From e09b41010ba33a20a87472ee821fa407a5b8da36 Mon Sep 17 00:00:00 2001 From: José Pekkarinen Date: Mon, 11 Apr 2016 10:41:07 +0300 Subject: These changes are the raw update to linux-4.4.6-rt14. Kernel sources are taken from kernel.org, and rt patch from the rt wiki download page. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen --- kernel/fs/notify/mark.c | 113 ++++++++++++++++++++++++++++-------------------- 1 file changed, 65 insertions(+), 48 deletions(-) (limited to 'kernel/fs/notify/mark.c') diff --git a/kernel/fs/notify/mark.c b/kernel/fs/notify/mark.c index 39ddcaf09..fc0df4442 100644 --- a/kernel/fs/notify/mark.c +++ b/kernel/fs/notify/mark.c @@ -122,26 +122,27 @@ u32 fsnotify_recalc_mask(struct hlist_head *head) } /* - * Any time a mark is getting freed we end up here. - * The caller had better be holding a reference to this mark so we don't actually - * do the final put under the mark->lock + * Remove mark from inode / vfsmount list, group list, drop inode reference + * if we got one. + * + * Must be called with group->mark_mutex held. */ -void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, - struct fsnotify_group *group) +void fsnotify_detach_mark(struct fsnotify_mark *mark) { struct inode *inode = NULL; + struct fsnotify_group *group = mark->group; BUG_ON(!mutex_is_locked(&group->mark_mutex)); spin_lock(&mark->lock); /* something else already called this function on this mark */ - if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { spin_unlock(&mark->lock); return; } - mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED; if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { inode = mark->inode; @@ -150,6 +151,12 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, fsnotify_destroy_vfsmount_mark(mark); else BUG(); + /* + * Note that we didn't update flags telling whether inode cares about + * what's happening with children. We update these flags from + * __fsnotify_parent() lazily when next event happens on one of our + * children. + */ list_del_init(&mark->g_list); @@ -157,18 +164,32 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) iput(inode); - /* release lock temporarily */ - mutex_unlock(&group->mark_mutex); + + atomic_dec(&group->num_marks); +} + +/* + * Free fsnotify mark. The freeing is actually happening from a kthread which + * first waits for srcu period end. Caller must have a reference to the mark + * or be protected by fsnotify_mark_srcu. + */ +void fsnotify_free_mark(struct fsnotify_mark *mark) +{ + struct fsnotify_group *group = mark->group; + + spin_lock(&mark->lock); + /* something else already called this function on this mark */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + spin_unlock(&mark->lock); + return; + } + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + spin_unlock(&mark->lock); spin_lock(&destroy_lock); list_add(&mark->g_list, &destroy_list); spin_unlock(&destroy_lock); wake_up(&destroy_waitq); - /* - * We don't necessarily have a ref on mark from caller so the above destroy - * may have actually freed it, unless this group provides a 'freeing_mark' - * function which must be holding a reference. - */ /* * Some groups like to know that marks are being freed. This is a @@ -177,50 +198,45 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, */ if (group->ops->freeing_mark) group->ops->freeing_mark(mark, group); - - /* - * __fsnotify_update_child_dentry_flags(inode); - * - * I really want to call that, but we can't, we have no idea if the inode - * still exists the second we drop the mark->lock. - * - * The next time an event arrive to this inode from one of it's children - * __fsnotify_parent will see that the inode doesn't care about it's - * children and will update all of these flags then. So really this - * is just a lazy update (and could be a perf win...) - */ - - atomic_dec(&group->num_marks); - - mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); } void fsnotify_destroy_mark(struct fsnotify_mark *mark, struct fsnotify_group *group) { mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); - fsnotify_destroy_mark_locked(mark, group); + fsnotify_detach_mark(mark); mutex_unlock(&group->mark_mutex); + fsnotify_free_mark(mark); } -/* - * Destroy all marks in the given list. The marks must be already detached from - * the original inode / vfsmount. - */ -void fsnotify_destroy_marks(struct list_head *to_free) +void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock) { - struct fsnotify_mark *mark, *lmark; - struct fsnotify_group *group; - - list_for_each_entry_safe(mark, lmark, to_free, free_list) { - spin_lock(&mark->lock); - fsnotify_get_group(mark->group); - group = mark->group; - spin_unlock(&mark->lock); + struct fsnotify_mark *mark; - fsnotify_destroy_mark(mark, group); + while (1) { + /* + * We have to be careful since we can race with e.g. + * fsnotify_clear_marks_by_group() and once we drop 'lock', + * mark can get removed from the obj_list and destroyed. But + * we are holding mark reference so mark cannot be freed and + * calling fsnotify_destroy_mark() more than once is fine. + */ + spin_lock(lock); + if (hlist_empty(head)) { + spin_unlock(lock); + break; + } + mark = hlist_entry(head->first, struct fsnotify_mark, obj_list); + /* + * We don't update i_fsnotify_mask / mnt_fsnotify_mask here + * since inode / mount is going away anyway. So just remove + * mark from the list. + */ + hlist_del_init_rcu(&mark->obj_list); + fsnotify_get_mark(mark); + spin_unlock(lock); + fsnotify_destroy_mark(mark, mark->group); fsnotify_put_mark(mark); - fsnotify_put_group(group); } } @@ -332,7 +348,7 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, * inode->i_lock */ spin_lock(&mark->lock); - mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE; + mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED; fsnotify_get_group(group); mark->group = group; @@ -438,8 +454,9 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, } mark = list_first_entry(&to_free, struct fsnotify_mark, g_list); fsnotify_get_mark(mark); - fsnotify_destroy_mark_locked(mark, group); + fsnotify_detach_mark(mark); mutex_unlock(&group->mark_mutex); + fsnotify_free_mark(mark); fsnotify_put_mark(mark); } } -- cgit 1.2.3-korg