Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756565AbYLLVyz (ORCPT ); Fri, 12 Dec 2008 16:54:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755570AbYLLVwT (ORCPT ); Fri, 12 Dec 2008 16:52:19 -0500 Received: from mx2.redhat.com ([66.187.237.31]:56002 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754620AbYLLVwQ (ORCPT ); Fri, 12 Dec 2008 16:52:16 -0500 From: Eric Paris Subject: [RFC PATCH -v4 09/14] dnotify: reimplement dnotify using fsnotify To: linux-kernel@vger.kernel.org Cc: a.p.zijlstra@chello.nl, viro@ZenIV.linux.org.uk, hch@infradead.org, zbr@ioremap.net, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk Date: Fri, 12 Dec 2008 16:52:02 -0500 Message-ID: <20081212215201.27112.65352.stgit@paris.rdu.redhat.com> In-Reply-To: <20081212213915.27112.57526.stgit@paris.rdu.redhat.com> References: <20081212213915.27112.57526.stgit@paris.rdu.redhat.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 19864 Lines: 675 Reimplement dnotify using fsnotify. Signed-off-by: Eric Paris --- fs/fcntl.c | 4 + fs/notify/dnotify/Kconfig | 1 fs/notify/dnotify/dnotify.c | 322 ++++++++++++++++++++++++++++++++----------- include/linux/dnotify.h | 29 +--- include/linux/fs.h | 5 - include/linux/fsnotify.h | 71 +++------ 6 files changed, 271 insertions(+), 161 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index 549daf8..dcc733e 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -327,6 +327,10 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, break; case F_NOTIFY: err = fcntl_dirnotify(fd, filp, arg); + if (err) + break; + if (filp->f_op && filp->f_op->dir_notify) + err = filp->f_op->dir_notify(filp, arg); break; default: break; diff --git a/fs/notify/dnotify/Kconfig b/fs/notify/dnotify/Kconfig index 26adf5d..904ff8d 100644 --- a/fs/notify/dnotify/Kconfig +++ b/fs/notify/dnotify/Kconfig @@ -1,5 +1,6 @@ config DNOTIFY bool "Dnotify support" + depends on FSNOTIFY default y help Dnotify is a directory-based per-fd file change notification system diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 676073b..dae1bd6 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -21,24 +21,147 @@ #include #include #include +#include + +#include "../fsnotify.h" int dir_notify_enable __read_mostly = 1; static struct kmem_cache *dn_cache __read_mostly; -static void redo_inode_mask(struct inode *inode) +static int inode_dir_notify(struct fsnotify_group *group, struct fsnotify_event *event); +static void clear_mark_dir_notify(struct fsnotify_mark_entry *entry, struct inode *inode, unsigned int flags); +static int should_send_event_dir_notify(struct fsnotify_group *group, struct inode *inode, __u64 mask); + +static struct fsnotify_ops dnotify_fsnotify_ops = { + .event_to_notif = inode_dir_notify, + .mark_clear_inode = clear_mark_dir_notify, + .should_send_event = should_send_event_dir_notify, + .free_group_priv = NULL, + .free_event_priv = NULL, + .free_mark_priv = NULL, +}; + +/* this horribleness only works because dnotify only ever has 1 group */ +static inline struct fsnotify_mark_entry *dnotify_get_mark(struct inode *inode) +{ + struct fsnotify_mark_entry *lentry; + struct fsnotify_mark_entry *entry = NULL; + + spin_lock(&inode->i_lock); + list_for_each_entry(lentry, &inode->i_fsnotify_mark_entries, i_list) { + if (lentry->group->ops == &dnotify_fsnotify_ops) { + fsnotify_get_mark(lentry); + entry = lentry; + break; + } + } + spin_unlock(&inode->i_lock); + return entry; +} + +/* holding the entry->lock to protect private data. */ +static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry) { unsigned long new_mask; struct dnotify_struct *dn; new_mask = 0; - for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next) - new_mask |= dn->dn_mask & ~DN_MULTISHOT; - inode->i_dnotify_mask = new_mask; + dn = (struct dnotify_struct *)entry->private; + for (; dn != NULL; dn = dn->dn_next) + new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT); + entry->mask = new_mask; + + if (entry->inode) + fsnotify_recalc_inode_mask(entry->inode); +} + +static int inode_dir_notify(struct fsnotify_group *group, struct fsnotify_event *event) +{ + struct fsnotify_mark_entry *entry = NULL; + struct inode *to_tell; + struct dnotify_struct *dn; + struct dnotify_struct **prev; + struct fown_struct *fown; + int changed = 0; + + to_tell = event->to_tell; + + spin_lock(&to_tell->i_lock); + entry = fsnotify_find_mark_entry(group, to_tell); + spin_unlock(&to_tell->i_lock); + + /* unlikely since we alreay passed should_send_event_dir_notify() */ + if (unlikely(!entry)) + return 0; + + spin_lock(&entry->lock); + prev = (struct dnotify_struct **)&entry->private; + while ((dn = *prev) != NULL) { + if ((dn->dn_mask & event->mask) == 0) { + prev = &dn->dn_next; + continue; + } + fown = &dn->dn_filp->f_owner; + send_sigio(fown, dn->dn_fd, POLL_MSG); + if (dn->dn_mask & FS_DN_MULTISHOT) + prev = &dn->dn_next; + else { + *prev = dn->dn_next; + changed = 1; + kmem_cache_free(dn_cache, dn); + } + } + if (changed) + dnotify_recalc_inode_mask(entry); + + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); + + return 0; +} + +static void clear_mark_dir_notify(struct fsnotify_mark_entry *entry, struct inode *inode, unsigned int flags) +{ + /* if we got here when this inode just closed it's last dentry or when + * the inode is being kicked out of core we screwed up since it should + * have already been flushed in dnotify_flush() */ + BUG(); +} + +static int should_send_event_dir_notify(struct fsnotify_group *group, struct inode *inode, __u64 mask) +{ + struct fsnotify_mark_entry *entry; + int send; + + /* !dir_notify_enable should never get here, don't waste time checking + if (!dir_notify_enable) + return 0; */ + + /* not a dir, dnotify doesn't care */ + if (!S_ISDIR(inode->i_mode)) + return 0; + + spin_lock(&inode->i_lock); + entry = fsnotify_find_mark_entry(group, inode); + spin_unlock(&inode->i_lock); + + /* no mark means no dnotify watch */ + if (!entry) + return 0; + + spin_lock(&entry->lock); + send = !!(mask & entry->mask); + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); + + return send; } void dnotify_flush(struct file *filp, fl_owner_t id) { + struct fsnotify_group *dnotify_group = NULL; + struct fsnotify_mark_entry *entry; struct dnotify_struct *dn; struct dnotify_struct **prev; struct inode *inode; @@ -46,22 +169,66 @@ void dnotify_flush(struct file *filp, fl_owner_t id) inode = filp->f_path.dentry->d_inode; if (!S_ISDIR(inode->i_mode)) return; - spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; + + entry = dnotify_get_mark(inode); + if (!entry) + return; + + spin_lock(&entry->lock); + prev = (struct dnotify_struct **)&entry->private; while ((dn = *prev) != NULL) { if ((dn->dn_owner == id) && (dn->dn_filp == filp)) { *prev = dn->dn_next; - redo_inode_mask(inode); + dnotify_recalc_inode_mask(entry); kmem_cache_free(dn_cache, dn); break; } prev = &dn->dn_next; } - spin_unlock(&inode->i_lock); + + /* last dnotify watch on this inode is gone */ + if (entry->private == NULL) + dnotify_group = entry->group; + + spin_unlock(&entry->lock); + + if (dnotify_group) { + fsnotify_destroy_mark_by_entry(entry); + fsnotify_put_group(dnotify_group); + } + + fsnotify_put_mark(entry); +} + +/* this conversion is done only at watch creation */ +static inline unsigned long convert_arg(unsigned long arg) +{ + unsigned long new_mask = 0; + + if (arg & DN_MULTISHOT) + new_mask |= FS_DN_MULTISHOT; + if (arg & DN_DELETE) + new_mask |= (FS_DELETE | FS_MOVED_FROM); + if (arg & DN_MODIFY) + new_mask |= FS_MODIFY; + if (arg & DN_ACCESS) + new_mask |= FS_ACCESS; + if (arg & DN_ATTRIB) + new_mask |= FS_ATTRIB; + if (arg & DN_RENAME) + new_mask |= FS_DN_RENAME; + if (arg & DN_CREATE) + new_mask |= (FS_CREATE | FS_MOVED_TO); + + new_mask |= (new_mask & FS_EVENTS_WITH_CHILD) << 32; + + return new_mask; } int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) { + struct fsnotify_group *dnotify_group; + struct fsnotify_mark_entry *entry; struct dnotify_struct *dn; struct dnotify_struct *odn; struct dnotify_struct **prev; @@ -69,27 +236,64 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) fl_owner_t id = current->files; struct file *f; int error = 0; + __u64 mask; + + if (!dir_notify_enable) + return -EINVAL; if ((arg & ~DN_MULTISHOT) == 0) { dnotify_flush(filp, id); return 0; } - if (!dir_notify_enable) - return -EINVAL; inode = filp->f_path.dentry->d_inode; if (!S_ISDIR(inode->i_mode)) return -ENOTDIR; + + /* expect most fcntl to add new rather than augment old */ dn = kmem_cache_alloc(dn_cache, GFP_KERNEL); if (dn == NULL) return -ENOMEM; - spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; + + /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */ + mask = convert_arg(arg); + + /* + * I really don't like using ALL_DNOTIFY_EVENTS. We could probably do + * better setting the group->mask equal to only those dnotify watches care + * about, but removing events means running the entire group->mark_entries + * list to recalculate the mask. Also makes it harder to find the right + * group, but this is not a fast path, so harder doesn't mean bad. + * Maybe a future performance win since it could result in faster fsnotify() + * processing. + */ + dnotify_group = fsnotify_obtain_group(UINT_MAX, UINT_MAX, ALL_DNOTIFY_EVENTS, &dnotify_fsnotify_ops); + /* screw it, i don't care */ + if (IS_ERR(dnotify_group)) { + error = PTR_ERR(dnotify_group); + goto out_free; + } + + entry = fsnotify_mark_add(dnotify_group, inode, mask); + if (!entry) { + error = -ENOMEM; + goto out_put_group; + } + + spin_lock(&entry->lock); + /* entry->private == NULL means that this is a new inode mark. + * take a group reference for it. */ + if (entry->private == NULL) + fsnotify_get_group(dnotify_group); + + prev = (struct dnotify_struct **)&entry->private; while ((odn = *prev) != NULL) { + /* do we already have a dnotify struct and we are just adding more events? */ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) { odn->dn_fd = fd; - odn->dn_mask |= arg; - inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; - goto out_free; + odn->dn_mask |= mask; + /* recalculate the entry->mask and entry->inode->i_fsnotify_mask */ + dnotify_recalc_inode_mask(entry); + goto out_unlock; } prev = &odn->dn_next; } @@ -98,92 +302,38 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) f = fcheck(fd); rcu_read_unlock(); /* we'd lost the race with close(), sod off silently */ - /* note that inode->i_lock prevents reordering problems - * between accesses to descriptor table and ->i_dnotify */ + /* note that entry->lock prevents reordering problems + * between accesses to descriptor table and the private data in the + * inode mark, aka the dnotify_flush when the fd was closed */ if (f != filp) - goto out_free; + goto out_unlock; error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); if (error) - goto out_free; + goto out_unlock; - dn->dn_mask = arg; + dn->dn_mask = mask; dn->dn_fd = fd; dn->dn_filp = filp; dn->dn_owner = id; - inode->i_dnotify_mask |= arg & ~DN_MULTISHOT; - dn->dn_next = inode->i_dnotify; - inode->i_dnotify = dn; - spin_unlock(&inode->i_lock); - - if (filp->f_op && filp->f_op->dir_notify) - return filp->f_op->dir_notify(filp, arg); + dn->dn_next = entry->private; + entry->private = dn; + dnotify_recalc_inode_mask(entry); + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); + fsnotify_put_group(dnotify_group); return 0; +out_unlock: + spin_unlock(&entry->lock); + fsnotify_put_mark(entry); +out_put_group: + fsnotify_put_group(dnotify_group); out_free: - spin_unlock(&inode->i_lock); kmem_cache_free(dn_cache, dn); return