if (priv->dev_state < DEVICE_STATE_BOOT) {
                kfree(p);
-               if (complete_handler != NULL)
+               if (complete_handler)
                        (*complete_handler) (arg1, arg2);
                return 1;
        }
                /* in case of buffer overflow */
                DPRINTK(1, "tx buffer overflow\n");
                kfree(p);
-               if (complete_handler != NULL)
+               if (complete_handler)
                        (*complete_handler) (arg1, arg2);
                return 1;
        }
 
                }
                kfree(sp->sendp);       /* allocated memory free */
-               if (sp->complete_handler != NULL)       /* TX Complete */
+               if (sp->complete_handler)       /* TX Complete */
                        (*sp->complete_handler) (sp->arg1, sp->arg2);
                inc_txqhead(priv);
 
        while (cnt_txqbody(priv) > 0) {
                sp = &priv->tx_dev.tx_dev_buff[priv->tx_dev.qhead];
                kfree(sp->sendp);       /* allocated memory free */
-               if (sp->complete_handler != NULL)       /* TX Complete */
+               if (sp->complete_handler)       /* TX Complete */
                        (*sp->complete_handler) (sp->arg1, sp->arg2);
                inc_txqhead(priv);
        }
 
        /* private memory allocate */
        netdev = alloc_etherdev(sizeof(*priv));
-       if (netdev == NULL) {
+       if (!netdev) {
                printk(KERN_ERR "ks7010 : Unable to alloc new net device\n");
                goto error_release_irq;
        }
 
        card = sdio_get_drvdata(func);
 
-       if (card == NULL)
+       if (!card)
                return;
 
        DPRINTK(1, "priv = card->priv\n");
                        struct hostif_stop_request_t *pp;
                        pp = (struct hostif_stop_request_t *)
                            kzalloc(hif_align_size(sizeof(*pp)), GFP_KERNEL);
-                       if (pp == NULL) {
+                       if (!pp) {
                                DPRINTK(3, "allocate memory failed..\n");
                                return; /* to do goto ni suru */
                        }
 
            kmalloc(hif_align_size(sizeof(*pp) + 6 + packet_len + 8),
                    KS_WLAN_MEM_FLAG);
 
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                dev_kfree_skb(packet);
                return -2;
        /* make primitive */
        pp = (struct hostif_mib_get_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_mib_set_request_t *)
            kmalloc(hif_align_size(sizeof(*pp) + size), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_start_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_ps_adhoc_set_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_infrastructure_set_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_infrastructure_set2_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_adhoc_set_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_adhoc_set2_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_stop_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_phy_information_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_power_mngmt_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
                /* make primitive */
                pp = (struct hostif_sleep_request_t *)
                    kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-               if (pp == NULL) {
+               if (!pp) {
                        DPRINTK(3, "allocate memory failed..\n");
                        return;
                }
        /* make primitive */
        pp = (struct hostif_bss_scan_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }
        /* make primitive */
        pp = (struct hostif_mic_failure_request_t *)
            kmalloc(hif_align_size(sizeof(*pp)), KS_WLAN_MEM_FLAG);
-       if (pp == NULL) {
+       if (!pp) {
                DPRINTK(3, "allocate memory failed..\n");
                return;
        }