Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762975AbXE1Qh1 (ORCPT ); Mon, 28 May 2007 12:37:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757738AbXE1Qgi (ORCPT ); Mon, 28 May 2007 12:36:38 -0400 Received: from py-out-1112.google.com ([64.233.166.178]:61264 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152AbXE1Qge (ORCPT ); Mon, 28 May 2007 12:36:34 -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=drku0PQYEzs+KJYpfJkPyabArOPxTwU/qyyUo0QdwbcQlzT4box2E4WUAitWW81KtPmnfbG+ATXnaZfPi2Bx1F5bd+L5FofFcErdWNOl8pDCtZsN/sokqCc+dbrzFe9dwtM8oJC8y5QwetrXh/c+GTsnsYdPBJm4RNiF5JGnNew= Cc: Tejun Heo Subject: [PATCH 4/6] sysfs: use sysfs_lock to protect the sysfs_dirent tree In-Reply-To: <11803701861778-git-send-email-htejun@gmail.com> X-Mailer: git-send-email Date: Tue, 29 May 2007 01:36:27 +0900 Message-Id: <1180370187803-git-send-email-htejun@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Reply-To: Tejun Heo To: gregkh@suse.de, dmitry.torokhov@gmail.com, cornelia.huck@de.ibm.com, oneukum@suse.de, rpurdie@rpsys.net, stern@rowland.harvard.edu, maneesh@in.ibm.com, 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: 14524 Lines: 551 As kobj sysfs dentries and inodes are gonna be made reclaimable, i_mutex can't be used to protect sysfs_dirent tree. Use sysfs_lock instead. Signed-off-by: Tejun Heo --- fs/sysfs/dir.c | 107 ++++++++++++++++++++++++++++++++++----------------- fs/sysfs/file.c | 31 +++++++-------- fs/sysfs/inode.c | 9 +--- fs/sysfs/symlink.c | 51 +++++++++++++------------ fs/sysfs/sysfs.h | 1 - 5 files changed, 115 insertions(+), 84 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 58a92aa..a474e54 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -14,7 +14,6 @@ #include #include "sysfs.h" -DECLARE_RWSEM(sysfs_rename_sem); spinlock_t sysfs_lock = SPIN_LOCK_UNLOCKED; spinlock_t kobj_sysfs_assoc_lock = SPIN_LOCK_UNLOCKED; @@ -29,7 +28,7 @@ static DEFINE_IDA(sysfs_ino_ida); * sd->s_parent->s_children. * * Locking: - * mutex_lock(sd->s_parent->dentry->d_inode->i_mutex) + * spin_lock(sysfs_lock) */ static void sysfs_link_sibling(struct sysfs_dirent *sd) { @@ -48,7 +47,7 @@ static void sysfs_link_sibling(struct sy * sd->s_parent->s_children. * * Locking: - * mutex_lock(sd->s_parent->dentry->d_inode->i_mutex) + * spin_lock(sysfs_lock) */ static void sysfs_unlink_sibling(struct sysfs_dirent *sd) { @@ -216,6 +215,9 @@ void release_sysfs_dirent(struct sysfs_d struct sysfs_dirent *parent_sd; repeat: + /* Moving/renaming is always done while holding reference. + * sd->s_parent won't change beneath us. + */ parent_sd = sd->s_parent; if (sysfs_type(sd) & SYSFS_KOBJ_LINK) @@ -292,19 +294,36 @@ struct sysfs_dirent *sysfs_new_dirent(co return NULL; } +/** + * sysfs_attach_dentry - associate sysfs_dirent with dentry + * @sd: target sysfs_dirent + * @dentry: dentry to associate + * + * Associate @sd with @dentry. This is protected by sysfs_lock + * to avoid race with sysfs_d_iput(). + * + * LOCKING: + * spin_lock(sysfs_lock) + */ static void sysfs_attach_dentry(struct sysfs_dirent *sd, struct dentry *dentry) { dentry->d_op = &sysfs_dentry_ops; dentry->d_fsdata = sysfs_get(sd); - - /* protect sd->s_dentry against sysfs_d_iput */ - spin_lock(&sysfs_lock); - sd->s_dentry = dentry; - spin_unlock(&sysfs_lock); - + sd->s_dentry = dentry; /* protected with sysfs_lock */ d_rehash(dentry); } +/** + * sysfs_attach_dirent - attach sysfs_dirent to its parent and dentry + * @sd: sysfs_dirent to attach + * @parent_sd: parent to attach to (optional) + * @dentry: dentry to be associated to @sd (optional) + * + * Attach @sd to @parent_sd and/or @dentry. Both are optional. + * + * LOCKING: + * spin_lock(sysfs_lock) + */ void