Date: Thu, 3 Nov 2016 08:54:35 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r308246 - stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201611030854.uA38sZwV077028@repo.freebsd.org>
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Author: avg Date: Thu Nov 3 08:54:35 2016 New Revision: 308246 URL: https://svnweb.freebsd.org/changeset/base/308246 Log: MFC r307994: 3746 ZRLs are racy PR: 204037 Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zrlock.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zrlock.c ============================================================================== --- stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zrlock.c Thu Nov 3 08:54:04 2016 (r308245) +++ stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zrlock.c Thu Nov 3 08:54:35 2016 (r308246) @@ -21,6 +21,7 @@ /* * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2014, 2015 by Delphix. All rights reserved. + * Copyright 2016 The MathWorks, Inc. All rights reserved. */ /* @@ -71,37 +72,32 @@ zrl_destroy(zrlock_t *zrl) void zrl_add_impl(zrlock_t *zrl, const char *zc) { - uint32_t n = (uint32_t)zrl->zr_refcount; - - while (n != ZRL_LOCKED) { - uint32_t cas = atomic_cas_32( - (uint32_t *)&zrl->zr_refcount, n, n + 1); - if (cas == n) { - ASSERT3S((int32_t)n, >=, 0); -#ifdef ZFS_DEBUG - if (zrl->zr_owner == curthread) { - DTRACE_PROBE2(zrlock__reentry, - zrlock_t *, zrl, uint32_t, n); - } - zrl->zr_owner = curthread; - zrl->zr_caller = zc; + for (;;) { + uint32_t n = (uint32_t)zrl->zr_refcount; + while (n != ZRL_LOCKED) { + uint32_t cas = atomic_cas_32( + (uint32_t *)&zrl->zr_refcount, n, n + 1); + if (cas == n) { + ASSERT3S((int32_t)n, >=, 0); +#ifdef ZFS_DEBUG + if (zrl->zr_owner == curthread) { + DTRACE_PROBE2(zrlock__reentry, + zrlock_t *, zrl, uint32_t, n); + } + zrl->zr_owner = curthread; + zrl->zr_caller = zc; #endif - return; + return; + } + n = cas; } - n = cas; - } - mutex_enter(&zrl->zr_mtx); - while (zrl->zr_refcount == ZRL_LOCKED) { - cv_wait(&zrl->zr_cv, &zrl->zr_mtx); + mutex_enter(&zrl->zr_mtx); + while (zrl->zr_refcount == ZRL_LOCKED) { + cv_wait(&zrl->zr_cv, &zrl->zr_mtx); + } + mutex_exit(&zrl->zr_mtx); } - ASSERT3S(zrl->zr_refcount, >=, 0); - zrl->zr_refcount++; -#ifdef ZFS_DEBUG - zrl->zr_owner = curthread; - zrl->zr_caller = zc; -#endif - mutex_exit(&zrl->zr_mtx); } void
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