From owner-svn-src-stable-7@FreeBSD.ORG Tue Feb 17 21:02:36 2009 Return-Path: Delivered-To: svn-src-stable-7@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C121F10656C6; Tue, 17 Feb 2009 21:02:35 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id B69FE8FC0A; Tue, 17 Feb 2009 21:02:35 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id n1HL2ZUN027564; Tue, 17 Feb 2009 21:02:35 GMT (envelope-from jhb@svn.freebsd.org) Received: (from jhb@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id n1HL2ZZJ027560; Tue, 17 Feb 2009 21:02:35 GMT (envelope-from jhb@svn.freebsd.org) Message-Id: <200902172102.n1HL2ZZJ027560@svn.freebsd.org> From: John Baldwin Date: Tue, 17 Feb 2009 21:02:35 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org X-SVN-Group: stable-7 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r188730 - in stable/7: share/man/man9 sys sys/contrib/pf sys/dev/ath/ath_hal sys/dev/cxgb sys/kern X-BeenThere: svn-src-stable-7@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for only the 7-stable src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Feb 2009 21:02:38 -0000 Author: jhb Date: Tue Feb 17 21:02:35 2009 New Revision: 188730 URL: http://svn.freebsd.org/changeset/base/188730 Log: MFC: Permit Giant to be passed as the explicit interlock either to msleep/mtx_sleep or the various cv_*wait*() routines. Modified: stable/7/share/man/man9/ (props changed) stable/7/share/man/man9/condvar.9 stable/7/share/man/man9/sleep.9 stable/7/sys/ (props changed) stable/7/sys/contrib/pf/ (props changed) stable/7/sys/dev/ath/ath_hal/ (props changed) stable/7/sys/dev/cxgb/ (props changed) stable/7/sys/kern/kern_condvar.c stable/7/sys/kern/kern_synch.c Modified: stable/7/share/man/man9/condvar.9 ============================================================================== --- stable/7/share/man/man9/condvar.9 Tue Feb 17 20:35:11 2009 (r188729) +++ stable/7/share/man/man9/condvar.9 Tue Feb 17 21:02:35 2009 (r188730) @@ -136,9 +136,27 @@ When a thread waits on a condition, .Fa lock is atomically released before the thread is blocked, then reacquired before the function call returns. +In addition, the thread will fully drop the +.Va Giant +mutex +(even if recursed) +while the it is suspended and will reacquire the +.Va Giant +mutex before the function returns. The .Fn cv_wait_unlock function does not reacquire the lock before returning. +Note that the +.Va Giant +mutex may be specified as +.Fa lock . +However, +.Va Giant +may not be used as +.Fa lock +for the +.Fn cv_wait_unlock +function. All waiters must pass the same .Fa lock in conjunction with Modified: stable/7/share/man/man9/sleep.9 ============================================================================== --- stable/7/share/man/man9/sleep.9 Tue Feb 17 20:35:11 2009 (r188729) +++ stable/7/share/man/man9/sleep.9 Tue Feb 17 21:02:35 2009 (r188730) @@ -153,6 +153,12 @@ mutex while the thread is suspended and will reacquire the .Va Giant mutex before the function returns. +Note that the +.Va Giant +mutex may be specified as the lock to drop. +In that case, however, the +.Dv PDROP +flag is not allowed. .Pp To avoid lost wakeups, either a lock should be used to protect against races, Modified: stable/7/sys/kern/kern_condvar.c ============================================================================== --- stable/7/sys/kern/kern_condvar.c Tue Feb 17 20:35:11 2009 (r188729) +++ stable/7/sys/kern/kern_condvar.c Tue Feb 17 21:02:35 2009 (r188730) @@ -100,6 +100,7 @@ _cv_wait(struct cv *cvp, struct lock_obj int lock_state; td = curthread; + lock_state = 0; #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(1, 0); @@ -126,11 +127,13 @@ _cv_wait(struct cv *cvp, struct lock_obj DROP_GIANT(); sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_release(cvp); - lock_state = class->lc_unlock(lock); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_lock(cvp); + if (lock != &Giant.lock_object) { + if (class->lc_flags & LC_SLEEPABLE) + sleepq_release(cvp); + lock_state = class->lc_unlock(lock); + if (class->lc_flags & LC_SLEEPABLE) + sleepq_lock(cvp); + } sleepq_wait(cvp); #ifdef KTRACE @@ -138,8 +141,10 @@ _cv_wait(struct cv *cvp, struct lock_obj ktrcsw(0, 0); #endif PICKUP_GIANT(); - class->lc_lock(lock, lock_state); - WITNESS_RESTORE(lock, lock_witness); + if (lock != &Giant.lock_object) { + class->lc_lock(lock, lock_state); + WITNESS_RESTORE(lock, lock_witness); + } } /* @@ -160,6 +165,8 @@ _cv_wait_unlock(struct cv *cvp, struct l CV_ASSERT(cvp, lock, td); WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, lock, "Waiting on \"%s\"", cvp->cv_description); + KASSERT(lock != &Giant.lock_object, + ("cv_wait_unlock cannot be used with Giant")); class = LOCK_CLASS(lock); if (cold || panicstr) { @@ -210,6 +217,7 @@ _cv_wait_sig(struct cv *cvp, struct lock td = curthread; p = td->td_proc; + lock_state = 0; #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(1, 0); @@ -237,11 +245,13 @@ _cv_wait_sig(struct cv *cvp, struct lock sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR | SLEEPQ_INTERRUPTIBLE, 0); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_release(cvp); - lock_state = class->lc_unlock(lock); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_lock(cvp); + if (lock != &Giant.lock_object) { + if (class->lc_flags & LC_SLEEPABLE) + sleepq_release(cvp); + lock_state = class->lc_unlock(lock); + if (class->lc_flags & LC_SLEEPABLE) + sleepq_lock(cvp); + } rval = sleepq_wait_sig(cvp); #ifdef KTRACE @@ -249,8 +259,10 @@ _cv_wait_sig(struct cv *cvp, struct lock ktrcsw(0, 0); #endif PICKUP_GIANT(); - class->lc_lock(lock, lock_state); - WITNESS_RESTORE(lock, lock_witness); + if (lock != &Giant.lock_object) { + class->lc_lock(lock, lock_state); + WITNESS_RESTORE(lock, lock_witness); + } return (rval); } @@ -270,6 +282,7 @@ _cv_timedwait(struct cv *cvp, struct loc td = curthread; rval = 0; + lock_state = 0; #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(1, 0); @@ -297,11 +310,13 @@ _cv_timedwait(struct cv *cvp, struct loc sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR, 0); sleepq_set_timeout(cvp, timo); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_release(cvp); - lock_state = class->lc_unlock(lock); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_lock(cvp); + if (lock != &Giant.lock_object) { + if (class->lc_flags & LC_SLEEPABLE) + sleepq_release(cvp); + lock_state = class->lc_unlock(lock); + if (class->lc_flags & LC_SLEEPABLE) + sleepq_lock(cvp); + } rval = sleepq_timedwait(cvp); #ifdef KTRACE @@ -309,8 +324,10 @@ _cv_timedwait(struct cv *cvp, struct loc ktrcsw(0, 0); #endif PICKUP_GIANT(); - class->lc_lock(lock, lock_state); - WITNESS_RESTORE(lock, lock_witness); + if (lock != &Giant.lock_object) { + class->lc_lock(lock, lock_state); + WITNESS_RESTORE(lock, lock_witness); + } return (rval); } @@ -333,6 +350,7 @@ _cv_timedwait_sig(struct cv *cvp, struct td = curthread; p = td->td_proc; rval = 0; + lock_state = 0; #ifdef KTRACE if (KTRPOINT(td, KTR_CSW)) ktrcsw(1, 0); @@ -361,11 +379,13 @@ _cv_timedwait_sig(struct cv *cvp, struct sleepq_add(cvp, lock, cvp->cv_description, SLEEPQ_CONDVAR | SLEEPQ_INTERRUPTIBLE, 0); sleepq_set_timeout(cvp, timo); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_release(cvp); - lock_state = class->lc_unlock(lock); - if (class->lc_flags & LC_SLEEPABLE) - sleepq_lock(cvp); + if (lock != &Giant.lock_object) { + if (class->lc_flags & LC_SLEEPABLE) + sleepq_release(cvp); + lock_state = class->lc_unlock(lock); + if (class->lc_flags & LC_SLEEPABLE) + sleepq_lock(cvp); + } rval = sleepq_timedwait_sig(cvp); #ifdef KTRACE @@ -373,8 +393,10 @@ _cv_timedwait_sig(struct cv *cvp, struct ktrcsw(0, 0); #endif PICKUP_GIANT(); - class->lc_lock(lock, lock_state); - WITNESS_RESTORE(lock, lock_witness); + if (lock != &Giant.lock_object) { + class->lc_lock(lock, lock_state); + WITNESS_RESTORE(lock, lock_witness); + } return (rval); } Modified: stable/7/sys/kern/kern_synch.c ============================================================================== --- stable/7/sys/kern/kern_synch.c Tue Feb 17 20:35:11 2009 (r188729) +++ stable/7/sys/kern/kern_synch.c Tue Feb 17 21:02:35 2009 (r188730) @@ -139,6 +139,9 @@ _sleep(void *ident, struct lock_object * ident == &lbolt, ("sleeping without a lock")); KASSERT(p != NULL, ("msleep1")); KASSERT(ident != NULL && TD_IS_RUNNING(td), ("msleep")); + if (priority & PDROP) + KASSERT(lock != NULL && lock != &Giant.lock_object, + ("PDROP requires a non-Giant lock")); if (lock != NULL) class = LOCK_CLASS(lock); else @@ -180,7 +183,8 @@ _sleep(void *ident, struct lock_object * td->td_tid, p->p_pid, p->p_comm, wmesg, ident); DROP_GIANT(); - if (lock != NULL && !(class->lc_flags & LC_SLEEPABLE)) { + if (lock != NULL && lock != &Giant.lock_object && + !(class->lc_flags & LC_SLEEPABLE)) { WITNESS_SAVE(lock, lock_witness); lock_state = class->lc_unlock(lock); } else @@ -231,7 +235,7 @@ _sleep(void *ident, struct lock_object * ktrcsw(0, 0); #endif PICKUP_GIANT(); - if (lock != NULL && !(priority & PDROP)) { + if (lock != NULL && lock != &Giant.lock_object && !(priority & PDROP)) { class->lc_lock(lock, lock_state); WITNESS_RESTORE(lock, lock_witness); }