From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:49681) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RGvKm-00055v-Du for qemu-devel@nongnu.org; Thu, 20 Oct 2011 12:19:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RGvKj-0003Os-IV for qemu-devel@nongnu.org; Thu, 20 Oct 2011 12:19:08 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:57091) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RGvKi-0003OL-Pz for qemu-devel@nongnu.org; Thu, 20 Oct 2011 12:19:05 -0400 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [202.81.31.245]) by e23smtp06.au.ibm.com (8.14.4/8.13.1) with ESMTP id p9KGHmQG004149 for ; Fri, 21 Oct 2011 03:17:48 +1100 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p9KGJ3eG1679498 for ; Fri, 21 Oct 2011 03:19:03 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p9KGJ2sE023147 for ; Fri, 21 Oct 2011 03:19:03 +1100 From: "Aneesh Kumar K.V" Date: Thu, 20 Oct 2011 21:47:40 +0530 Message-Id: <1319127460-5181-9-git-send-email-aneesh.kumar@linux.vnet.ibm.com> In-Reply-To: <1319127460-5181-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1319127460-5181-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 8/8] hw/9pfs: Replace rwlocks with RCU variants of interfaces. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: aliguori@us.ibm.com, Harsh Prateek Bora , "Aneesh Kumar K.V" From: Harsh Prateek Bora 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 Signed-off-by: Aneesh Kumar K.V --- hw/9pfs/virtio-9p-synth.c | 29 +++++++++++++---------------- 1 files changed, 13 insertions(+), 16 deletions(-) diff --git a/hw/9pfs/virtio-9p-synth.c b/hw/9pfs/virtio-9p-synth.c index 72a916c..f573616 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; @@ -60,7 +59,7 @@ static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode, } node->private = node; strncpy(node->name, name, sizeof(node->name)); - QLIST_INSERT_HEAD(&parent->child, node, sibling); + QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); return node; } @@ -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; @@ -519,11 +519,8 @@ static int v9fs_synth_unlinkat(FsContext *ctx, V9fsPath *dir, static int v9fs_synth_init(FsContext *ctx) { - 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, -- 1.7.5.4