On Wed, Oct 16, 2024 at 03:33:40PM +0800, lizhe.67@xxxxxxxxxxxxx wrote: > >> +extern int upgrade_read(struct rw_semaphore *sem); > > > >No need for the extern. Also please make any new advanced funtionality > > Sorry I don't understand why extern is not needed. If we remove it, > we will encounter the following compilation error: That sounds like you dropped the entire line above, and not just the "extern ".
