Author: Bhumika Goyal <bhumirks@gmail.com> Some functions like kmalloc/usb_alloc_urb returns Null as their return value on failure. !x is generally preferred over x==NULL or NULL==x. So make use of !x if the value returned on failure by these functions is NULL. Done using coccinelle: @@ expression e; statement S; @@ e = \(kmalloc\|devm_kzalloc\|kmalloc_array \|devm_ioremap\|usb_alloc_urb\|alloc_netdev\)(…); – if(e==NULL) …