From owner-svn-src-head@freebsd.org Thu Jul 21 16:34:58 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5FAD0BA0E46; Thu, 21 Jul 2016 16:34:58 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 13A5C1898; Thu, 21 Jul 2016 16:34:58 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u6LGYvhn038342; Thu, 21 Jul 2016 16:34:57 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u6LGYvIH038339; Thu, 21 Jul 2016 16:34:57 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201607211634.u6LGYvIH038339@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Thu, 21 Jul 2016 16:34:57 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r303151 - in head/sys: dev/pty kern sys X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Jul 2016 16:34:58 -0000 Author: kib Date: Thu Jul 21 16:34:56 2016 New Revision: 303151 URL: https://svnweb.freebsd.org/changeset/base/303151 Log: Provide counter_warning(9) KPI which allows to issue limited number of warnings for some kernel events, mostly intended for the use of obsoleted or otherwise undersired interfaces. This is an abstracted and race-expelled code from compat pty driver. Requested and reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D7270 Modified: head/sys/dev/pty/pty.c head/sys/kern/subr_prf.c head/sys/sys/systm.h Modified: head/sys/dev/pty/pty.c ============================================================================== --- head/sys/dev/pty/pty.c Thu Jul 21 15:48:41 2016 (r303150) +++ head/sys/dev/pty/pty.c Thu Jul 21 16:34:56 2016 (r303151) @@ -52,10 +52,10 @@ __FBSDID("$FreeBSD$"); * binary emulation. */ -static unsigned int pty_warningcnt = 1; +static unsigned pty_warningcnt = 1; SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW, - &pty_warningcnt, 0, - "Warnings that will be triggered upon legacy PTY allocation"); + &pty_warningcnt, 0, + "Warnings that will be triggered upon legacy PTY allocation"); static int ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp) @@ -77,12 +77,7 @@ ptydev_fdopen(struct cdev *dev, int ffla } /* Raise a warning when a legacy PTY has been allocated. */ - if (pty_warningcnt > 0) { - pty_warningcnt--; - log(LOG_INFO, "pid %d (%s) is using legacy pty devices%s\n", - td->td_proc->p_pid, td->td_name, - pty_warningcnt ? "" : " - not logging anymore"); - } + counted_warning(&pty_warningcnt, "is using legacy pty devices"); return (0); } Modified: head/sys/kern/subr_prf.c ============================================================================== --- head/sys/kern/subr_prf.c Thu Jul 21 15:48:41 2016 (r303150) +++ head/sys/kern/subr_prf.c Thu Jul 21 16:34:56 2016 (r303151) @@ -1196,3 +1196,22 @@ sbuf_hexdump(struct sbuf *sb, const void } } +void +counted_warning(unsigned *counter, const char *msg) +{ + struct thread *td; + unsigned c; + + for (;;) { + c = *counter; + if (c == 0) + break; + if (atomic_cmpset_int(counter, c, c - 1)) { + td = curthread; + log(LOG_INFO, "pid %d (%s) %s%s\n", + td->td_proc->p_pid, td->td_name, msg, + c > 1 ? "" : " - not logging anymore"); + break; + } + } +} Modified: head/sys/sys/systm.h ============================================================================== --- head/sys/sys/systm.h Thu Jul 21 15:48:41 2016 (r303150) +++ head/sys/sys/systm.h Thu Jul 21 16:34:56 2016 (r303151) @@ -447,4 +447,6 @@ void intr_prof_stack_use(struct thread * extern void (*softdep_ast_cleanup)(void); +void counted_warning(unsigned *counter, const char *msg); + #endif /* !_SYS_SYSTM_H_ */