Re: [RFC 1/1] eventpoll: support busy poll per epoll instance

[kernel test robot <lkp@intel.com>]

Hi Joe,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on perf-tools-next/perf-tools-next]
[also build test ERROR on tip/perf/core perf-tools/perf-tools linus/master horms-ipvs/master acme/perf/core v6.7 next-20240119]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Joe-Damato/eventpoll-support-busy-poll-per-epoll-instance/20240120-084514
base:   https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git perf-tools-next
patch link:    https://lore.kernel.org/r/20240120004247.42036-2-jdamato%40fastly.com
patch subject: [RFC 1/1] eventpoll: support busy poll per epoll instance
config: i386-buildonly-randconfig-006-20240121 (https://download.01.org/0day-ci/archive/20240121/202401212307.5cz428Nn-lkp@intel.com/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240121/202401212307.5cz428Nn-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401212307.5cz428Nn-lkp@intel.com/

All errors (new ones prefixed by >>):

   fs/fcntl.c: In function 'do_fcntl':
>> fs/fcntl.c:425:9: error: implicit declaration of function 'eventpoll_fcntl'; did you mean 'eventpoll_release'? [-Werror=implicit-function-declaration]
      err = eventpoll_fcntl(filp, cmd, arg);
            ^~~~~~~~~~~~~~~
            eventpoll_release
   cc1: some warnings being treated as errors


vim +425 fs/fcntl.c

   316	
   317	static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
   318			struct file *filp)
   319	{
   320		void __user *argp = (void __user *)arg;
   321		int argi = (int)arg;
   322		struct flock flock;
   323		long err = -EINVAL;
   324	
   325		switch (cmd) {
   326		case F_DUPFD:
   327			err = f_dupfd(argi, filp, 0);
   328			break;
   329		case F_DUPFD_CLOEXEC:
   330			err = f_dupfd(argi, filp, O_CLOEXEC);
   331			break;
   332		case F_GETFD:
   333			err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
   334			break;
   335		case F_SETFD:
   336			err = 0;
   337			set_close_on_exec(fd, argi & FD_CLOEXEC);
   338			break;
   339		case F_GETFL:
   340			err = filp->f_flags;
   341			break;
   342		case F_SETFL:
   343			err = setfl(fd, filp, argi);
   344			break;
   345	#if BITS_PER_LONG != 32
   346		/* 32-bit arches must use fcntl64() */
   347		case F_OFD_GETLK:
   348	#endif
   349		case F_GETLK:
   350			if (copy_from_user(&flock, argp, sizeof(flock)))
   351				return -EFAULT;
   352			err = fcntl_getlk(filp, cmd, &flock);
   353			if (!err && copy_to_user(argp, &flock, sizeof(flock)))
   354				return -EFAULT;
   355			break;
   356	#if BITS_PER_LONG != 32
   357		/* 32-bit arches must use fcntl64() */
   358		case F_OFD_SETLK:
   359		case F_OFD_SETLKW:
   360			fallthrough;
   361	#endif
   362		case F_SETLK:
   363		case F_SETLKW:
   364			if (copy_from_user(&flock, argp, sizeof(flock)))
   365				return -EFAULT;
   366			err = fcntl_setlk(fd, filp, cmd, &flock);
   367			break;
   368		case F_GETOWN:
   369			/*
   370			 * XXX If f_owner is a process group, the
   371			 * negative return value will get converted
   372			 * into an error.  Oops.  If we keep the
   373			 * current syscall conventions, the only way
   374			 * to fix this will be in libc.
   375			 */
   376			err = f_getown(filp);
   377			force_successful_syscall_return();
   378			break;
   379		case F_SETOWN:
   380			err = f_setown(filp, argi, 1);
   381			break;
   382		case F_GETOWN_EX:
   383			err = f_getown_ex(filp, arg);
   384			break;
   385		case F_SETOWN_EX:
   386			err = f_setown_ex(filp, arg);
   387			break;
   388		case F_GETOWNER_UIDS:
   389			err = f_getowner_uids(filp, arg);
   390			break;
   391		case F_GETSIG:
   392			err = filp->f_owner.signum;
   393			break;
   394		case F_SETSIG:
   395			/* arg == 0 restores default behaviour. */
   396			if (!valid_signal(argi)) {
   397				break;
   398			}
   399			err = 0;
   400			filp->f_owner.signum = argi;
   401			break;
   402		case F_GETLEASE:
   403			err = fcntl_getlease(filp);
   404			break;
   405		case F_SETLEASE:
   406			err = fcntl_setlease(fd, filp, argi);
   407			break;
   408		case F_NOTIFY:
   409			err = fcntl_dirnotify(fd, filp, argi);
   410			break;
   411		case F_SETPIPE_SZ:
   412		case F_GETPIPE_SZ:
   413			err = pipe_fcntl(filp, cmd, argi);
   414			break;
   415		case F_ADD_SEALS:
   416		case F_GET_SEALS:
   417			err = memfd_fcntl(filp, cmd, argi);
   418			break;
   419		case F_GET_RW_HINT:
   420		case F_SET_RW_HINT:
   421			err = fcntl_rw_hint(filp, cmd, arg);
   422			break;
   423		case F_EPOLL_GET_BUSY_POLL_USECS:
   424		case F_EPOLL_SET_BUSY_POLL_USECS:
 > 425			err = eventpoll_fcntl(filp, cmd, arg);
   426			break;
   427		default:
   428			break;
   429		}
   430		return err;
   431	}
   432	

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