From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762034AbXJLW5N (ORCPT ); Fri, 12 Oct 2007 18:57:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760098AbXJLWWv (ORCPT ); Fri, 12 Oct 2007 18:22:51 -0400 Received: from ns1.suse.de ([195.135.220.2]:53578 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932614AbXJLWWt (ORCPT ); Fri, 12 Oct 2007 18:22:49 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Tejun Heo , Greg Kroah-Hartman Subject: [PATCH 66/75] sysfs: move sysfs file poll implementation to sysfs_open_dirent Date: Fri, 12 Oct 2007 15:17:10 -0700 Message-Id: <11922277493627-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.5.3.4 In-Reply-To: <11922277441791-git-send-email-gregkh@suse.de> References: \<20071012221251.GB4559@kroah.com\> <11922274393667-git-send-email-gregkh@suse.de> <11922274441634-git-send-email-gregkh@suse.de> <11922274503271-git-send-email-gregkh@suse.de> <11922274543490-git-send-email-gregkh@suse.de> <11922274643370-git-send-email-gregkh@suse.de> <11922274682487-git-send-email-gregkh@suse.de> <11922274732211-git-send-email-gregkh@suse.de> <11922274772578-git-send-email-gregkh@suse.de> <1192227481691-git-send-email-gregkh@suse.de> <11922274853108-git-send-email-gregkh@suse.de> <11922274901810-git-send-email-gregkh@suse.de> <11922274941588-git-send-email-gregkh@suse.de> <11922274993462-git-send-email-gregkh@suse.de> <11922275031518-git-send-email-gregkh@suse.de> <11922275074080-git-send-email-gregkh@suse.de> <11922275121763-git-send-email-gregkh@suse.de> <11922275181138-git-send-email-gregkh@suse.de> <11922275221643-git-send-email-gregkh@suse.de> <1192227527856-git-send-email-gregkh@suse.de> <11922275312531-git-send-email-gregkh@suse.de> <11922275371856-git-send-email-gregkh@suse.de> <11922275413548-git-send-email-gregkh@suse.de> <11922275462233-git-send-email-gregkh@suse.de> <1192227551156-git-send-email-gregkh@suse.de> <11922275552558-git-send-email-gregkh@suse.de> <119222756066-git-send-email-gregkh@suse.de> <11922275642378-git-send-email-gregkh@suse.de> <11922275693989-git-send-email-gregkh@suse.de> <1192227574129-git-send-email-gregkh@suse.de> <11922275781508-git-send-email-gregkh@suse.de> <11922275843236-git-send-email-gregkh@suse.de> <1192227589276-git-send-email-gregkh@suse.de> <1192227593813-git-send-email-gregkh@suse.de> <1192227598106-git-send-email-gregkh@suse.de> <1192227603335-git-send-email-gregkh@suse.de> <1192227611369-git-send-email-gregkh@suse.de> <11922276163147-git-send-email-gregkh@suse.de> <11922276201219-git-send-email-gregkh@suse.de> <11922276254051-git-send-email-gregkh@suse.de> <11922276302338-git-send-email-gregkh@suse.de> <1192227634772-git-send-email-gregkh@suse.de> <11922276392200-git-send-email-gregkh@suse.de> <11922276433594-git-send-email-gregkh@suse.de> <11922276471365-git-send-email-gregkh@suse.de> <1192227653165-git-send-email-gregkh@suse.de> <11922276572176-git-send-email-gregkh@suse.de> <11922276622731-git-send-email-gregkh@suse.de> <11922276672660-git-send-email-gregkh@suse.de> <1192227671143-git-send-email-gregkh@suse.de> <11922276763650-git-send-email-gregkh@suse.de> <1192227681926-git-send-email-gregkh@suse.de> <11922276862914-git-send-email-gregkh@suse.de> <11922276913288-git-send-email-gregkh@suse.de> <1192227695547-git-send-email-gregkh@suse.de> <11922276993289-git-send-email-gregkh@suse.de> <11922277041450-git-send-email-gregkh@suse.de> <11922277091389-git-send-email-gregkh@suse.de> <11922277133374-git-send-email-gregkh@suse.de> <11922277181565-git-send-email-gregkh@suse.de> <11922277222714-git-send-email-gregkh@suse.de> <11922277261501-git-send-email-gregkh@suse.de> <1192227731677-git-send-email-gregkh@suse.de> <11922277364080-git-send-email-gregkh@suse.de> <11922277403355-git-send-email-gregkh@suse.de> <11922277441791-git-send-email-gregkh@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Tejun Heo 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 Acked-by: Cornelia Huck Signed-off-by: Greg Kroah-Hartman --- 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 4ad9422..e301a12 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 e8181d3..fc6db6b 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); } -- 1.5.3.4