From c77cecee52e9b599da1f8ffd9170d4374c99a345 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 13 Jun 2013 23:37:49 +0100 Subject: Replace a bunch of file->dentry->d_inode refs with file_inode() Replace a bunch of file->dentry->d_inode refs with file_inode(). In __fput(), use file->f_inode instead so as not to be affected by any tricks that file_inode() might grow. Signed-off-by: David Howells Signed-off-by: Al Viro --- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/file_table.c') diff --git a/fs/file_table.c b/fs/file_table.c index 485dc0eddd6..08e719b884c 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -227,7 +227,7 @@ static void __fput(struct file *file) { struct dentry *dentry = file->f_path.dentry; struct vfsmount *mnt = file->f_path.mnt; - struct inode *inode = dentry->d_inode; + struct inode *inode = file->f_inode; might_sleep(); -- cgit v1.2.3-70-g09d2 From 64372501e2af9b11e2ffd1ff79345dc4b1abe539 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Mon, 8 Jul 2013 14:24:15 -0700 Subject: fs/file_table.c:fput(): add comment A missed update to "fput: task_work_add() can fail if the caller has passed exit_task_work()". Cc: "Eric W. Biederman" Cc: Al Viro Cc: Andrey Vagin Cc: David Howells Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/file_table.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/file_table.c') diff --git a/fs/file_table.c b/fs/file_table.c index 08e719b884c..b9a77ad08b4 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -313,6 +313,12 @@ void fput(struct file *file) init_task_work(&file->f_u.fu_rcuhead, ____fput); if (!task_work_add(task, &file->f_u.fu_rcuhead, true)) return; + /* + * After this task has run exit_task_work(), + * task_work_add() will fail. free_ipc_ns()-> + * shm_destroy() can do this. Fall through to delayed + * fput to avoid leaking *file. + */ } spin_lock_irqsave(&delayed_fput_lock, flags); list_add(&file->f_u.fu_list, &delayed_fput_list); -- cgit v1.2.3-70-g09d2 From 4f5e65a1cc90bbb15b9f6cdc362922af1bcc155a Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 8 Jul 2013 14:24:16 -0700 Subject: fput: turn "list_head delayed_fput_list" into llist_head fput() and delayed_fput() can use llist and avoid the locking. This is unlikely path, it is not that this change can improve the performance, but this way the code looks simpler. Signed-off-by: Oleg Nesterov Suggested-by: Andrew Morton Cc: Al Viro Cc: Andrey Vagin Cc: "Eric W. Biederman" Cc: David Howells Cc: Huang Ying Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/file_table.c | 25 ++++++++++--------------- include/linux/fs.h | 2 ++ 2 files changed, 12 insertions(+), 15 deletions(-) (limited to 'fs/file_table.c') diff --git a/fs/file_table.c b/fs/file_table.c index b9a77ad08b4..b44e4c55978 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -265,18 +265,15 @@ static void __fput(struct file *file) mntput(mnt); } -static DEFINE_SPINLOCK(delayed_fput_lock); -static LIST_HEAD(delayed_fput_list); +static LLIST_HEAD(delayed_fput_list); static void delayed_fput(struct work_struct *unused) { - LIST_HEAD(head); - spin_lock_irq(&delayed_fput_lock); - list_splice_init(&delayed_fput_list, &head); - spin_unlock_irq(&delayed_fput_lock); - while (!list_empty(&head)) { - struct file *f = list_first_entry(&head, struct file, f_u.fu_list); - list_del_init(&f->f_u.fu_list); - __fput(f); + struct llist_node *node = llist_del_all(&delayed_fput_list); + struct llist_node *next; + + for (; node; node = next) { + next = llist_next(node); + __fput(llist_entry(node, struct file, f_u.fu_llist)); } } @@ -306,7 +303,6 @@ void fput(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { struct task_struct *task = current; - unsigned long flags; file_sb_list_del(file); if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -320,10 +316,9 @@ void fput(struct file *file) * fput to avoid leaking *file. */ } - spin_lock_irqsave(&delayed_fput_lock, flags); - list_add(&file->f_u.fu_list, &delayed_fput_list); - schedule_work(&delayed_fput_work); - spin_unlock_irqrestore(&delayed_fput_lock, flags); + + if (llist_add(&file->f_u.fu_llist, &delayed_fput_list)) + schedule_work(&delayed_fput_work); } } diff --git a/include/linux/fs.h b/include/linux/fs.h index 834c9e5113d..d40e8e78bbd 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -768,6 +769,7 @@ struct file { */ union { struct list_head fu_list; + struct llist_node fu_llist; struct rcu_head fu_rcuhead; } f_u; struct path f_path; -- cgit v1.2.3-70-g09d2