From patchwork Thu Oct 13 20:35:02 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Harsh Prateek Bora X-Patchwork-Id: 119608 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 67EAFB70C0 for ; Fri, 14 Oct 2011 07:35:43 +1100 (EST) Received: from localhost ([::1]:54343 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RERzz-0006si-6Q for incoming@patchwork.ozlabs.org; Thu, 13 Oct 2011 16:35:27 -0400 Received: from eggs.gnu.org ([140.186.70.92]:41072) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RERzp-0006fe-GB for qemu-devel@nongnu.org; Thu, 13 Oct 2011 16:35:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RERzo-0007aH-FF for qemu-devel@nongnu.org; Thu, 13 Oct 2011 16:35:17 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:37577) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RERzn-0007YS-Jp for qemu-devel@nongnu.org; Thu, 13 Oct 2011 16:35:16 -0400 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by e28smtp04.in.ibm.com (8.14.4/8.13.1) with ESMTP id p9DKZ7tS021226 for ; Fri, 14 Oct 2011 02:05:07 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p9DKZ7Gl4571198 for ; Fri, 14 Oct 2011 02:05:07 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p9DKZ7xE023107 for ; Fri, 14 Oct 2011 02:05:07 +0530 Received: from harshbora.in.ibm.com ([9.77.195.160]) by d28av01.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id p9DKZ50Q022942; Fri, 14 Oct 2011 02:05:06 +0530 From: Harsh Prateek Bora To: qemu-devel@nongnu.org Date: Fri, 14 Oct 2011 02:05:02 +0530 Message-Id: <1318538102-6982-2-git-send-email-harsh@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1.1 In-Reply-To: <1318538102-6982-1-git-send-email-harsh@linux.vnet.ibm.com> References: <1318538102-6982-1-git-send-email-harsh@linux.vnet.ibm.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 122.248.162.4 Cc: pbonzini@redhat.com, jan.kiszka@web.de, aneesh.kumar@linux.vnet.ibm.com Subject: [Qemu-devel] [PATCH v2 2/2] Replace rwlocks with RCU variants of interfaces. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Use QLIST_INSERT_HEAD_RCU and rcu_read_lock/unlock instead of rwlocks. Use v9fs_synth_mutex as a write-only mutex to handle concurrent writers. Signed-off-by: Harsh Prateek Bora --- hw/9pfs/virtio-9p-synth.c | 26 ++++++++++++-------------- 1 files changed, 12 insertions(+), 14 deletions(-) diff --git a/hw/9pfs/virtio-9p-synth.c b/hw/9pfs/virtio-9p-synth.c index cbf74e4..567611e 100644 --- a/hw/9pfs/virtio-9p-synth.c +++ b/hw/9pfs/virtio-9p-synth.c @@ -30,8 +30,7 @@ V9fsSynthNode v9fs_synth_root = { .attr = &v9fs_synth_root.actual_attr, }; -/*FIXME!! should be converted to qemu_rwlock_t */ -static pthread_rwlock_t v9fs_synth_mutex; +static QemuMutex v9fs_synth_mutex; static int v9fs_synth_node_count; /* set to 1 when the synth fs is ready */ static int v9fs_synth_fs; @@ -79,7 +78,7 @@ int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, if (!parent) { parent = &v9fs_synth_root; } - pthread_rwlock_wrlock(&v9fs_synth_mutex); + qemu_mutex_lock(&v9fs_synth_mutex); QLIST_FOREACH(tmp, &parent->child, sibling) { if (!strcmp(tmp->name, name)) { ret = EEXIST; @@ -95,7 +94,7 @@ int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, *result = node; ret = 0; err_out: - pthread_rwlock_unlock(&v9fs_synth_mutex); + qemu_mutex_unlock(&v9fs_synth_mutex); return ret; } @@ -116,7 +115,7 @@ int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode, parent = &v9fs_synth_root; } - pthread_rwlock_wrlock(&v9fs_synth_mutex); + qemu_mutex_lock(&v9fs_synth_mutex); QLIST_FOREACH(tmp, &parent->child, sibling) { if (!strcmp(tmp->name, name)) { ret = EEXIST; @@ -134,10 +133,10 @@ int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode, node->attr->mode = mode; node->private = arg; strncpy(node->name, name, sizeof(node->name)); - QLIST_INSERT_HEAD(&parent->child, node, sibling); + QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); ret = 0; err_out: - pthread_rwlock_unlock(&v9fs_synth_mutex); + qemu_mutex_unlock(&v9fs_synth_mutex); return ret; } @@ -230,7 +229,7 @@ static int v9fs_synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry, int i = 0; V9fsSynthNode *node; - pthread_rwlock_rdlock(&v9fs_synth_mutex); + rcu_read_lock(); QLIST_FOREACH(node, &dir->child, sibling) { /* This is the off child of the directory */ if (i == off) { @@ -238,7 +237,7 @@ static int v9fs_synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry, } i++; } - pthread_rwlock_unlock(&v9fs_synth_mutex); + rcu_read_unlock(); if (!node) { /* end of directory */ *result = NULL; @@ -483,13 +482,14 @@ static int v9fs_synth_name_to_path(FsContext *ctx, V9fsPath *dir_path, goto out; } /* search for the name in the childern */ - pthread_rwlock_rdlock(&v9fs_synth_mutex); + rcu_read_lock(); QLIST_FOREACH(node, &dir_node->child, sibling) { if (!strcmp(node->name, name)) { break; } } - pthread_rwlock_unlock(&v9fs_synth_mutex); + rcu_read_unlock(); + if (!node) { errno = ENOENT; return -1; @@ -532,11 +532,9 @@ static ssize_t my_test_read(void *in_buf, int len, off_t offset, void *arg) static int v9fs_synth_init(FsContext *ctx) { V9fsSynthNode *node; - pthread_rwlockattr_t rwlockattr; QLIST_INIT(&v9fs_synth_root.child); - pthread_rwlockattr_init(&rwlockattr); - pthread_rwlock_init(&v9fs_synth_mutex, &rwlockattr); + qemu_mutex_init(&v9fs_synth_mutex); /* Add "." and ".." entries for root */ v9fs_add_dir_node(&v9fs_synth_root, v9fs_synth_root.attr->mode,