Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758976AbXITHKc (ORCPT ); Thu, 20 Sep 2007 03:10:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756454AbXITHFg (ORCPT ); Thu, 20 Sep 2007 03:05:36 -0400 Received: from rv-out-0910.google.com ([209.85.198.185]:65209 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755686AbXITHFb (ORCPT ); Thu, 20 Sep 2007 03:05:31 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:cc:subject:in-reply-to:x-mailer:date:message-id:mime-version:content-type:reply-to:to:content-transfer-encoding:from; b=EO32ZYfI3LfR6PpLa8F0iWTjRYWoMwIWEGE7vJYeEcYivIK6s4krwCifHHEeMQGh9E1CPX07tbk3hz/L5r+f5iapcK7p827DPdcCF+ih+Lch13ug/CCZ/m+OBHKvF+AQvxg5legSQeajfMsQbRers9rtgv+hAyleuKU32jJtxs4= Cc: Tejun Heo Subject: [PATCH 15/15] sysfs: move sysfs file poll implementation to sysfs_open_dirent In-Reply-To: <11902719091692-git-send-email-htejun@gmail.com> X-Mailer: git-send-email Date: Thu, 20 Sep 2007 16:05:12 +0900 Message-Id: <11902719121259-git-send-email-htejun@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Reply-To: Tejun Heo To: ebiederm@xmission.com, cornelia.huck@de.ibm.com, greg@kroah.com, stern@rowland.harvard.edu, kay.sievers@vrfy.org, linux-kernel@vger.kernel.org, htejun@gmail.com Content-Transfer-Encoding: 7BIT From: Tejun Heo Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4922 Lines: 156 Sysfs file poll implementation is scattered over sysfs and kobject. Event numbering is done in sysfs_dirent but wait itself is done on kobject. This not only unecessarily bloats both kobject and sysfs_dirent but is also buggy - if a sysfs_dirent is removed while there still are pollers, the associaton betwen the kobject and sysfs_dirent breaks and kobject may be freed with the pollers still sleeping on it. This patch moves whole poll implementation into sysfs_open_dirent. Each time a sysfs_open_dirent is created, event number restarts from 1 and pollers sleep on sysfs_open_dirent. As event sequence number is meaningless without any open file and pollers should have open file and thus sysfs_open_dirent, this ephemeral event counting works and is a saner implementation. This patch fixes the dnagling sleepers bug and reduces the sizes of kobject and sysfs_dirent by one pointer. Signed-off-by: Tejun Heo --- fs/sysfs/dir.c | 1 - fs/sysfs/file.c | 25 +++++++++++++++++++------ fs/sysfs/sysfs.h | 1 - include/linux/kobject.h | 1 - lib/kobject.c | 1 - 5 files changed, 19 insertions(+), 10 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index b81744b..ad3394a 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -318,7 +318,6 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type) atomic_set(&sd->s_count, 1); atomic_set(&sd->s_active, 0); - atomic_set(&sd->s_event, 1); sd->s_name = name; sd->s_mode = mode; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index b13ba94..c05f961 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -62,6 +62,8 @@ static spinlock_t sysfs_open_dirent_lock = SPIN_LOCK_UNLOCKED; struct sysfs_open_dirent { atomic_t refcnt; + atomic_t event; + wait_queue_head_t poll; struct list_head buffers; /* goes through sysfs_buffer.list */ }; @@ -104,7 +106,7 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer if (!sysfs_get_active_two(attr_sd)) return -ENODEV; - buffer->event = atomic_read(&attr_sd->s_event); + buffer->event = atomic_read(&attr_sd->s_attr.open->event); count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); sysfs_put_active_two(attr_sd); @@ -301,6 +303,8 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd, return -ENOMEM; atomic_set(&new_od->refcnt, 0); + atomic_set(&new_od->event, 1); + init_waitqueue_head(&new_od->poll); INIT_LIST_HEAD(&new_od->buffers); goto retry; } @@ -443,17 +447,17 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait) { struct sysfs_buffer * buffer = filp->private_data; struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata; - struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; + struct sysfs_open_dirent *od = attr_sd->s_attr.open; /* need parent for the kobj, grab both */ if (!sysfs_get_active_two(attr_sd)) goto trigger; - poll_wait(filp, &kobj->poll, wait); + poll_wait(filp, &od->poll, wait); sysfs_put_active_two(attr_sd); - if (buffer->event != atomic_read(&attr_sd->s_event)) + if (buffer->event != atomic_read(&od->event)) goto trigger; return 0; @@ -474,8 +478,17 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr) if (sd && attr) sd = sysfs_find_dirent(sd, attr); if (sd) { - atomic_inc(&sd->s_event); - wake_up_interruptible(&k->poll); + struct sysfs_open_dirent *od; + + spin_lock(&sysfs_open_dirent_lock); + + od = sd->s_attr.open; + if (od) { + atomic_inc(&od->event); + wake_up_interruptible(&od->poll); + } + + spin_unlock(&sysfs_open_dirent_lock); } mutex_unlock(&sysfs_mutex); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 3adce7d..269c845 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -46,7 +46,6 @@ struct sysfs_dirent { ino_t s_ino; umode_t s_mode; struct iattr *s_iattr; - atomic_t s_event; }; #define SD_DEACTIVATED_BIAS INT_MIN diff --git a/include/linux/kobject.h b/include/linux/kobject.h index 0777b3f..a8a84fc 100644 --- a/include/linux/kobject.h +++ b/include/linux/kobject.h @@ -66,7 +66,6 @@ struct kobject { struct kset * kset; struct kobj_type * ktype; struct sysfs_dirent * sd; - wait_queue_head_t poll; }; extern int kobject_set_name(struct kobject *, const char *, ...) diff --git a/lib/kobject.c b/lib/kobject.c index 01f9c3b..a280c62 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -131,7 +131,6 @@ void kobject_init(struct kobject * kobj) return; kref_init(&kobj->kref); INIT_LIST_HEAD(&kobj->entry); - init_waitqueue_head(&kobj->poll); kobj->kset = kset_get(kobj->kset); } -- 1.5.0.3 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/