sysfs_attach_dirent(struct sysfs_dirent *sd, struct sysfs_dirent *parent_sd, struct dentry *dentry) { @@ -325,7 +344,7 @@ void sysfs_attach_dirent(struct sysfs_di * Look for sysfs_dirent with name @name under @parent_sd. * * LOCKING: - * mutex_lock(parent->i_mutex) + * spin_lock(sysfs_lock) * * RETURNS: * Pointer to sysfs_dirent if found, NULL if not. @@ -350,7 +369,7 @@ struct sysfs_dirent *sysfs_find_dirent(s * it if found. * * LOCKING: - * Kernel thread context (may sleep) + * None. Grabs sysfs_lock. * * RETURNS: * Pointer to sysfs_dirent if found, NULL if not. @@ -360,10 +379,10 @@ struct sysfs_dirent *sysfs_get_dirent(st { struct sysfs_dirent *sd; - mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex); + spin_lock(&sysfs_lock); sd = sysfs_find_dirent(parent_sd, name); sysfs_get(sd); - mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex); + spin_unlock(&sysfs_lock); return sd; } @@ -409,14 +428,20 @@ static int create_dir(struct kobject *ko } /* link in */ + spin_lock(&sysfs_lock); + error = -EEXIST; - if (sysfs_find_dirent(parent_sd, name)) + if (sysfs_find_dirent(parent_sd, name)) { + spin_unlock(&sysfs_lock); goto out_iput; + } sysfs_instantiate(dentry, inode); inc_nlink(parent->d_inode); sysfs_attach_dirent(sd, parent_sd, dentry); + spin_unlock(&sysfs_lock); + *p_sd = sd; error = 0; goto out_unlock; /* pin directory dentry in core */ @@ -494,6 +519,8 @@ static struct dentry * sysfs_lookup(stru if (!inode) return ERR_PTR(-ENOMEM); + spin_lock(&sysfs_lock); + if (inode->i_state & I_NEW) { /* initialize inode according to type */ switch (sysfs_type(sd)) { @@ -517,6 +544,8 @@ static struct dentry * sysfs_lookup(stru sysfs_instantiate(dentry, inode); sysfs_attach_dentry(sd, dentry); + spin_unlock(&sysfs_lock); + return NULL; } @@ -527,17 +556,13 @@ const struct inode_operations sysfs_dir_ static void remove_dir(struct sysfs_dirent *sd) { - struct dentry *parent = sd->s_parent->s_dentry; - - mutex_lock(&parent->d_inode->i_mutex); - + spin_lock(&sysfs_lock); sysfs_unlink_sibling(sd); sd->s_flags |= SYSFS_FLAG_REMOVED; + spin_unlock(&sysfs_lock); pr_debug(" o %s removing done\n", sd->s_name); - mutex_unlock(&parent->d_inode->i_mutex); - sysfs_drop_dentry(sd); sysfs_deactivate(sd); sysfs_put(sd); @@ -553,15 +578,12 @@ static void __sysfs_remove_dir(struct sy { struct sysfs_dirent *removed = NULL; struct sysfs_dirent **pos; - struct dentry *dir; if (!dir_sd) return; - dir = dir_sd->s_dentry; - pr_debug("sysfs %s: removing dir\n", dir_sd->s_name); - mutex_lock(&dir->d_inode->i_mutex); + spin_lock(&sysfs_lock); pos = &dir_sd->s_children; while (*pos) { struct sysfs_dirent *sd = *pos; @@ -574,7 +596,7 @@ static void __sysfs_remove_dir(struct sy } else pos = &(*pos)->s_sibling; } - mutex_unlock(&dir->d_inode->i_mutex); + spin_unlock(&sysfs_lock); while (removed) { struct sysfs_dirent *sd = removed; @@ -622,7 +644,6 @@ int sysfs_rename_dir(struct kobject *kob if (!new_parent_sd) return -EFAULT; - down_write(&sysfs_rename_sem); mutex_lock(&new_parent->d_inode->i_mutex); new_dentry = lookup_one_len(new_name, new_parent, strlen(new_name)); @@ -662,12 +683,16 @@ int sysfs_rename_dir(struct kobject *kob d_add(new_dentry, NULL); d_move(sd->s_dentry, new_dentry); + spin_lock(&sysfs_lock); + sysfs_unlink_sibling(sd); sysfs_get(new_parent_sd); sysfs_put(sd->s_parent); sd->s_parent = new_parent_sd; sysfs_link_sibling(sd); + spin_unlock(&sysfs_lock); + error = 0; goto out_unlock; @@ -679,7 +704,6 @@ int sysfs_rename_dir(struct kobject *kob dput(new_dentry); out_unlock: mutex_unlock(&new_parent->d_inode->i_mutex); - up_write(&sysfs_rename_sem); return error; } @@ -718,12 +742,15 @@ again: dput(new_dentry); /* Remove from old parent's list and insert