error; } -void __inode_dir_notify(struct inode *inode, unsigned long event) -{ - struct dnotify_struct * dn; - struct dnotify_struct **prev; - struct fown_struct * fown; - int changed = 0; - - spin_lock(&inode->i_lock); - prev = &inode->i_dnotify; - while ((dn = *prev) != NULL) { - if ((dn->dn_mask & event) == 0) { - prev = &dn->dn_next; - continue; - } - fown = &dn->dn_filp->f_owner; - send_sigio(fown, dn->dn_fd, POLL_MSG); - if (dn->dn_mask & DN_MULTISHOT) - prev = &dn->dn_next; - else { - *prev = dn->dn_next; - changed = 1; - kmem_cache_free(dn_cache, dn); - } - } - if (changed) - redo_inode_mask(inode); - spin_unlock(&inode->i_lock); -} - -EXPORT_SYMBOL(__inode_dir_notify); - -/* - * This is hopelessly wrong, but unfixable without API changes. At - * least it doesn't oops the kernel... - * - * To safely access ->d_parent we need to keep d_move away from it. Use the - * dentry's d_lock for this. - */ -void dnotify_parent(struct dentry *dentry, unsigned long event) -{ - struct dentry *parent; - - if (!dir_notify_enable) - return; - - spin_lock(&dentry->d_lock); - parent = dentry->d_parent; - if (parent->d_inode->i_dnotify_mask & event) { - dget(parent); - spin_unlock(&dentry->d_lock); - __inode_dir_notify(parent->d_inode, event); - dput(parent); - } else { - spin_unlock(&dentry->d_lock); - } -} -EXPORT_SYMBOL_GPL(dnotify_parent); - static int __init dnotify_init(void) { dn_cache = kmem_cache_create("dnotify_cache", diff --git a/include/linux/dnotify.h b/include/linux/dnotify.h index 102a902..e8c4256 100644 --- a/include/linux/dnotify.h +++ b/include/linux/dnotify.h @@ -10,7 +10,7 @@ struct dnotify_struct { struct dnotify_struct * dn_next; - unsigned long dn_mask; + __u64 dn_mask; int dn_fd; struct file * dn_filp; fl_owner_t dn_owner; @@ -21,23 +21,18 @@ struct dnotify_struct { #ifdef CONFIG_DNOTIFY -extern void __inode_dir_notify(struct inode *, unsigned long); +#define ALL_DNOTIFY_EVENTS (FS_DELETE | FS_DELETE_CHILD |\ + FS_MODIFY | FS_MODIFY_CHILD |\ + FS_ACCESS | FS_ACCESS_CHILD |\ + FS_ATTRIB | FS_ATTRIB_CHILD |\ + FS_CREATE | FS_DN_RENAME |\ + FS_MOVED_FROM | FS_MOVED_TO) + extern void dnotify_flush(struct file *, fl_owner_t); extern int fcntl_dirnotify(int, struct file *, unsigned long); -extern void dnotify_parent(struct dentry *, unsigned long); - -static inline void inode_dir_notify(struct inode *inode, unsigned long event) -{ - if (inode->i_dnotify_mask & (event)) - __inode_dir_notify(inode, event); -} #else -static inline void __inode_dir_notify(struct inode *inode, unsigned long event) -{ -} - static inline void dnotify_flush(struct file *filp, fl_owner_t id) { } @@ -47,14 +42,6 @@ static inline int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) return -EINVAL; } -static inline void dnotify_parent(struct dentry *dentry, unsigned long event) -{ -} - -static inline void inode_dir_notify(struct inode *inode, unsigned long event) -{ -} - #endif /* CONFIG_DNOTIFY */ #endif /* __KERNEL __ */ diff --git a/include/linux/fs.h b/include/linux/fs.h index b5a7bce..f945763 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -670,11 +670,6 @@ struct inode { struct list_head i_fsnotify_mark_entries; /* fsnotify mark entries */ #endif -#ifdef CONFIG_DNOTIFY - unsigned long i_dnotify_mask; /* Directory notify events */ - struct dnotify_struct *i_dnotify; /* for directory notifications */ -#endif - #ifdef CONFIG_INOTIFY struct list_head inotify_watches; /* watches on this inode */ struct mutex inotify_mutex; /* protects the watches list */ diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 971ada9..791d288 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -135,13 +135,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir, __u64 new_dir_mask = 0; if (old_dir == new_dir) { - inode_dir_notify(old_dir, DN_RENAME); old_dir_mask = FS_DN_RENAME; - } else { - inode_dir_notify(old_dir, DN_DELETE); - old_dir_mask = FS_DELETE; - inode_dir_notify(new_dir, DN_CREATE); - new_dir_mask = FS_CREATE; } if (isdir) { @@ -181,7 +175,6 @@ static inline void fsnotify_nameremove(struct dentry *dentry, int isdir) { if (isdir) isdir = IN_ISDIR; - dnotify_parent(dentry, DN_DELETE); inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name); fsnotify_parent(dentry, FS_DELETE|isdir); @@ -222,7 +215,6 @@ static inline void fsnotify_link_count(struct inode *inode) */ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry) { - inode_dir_notify(inode, DN_CREATE); inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name, dentry->d_inode); audit_inode_child(dentry->d_name.name, dentry, inode); @@ -237,7 +229,6 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry) */ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry) { - inode_dir_notify(dir, DN_CREATE); inotify_inode_queue_event(dir, IN_CREATE, 0, new_dentry->d_name.name, inode); fsnotify_link_count(inode); @@ -251,7 +242,6 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct */ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry) { - inode_dir_notify(inode, DN_CREATE); inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0, dentry->d_name.name, dentry->d_inode); audit_inode_child(dentry->d_name.name, dentry, inode); @@ -271,7 +261,6 @@ static inline void fsnotify_access(struct file *file) if (S_ISDIR(inode->i_mode)) mask |= IN_ISDIR; - dnotify_parent(dentry, DN_ACCESS); inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); @@ -291,7 +280,6 @@ static inline void fsnotify_modify(struct file *file) if (S_ISDIR(inode->i_mode)) mask |= IN_ISDIR; - dnotify_parent(dentry, DN_MODIFY); inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); @@ -307,7 +295,6 @@ static inline void fsnotify_open_exec(struct file *file) struct dentry *dentry = file->f_path.dentry; struct inode *inode = dentry->d_inode; - dnotify_parent(dentry, DN_ACCESS); inotify_dentry_parent_queue_event(dentry, IN_ACCESS, 0, dentry->d_name.name); inotify_inode_queue_event(inode, IN_ACCESS, 0, NULL, NULL); @@ -380,49 +367,35 @@ static inline void fsnotify_xattr(struct dentry *dentry) static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) { struct inode *inode = dentry->d_inode; - int dn_mask = 0; - u32 in_mask = 0; + __u64 mask = 0; + + if (ia_valid & ATTR_UID) + mask |= IN_ATTRIB; + if (ia_valid & ATTR_GID) + mask |= IN_ATTRIB; + if (ia_valid & ATTR_SIZE) + mask |= IN_MODIFY; - if (ia_valid & ATTR_UID) { - in_mask |= IN_ATTRIB; - dn_mask |= DN_ATTRIB; - } - if (ia_valid & ATTR_GID) { - in_mask |= IN_ATTRIB; - dn_mask |= DN_ATTRIB; - } - if (ia_valid & ATTR_SIZE) { - in_mask |= IN_MODIFY; - dn_mask |= DN_MODIFY; - } /* both times implies a utime(s) call */ if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) - { - in_mask |= IN_ATTRIB; - dn_mask |= DN_ATTRIB; - } else if (ia_valid & ATTR_ATIME) { - in_mask |= IN_ACCESS; - dn_mask |= DN_ACCESS; - } else if (ia_valid & ATTR_MTIME) { - in_mask |= IN_MODIFY; - dn_mask |= DN_MODIFY; - } - if (ia_valid & ATTR_MODE) { - in_mask |= IN_ATTRIB; - dn_mask |= DN_ATTRIB; - } + mask |= IN_ATTRIB; + else if (ia_valid & ATTR_ATIME) + mask |= IN_ACCESS; + else if (ia_valid & ATTR_MTIME) + mask |= IN_MODIFY; + + if (ia_valid & ATTR_MODE) + mask |= IN_ATTRIB; - if (dn_mask) - dnotify_parent(dentry, dn_mask); - if (in_mask) { + if (mask) { if (S_ISDIR(inode->i_mode)) - in_mask |= IN_ISDIR; - inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL); - inotify_dentry_parent_queue_event(dentry, in_mask, 0, + mask |= IN_ISDIR; + inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); - fsnotify_parent(dentry, in_mask); - fsnotify(inode, in_mask, inode, FSNOTIFY_EVENT_INODE); + fsnotify_parent(dentry, mask); + fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } } -- 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/