+       if ((p = strchr(revision, ':')) != NULL && p[1]) {
                strlcpy(rev, p + 2, sizeof(rev));
-               if ((p = strchr(rev, '$')) != 0 && p > rev)
+               if ((p = strchr(rev, '$')) != NULL && p > rev)
                   *(p-1) = 0;
        } else
                strcpy(rev, "1.0");
 
 
        plcip = kzalloc(sizeof(capidrv_plci), GFP_ATOMIC);
 
-       if (plcip == 0)
+       if (plcip == NULL)
                return NULL;
 
        plcip->state = ST_PLCI_NONE;
 
        nccip = kzalloc(sizeof(capidrv_ncci), GFP_ATOMIC);
 
-       if (nccip == 0)
+       if (nccip == NULL)
                return NULL;
 
        nccip->ncci = ncci;
        capidrv_plci *plcip;
        capidrv_ncci *p;
 
-       if ((plcip = find_plci_by_ncci(card, ncci)) == 0)
+       if ((plcip = find_plci_by_ncci(card, ncci)) == NULL)
                return NULL;
 
        for (p = plcip->ncci_list; p; p = p->next)
        capidrv_plci *plcip;
        capidrv_ncci *p;
 
-       if ((plcip = find_plci_by_ncci(card, ncci)) == 0)
+       if ((plcip = find_plci_by_ncci(card, ncci)) == NULL)
                return NULL;
 
        for (p = plcip->ncci_list; p; p = p->next)
 {
        int i;
        for (i = 0; i < card->nbchan; i++) {
-               if (card->bchans[i].plcip == 0) {
+               if (card->bchans[i].plcip == NULL) {
                        card->bchans[i].disconnecting = 0;
                        return i;
                }
                return;
        }
        bchan = &card->bchans[chan];
-       if ((plcip = new_plci(card, chan)) == 0) {
+       if ((plcip = new_plci(card, chan)) == NULL) {
                printk(KERN_ERR "capidrv-%d: incoming call: no memory, sorry.\n", card->contrnr);
                return;
        }
                                              NULL,     /* Useruserdata */
                                              NULL      /* Facilitydataarray */
                            );
-                       if ((plcip = new_plci(card, (c->arg % card->nbchan))) == 0) {
+                       if ((plcip = new_plci(card, (c->arg % card->nbchan))) == NULL) {
                                cmd.command = ISDN_STAT_DHUP;
                                cmd.driver = card->myid;
                                cmd.arg = (c->arg % card->nbchan);
                        card->name, errcode);
           return;
        }
-       if (strstr(manufacturer, "AVM") == 0) {
+       if (strstr(manufacturer, "AVM") == NULL) {
           printk(KERN_ERR "%s: not from AVM, no d-channel trace possible (%s)\n",
                        card->name, manufacturer);
           return;
        u32 ncontr, contr;
        u16 errcode;
 
-       if ((p = strchr(revision, ':')) != 0 && p[1]) {
+       if ((p = strchr(revision, ':')) != NULL && p[1]) {
                strncpy(rev, p + 2, sizeof(rev));
                rev[sizeof(rev)-1] = 0;
-               if ((p = strchr(rev, '$')) != 0 && p > rev)
+               if ((p = strchr(rev, '$')) != NULL && p > rev)
                   *(p-1) = 0;
        } else
                strcpy(rev, "1.0");
        char rev[32];
        char *p;
 
-       if ((p = strchr(revision, ':')) != 0) {
+       if ((p = strchr(revision, ':')) != NULL) {
                strncpy(rev, p + 1, sizeof(rev));
                rev[sizeof(rev)-1] = 0;
-               if ((p = strchr(rev, '$')) != 0)
+               if ((p = strchr(rev, '$')) != NULL)
                        *p = 0;
        } else {
                strcpy(rev, " ??? ");
 
        char *p;
        int err;
 
-       if ((p = strchr(revision, ':')) != 0 && p[1]) {
+       if ((p = strchr(revision, ':')) != NULL && p[1]) {
                strlcpy(rev, p + 2, sizeof(rev));
-               if ((p = strchr(rev, '$')) != 0 && p > rev)
+               if ((p = strchr(rev, '$')) != NULL && p > rev)
                   *(p-1) = 0;
        } else
                strcpy(rev, "1.0");
 
 static inline int mq_enqueue(struct capilib_ncci * np, u16 msgid)
 {
        struct capilib_msgidqueue *mq;
-       if ((mq = np->msgidfree) == 0)
+       if ((mq = np->msgidfree) == NULL)
                return 0;
        np->msgidfree = mq->next;
        mq->msgid = msgid;
 
                        cmsg->l += 4;
                        break;
                case _CSTRUCT:
-                       if (*(u8 **) OFF == 0) {
+                       if (*(u8 **) OFF == NULL) {
                                *(cmsg->m + cmsg->l) = '\0';
                                cmsg->l++;
                        } else if (**(_cstruct *) OFF != 0xff) {
 
                card = capi_ctr_get(card);
                if (!card)
                        return -ESRCH;
-               if (card->load_firmware == 0) {
+               if (card->load_firmware == NULL) {
                        printk(KERN_DEBUG "kcapi: load: no load function\n");
                        return -ESRCH;
                }
                        printk(KERN_DEBUG "kcapi: load: invalid parameter: length of t4file is %d ?\n", ldef.t4file.len);
                        return -EINVAL;
                }
-               if (ldef.t4file.data == 0) {
+               if (ldef.t4file.data == NULL) {
                        printk(KERN_DEBUG "kcapi: load: invalid parameter: dataptr is 0\n");
                        return -EINVAL;
                }
                        if (strcmp(driver->name, cdef.driver) == 0)
                                break;
                }
-               if (driver == 0) {
+               if (driver == NULL) {
                        printk(KERN_ERR "kcapi: driver \"%s\" not loaded.\n",
                                        cdef.driver);
                        return -ESRCH;
                return ret;
         kcapi_proc_init();
 
-       if ((p = strchr(revision, ':')) != 0 && p[1]) {
+       if ((p = strchr(revision, ':')) != NULL && p[1]) {
                strlcpy(rev, p + 2, sizeof(rev));
-               if ((p = strchr(rev, '$')) != 0 && p > rev)
+               if ((p = strchr(rev, '$')) != NULL && p > rev)
                   *(p-1) = 0;
        } else
                strcpy(rev, "1.0");