into new parent's list. */ + spin_lock(&sysfs_lock); + sysfs_unlink_sibling(sd); sysfs_get(new_parent_sd); sysfs_put(sd->s_parent); sd->s_parent = new_parent_sd; sysfs_link_sibling(sd); + spin_unlock(&sysfs_lock); out: mutex_unlock(&new_parent_dentry->d_inode->i_mutex); mutex_unlock(&old_parent_dentry->d_inode->i_mutex); @@ -737,11 +764,12 @@ static int sysfs_dir_open(struct inode * struct sysfs_dirent * parent_sd = dentry->d_fsdata; struct sysfs_dirent * sd; - mutex_lock(&dentry->d_inode->i_mutex); sd = sysfs_new_dirent("_DIR_", 0, 0); - if (sd) + if (sd) { + spin_lock(&sysfs_lock); sysfs_attach_dirent(sd, parent_sd, NULL); - mutex_unlock(&dentry->d_inode->i_mutex); + spin_unlock(&sysfs_lock); + } file->private_data = sd; return sd ? 0 : -ENOMEM; @@ -749,12 +777,11 @@ static int sysfs_dir_open(struct inode * static int sysfs_dir_close(struct inode *inode, struct file *file) { - struct dentry * dentry = file->f_path.dentry; struct sysfs_dirent * cursor = file->private_data; - mutex_lock(&dentry->d_inode->i_mutex); + spin_lock(&sysfs_lock); sysfs_unlink_sibling(cursor); - mutex_unlock(&dentry->d_inode->i_mutex); + spin_unlock(&sysfs_lock); release_sysfs_dirent(cursor); @@ -795,6 +822,8 @@ static int sysfs_readdir(struct file * f i++; /* fallthrough */ default: + spin_lock(&sysfs_lock); + pos = &parent_sd->s_children; while (*pos != cursor) pos = &(*pos)->s_sibling; @@ -827,6 +856,8 @@ static int sysfs_readdir(struct file * f /* put cursor back in */ cursor->s_sibling = *pos; *pos = cursor; + + spin_unlock(&sysfs_lock); } return 0; } @@ -835,7 +866,6 @@ static loff_t sysfs_dir_lseek(struct fil { struct dentry * dentry = file->f_path.dentry; - mutex_lock(&dentry->d_inode->i_mutex); switch (origin) { case 1: offset += file->f_pos; @@ -843,10 +873,11 @@ static loff_t sysfs_dir_lseek(struct fil if (offset >= 0) break; default: - mutex_unlock(&file->f_path.dentry->d_inode->i_mutex); return -EINVAL; } if (offset != file->f_pos) { + spin_lock(&sysfs_lock); + file->f_pos = offset; if (file->f_pos >= 2) { struct sysfs_dirent *sd = dentry->d_fsdata; @@ -867,8 +898,10 @@ static loff_t sysfs_dir_lseek(struct fil cursor->s_sibling = *pos; *pos = cursor; } + + spin_unlock(&sysfs_lock); } - mutex_unlock(&dentry->d_inode->i_mutex); + return offset; } @@ -934,7 +967,9 @@ struct sysfs_dirent *sysfs_create_shadow sd->s_elem.dir.kobj = kobj; /* point to parent_sd but don't attach to it */ sd->s_parent = sysfs_get(parent_sd); + spin_lock(&sysfs_lock); sysfs_attach_dirent(sd, NULL, shadow); + spin_unlock(&sysfs_lock); d_instantiate(shadow, igrab(inode)); inc_nlink(inode); diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index acc9890..f2e3c88 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -415,29 +415,28 @@ const struct file_operations sysfs_file_ int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr, int type) { - struct dentry *dir = dir_sd->s_dentry; umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG; struct sysfs_dirent *sd; - int error = 0; - mutex_lock(&dir->d_inode->i_mutex); + sd = sysfs_new_dirent(attr->name, mode, type); + if (!sd) + return -ENOMEM; + sd->s_elem.attr.attr = (void *)attr; - if (sysfs_find_dirent(dir_sd, attr->name)) { - error = -EEXIST; - goto out_unlock; - } + spin_lock(&sysfs_lock); - sd = sysfs_new_dirent(attr->name, mode, type); - if (!sd) { - error = -ENOMEM; - goto out_unlock; + if (!sysfs_find_dirent(dir_sd, attr->name)) { + sysfs_attach_dirent(sd, dir_sd, NULL); + sd = NULL; } - sd->s_elem.attr.attr = (void *)attr; - sysfs_attach_dirent(sd, dir_sd, NULL); - out_unlock: - mutex_unlock(&dir->d_inode->i_mutex); - return error; + spin_unlock(&sysfs_lock); + + if (sd) { + sysfs_put(sd); + return -EEXIST; + } + return 0; } diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index 4077ab5..705c03d 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -283,15 +283,11 @@ void sysfs_drop_dentry(struct sysfs_dire int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name) { - struct dentry *dir = dir_sd->s_dentry; struct sysfs_dirent **pos, *sd; int found = 0; - if (dir->d_inode == NULL) - /* no inode means this hasn't been made visible yet */ - return -ENOENT; + spin_lock(&sysfs_lock); - mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); for (pos = &dir_sd->s_children; *pos; pos = &(*pos)->s_sibling) { sd = *pos; @@ -305,7 +301,8 @@ int sysfs_hash_and_remove(struct sysfs_d break; } } - mutex_unlock(&dir->d_inode->i_mutex); + + spin_unlock(&sysfs_lock); if (!found) return -ENOENT; diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index 43cc522..b05f6a6 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -44,20 +44,6 @@ static void fill_object_path(struct sysf } } -static int sysfs_add_link(struct sysfs_dirent * parent_sd, const char * name, - struct sysfs_dirent * target_sd) -{ - struct sysfs_dirent * sd; - - sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); - if (!sd) - return -ENOMEM; - - sd->s_elem.symlink.target_sd = target_sd; - sysfs_attach_dirent(sd, parent_sd, NULL); - return 0; -} - /** * sysfs_create_link - create symlink between two objects. * @kobj: object whose directory we're creating the link in. @@ -68,7 +54,8 @@ int sysfs_create_link(struct kobject * k { struct sysfs_dirent *parent_sd = NULL; struct sysfs_dirent *target_sd = NULL; - int error = -EEXIST; + struct sysfs_dirent *sd = NULL; + int error; BUG_ON(!name); @@ -78,8 +65,9 @@ int sysfs_create_link(struct kobject * k } else parent_sd = kobj->sd; + error = -EFAULT; if (!parent_sd) - return -EFAULT; + goto out_put; /* target->sd can go away beneath us but is protected with * kobj_sysfs_assoc_lock. Fetch target_sd from it. @@ -89,17 +77,30 @@ int sysfs_create_link(struct kobject * k target_sd = sysfs_get(target->sd); spin_unlock(&kobj_sysfs_assoc_lock); + error = -ENOENT; if (!target_sd) - return -ENOENT; + goto out_put; + + error = -ENOMEM; + sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); + if (!sd) + goto out_put; + sd->s_elem.symlink.target_sd = target_sd; - mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex); - if (!sysfs_find_dirent(parent_sd, name)) - error = sysfs_add_link(parent_sd, name, target_sd); - mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex); + spin_lock(&sysfs_lock); + error = -EEXIST; + if (sysfs_find_dirent(parent_sd, name)) + goto out_unlock; + sysfs_attach_dirent(sd, parent_sd, NULL); + spin_unlock(&sysfs_lock); - if (error) - sysfs_put(target_sd); + return 0; + out_unlock: + spin_unlock(&sysfs_lock); + out_put: + sysfs_put(target_sd); + sysfs_put(sd); return error; } @@ -144,9 +145,9 @@ static int sysfs_getlink(struct dentry * struct sysfs_dirent *target_sd = sd->s_elem.symlink.target_sd; int error; - down_read(&sysfs_rename_sem); + spin_lock(&sysfs_lock); error = sysfs_get_target_path(parent_sd, target_sd, path); - up_read(&sysfs_rename_sem); + spin_unlock(&sysfs_lock); return error; } diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 27a5f4b..476d58b 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -83,7 +83,6 @@ extern int sysfs_setattr(struct dentry * extern spinlock_t sysfs_lock; extern spinlock_t kobj_sysfs_assoc_lock; -extern struct rw_semaphore sysfs_rename_sem; extern struct super_block * sysfs_sb; extern const struct file_operations sysfs_dir_operations; extern const struct file_operations sysfs_file_operations; -- 1.4.3.4 - 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/