Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755161Ab0GGMYO (ORCPT ); Wed, 7 Jul 2010 08:24:14 -0400 Received: from cantor.suse.de ([195.135.220.2]:36188 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754731Ab0GGMYN (ORCPT ); Wed, 7 Jul 2010 08:24:13 -0400 Date: Wed, 7 Jul 2010 22:24:06 +1000 From: Nick Piggin To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Al Viro , Christoph Hellwig , Frank Mayhar , John Stultz , Andi Kleen , Alan Cox , "Eric W. Biederman" , Greg Kroah-Hartman Subject: [patch 1/2] fs: cleanup files_lock locking Message-ID: <20100707122406.GL11732@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10039 Lines: 325 Al, would you consider merging these two patches please? Thanks, Nick -- fs: cleanup files_lock locking Lock tty_files with a new spinlock, tty_files_lock; provide helpers to manipulate the per-sb files list; unexport the files_lock spinlock. Acked-by: Andi Kleen Acked-by: Greg Kroah-Hartman Signed-off-by: Nick Piggin --- drivers/char/pty.c | 6 +++++- drivers/char/tty_io.c | 26 ++++++++++++++++++-------- fs/file_table.c | 42 ++++++++++++++++++------------------------ fs/open.c | 4 ++-- include/linux/fs.h | 7 ++----- include/linux/tty.h | 1 + security/selinux/hooks.c | 4 ++-- 7 files changed, 48 insertions(+), 42 deletions(-) Index: linux-2.6/security/selinux/hooks.c =================================================================== --- linux-2.6.orig/security/selinux/hooks.c +++ linux-2.6/security/selinux/hooks.c @@ -2219,7 +2219,7 @@ static inline void flush_unauthorized_fi tty = get_current_tty(); if (tty) { - file_list_lock(); + spin_lock(&tty_files_lock); if (!list_empty(&tty->tty_files)) { struct inode *inode; @@ -2235,7 +2235,7 @@ static inline void flush_unauthorized_fi drop_tty = 1; } } - file_list_unlock(); + spin_unlock(&tty_files_lock); tty_kref_put(tty); } /* Reset controlling tty. */ Index: linux-2.6/drivers/char/pty.c =================================================================== --- linux-2.6.orig/drivers/char/pty.c +++ linux-2.6/drivers/char/pty.c @@ -650,7 +650,11 @@ static int __ptmx_open(struct inode *ino set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ filp->private_data = tty; - file_move(filp, &tty->tty_files); + + file_sb_list_del(filp); /* __dentry_open has put it on the sb list */ + spin_lock(&tty_files_lock); + list_add(&filp->f_u.fu_list, &tty->tty_files); + spin_unlock(&tty_files_lock); retval = devpts_pty_new(inode, tty->link); if (retval) Index: linux-2.6/drivers/char/tty_io.c =================================================================== --- linux-2.6.orig/drivers/char/tty_io.c +++ linux-2.6/drivers/char/tty_io.c @@ -136,6 +136,9 @@ LIST_HEAD(tty_drivers); /* linked list DEFINE_MUTEX(tty_mutex); EXPORT_SYMBOL(tty_mutex); +/* Spinlock to protect the tty->tty_files list */ +DEFINE_SPINLOCK(tty_files_lock); + static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); ssize_t redirected_tty_write(struct file *, const char __user *, @@ -234,11 +237,11 @@ static int check_tty_count(struct tty_st struct list_head *p; int count = 0; - file_list_lock(); + spin_lock(&tty_files_lock); list_for_each(p, &tty->tty_files) { count++; } - file_list_unlock(); + spin_unlock(&tty_files_lock); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_SLAVE && tty->link && tty->link->count) @@ -517,7 +520,7 @@ static void do_tty_hangup(struct work_st lock_kernel(); check_tty_count(tty, "do_tty_hangup"); - file_list_lock(); + spin_lock(&tty_files_lock); /* This breaks for file handles being sent over AF_UNIX sockets ? */ list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { if (filp->f_op->write == redirected_tty_write) @@ -528,7 +531,7 @@ static void do_tty_hangup(struct work_st tty_fasync(-1, filp, 0); /* can't block */ filp->f_op = &hung_up_tty_fops; } - file_list_unlock(); + spin_unlock(&tty_files_lock); tty_ldisc_hangup(tty); @@ -1419,9 +1422,9 @@ static void release_one_tty(struct work_ tty_driver_kref_put(driver); module_put(driver->owner); - file_list_lock(); + spin_lock(&tty_files_lock); list_del_init(&tty->tty_files); - file_list_unlock(); + spin_unlock(&tty_files_lock); put_pid(tty->pgrp); put_pid(tty->session); @@ -1666,7 +1669,10 @@ int tty_release(struct inode *inode, str * - do_tty_hangup no longer sees this file descriptor as * something that needs to be handled for hangups. */ - file_kill(filp); + spin_lock(&tty_files_lock); + BUG_ON(list_empty(&filp->f_u.fu_list)); + list_del_init(&filp->f_u.fu_list); + spin_unlock(&tty_files_lock); filp->private_data = NULL; /* @@ -1835,7 +1841,11 @@ got_driver: } filp->private_data = tty; - file_move(filp, &tty->tty_files); + BUG_ON(list_empty(&filp->f_u.fu_list)); + file_sb_list_del(filp); /* __dentry_open has put it on the sb list */ + spin_lock(&tty_files_lock); + list_add(&filp->f_u.fu_list, &tty->tty_files); + spin_unlock(&tty_files_lock); check_tty_count(tty, "tty_open"); if (tty->driver->type == TTY_DRIVER_TYPE_PTY && tty->driver->subtype == PTY_TYPE_MASTER) Index: linux-2.6/fs/file_table.c =================================================================== --- linux-2.6.orig/fs/file_table.c +++ linux-2.6/fs/file_table.c @@ -32,8 +32,7 @@ struct files_stat_struct files_stat = { .max_files = NR_FILE }; -/* public. Not pretty! */ -__cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); /* SLAB cache for file structures */ static struct kmem_cache *filp_cachep __read_mostly; @@ -249,7 +248,7 @@ static void __fput(struct file *file) cdev_put(inode->i_cdev); fops_put(file->f_op); put_pid(file->f_owner.pid); - file_kill(file); + file_sb_list_del(file); if (file->f_mode & FMODE_WRITE) drop_file_write_access(file); file->f_path.dentry = NULL; @@ -319,31 +318,29 @@ struct file *fget_light(unsigned int fd, return file; } - void put_filp(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { security_file_free(file); - file_kill(file); + file_sb_list_del(file); file_free(file); } } -void file_move(struct file *file, struct list_head *list) +void file_sb_list_add(struct file *file, struct super_block *sb) { - if (!list) - return; - file_list_lock(); - list_move(&file->f_u.fu_list, list); - file_list_unlock(); + spin_lock(&files_lock); + BUG_ON(!list_empty(&file->f_u.fu_list)); + list_add(&file->f_u.fu_list, &sb->s_files); + spin_unlock(&files_lock); } -void file_kill(struct file *file) +void file_sb_list_del(struct file *file) { if (!list_empty(&file->f_u.fu_list)) { - file_list_lock(); + spin_lock(&files_lock); list_del_init(&file->f_u.fu_list); - file_list_unlock(); + spin_unlock(&files_lock); } } @@ -352,7 +349,7 @@ int fs_may_remount_ro(struct super_block struct file *file; /* Check that no files are currently opened for writing. */ - file_list_lock(); + spin_lock(&files_lock); list_for_each_entry(file, &sb->s_files, f_u.fu_list) { struct inode *inode = file->f_path.dentry->d_inode; @@ -364,10 +361,10 @@ int fs_may_remount_ro(struct super_block if (S_ISREG(inode->i_mode) && (file->f_mode & FMODE_WRITE)) goto too_bad; } - file_list_unlock(); + spin_unlock(&files_lock); return 1; /* Tis' cool bro. */ too_bad: - file_list_unlock(); + spin_unlock(&files_lock); return 0; } @@ -383,7 +380,7 @@ void mark_files_ro(struct super_block *s struct file *f; retry: - file_list_lock(); + spin_lock(&files_lock); list_for_each_entry(f, &sb->s_files, f_u.fu_list) { struct vfsmount *mnt; if (!S_ISREG(f->f_path.dentry->d_inode->i_mode)) @@ -399,16 +396,13 @@ retry: continue; file_release_write(f); mnt = mntget(f->f_path.mnt); - file_list_unlock(); - /* - * This can sleep, so we can't hold - * the file_list_lock() spinlock. - */ + /* This can sleep, so we can't hold the spinlock. */ + spin_unlock(&files_lock); mnt_drop_write(mnt); mntput(mnt); goto retry; } - file_list_unlock(); + spin_unlock(&files_lock); } void __init files_init(unsigned long mempages) Index: linux-2.6/fs/open.c =================================================================== --- linux-2.6.orig/fs/open.c +++ linux-2.6/fs/open.c @@ -675,7 +675,7 @@ static struct file *__dentry_open(struct f->f_path.mnt = mnt; f->f_pos = 0; f->f_op = fops_get(inode->i_fop); - file_move(f, &inode->i_sb->s_files); + file_sb_list_add(f, inode->i_sb); error = security_dentry_open(f, cred); if (error) @@ -721,7 +721,7 @@ cleanup_all: mnt_drop_write(mnt); } } - file_kill(f); + file_sb_list_del(f); f->f_path.dentry = NULL; f->f_path.mnt = NULL; cleanup_file: Index: linux-2.6/include/linux/fs.h =================================================================== --- linux-2.6.orig/include/linux/fs.h +++ linux-2.6/include/linux/fs.h @@ -949,9 +949,6 @@ struct file { unsigned long f_mnt_write_state; #endif }; -extern spinlock_t files_lock; -#define file_list_lock() spin_lock(&files_lock); -#define file_list_unlock() spin_unlock(&files_lock); #define get_file(x) atomic_long_inc(&(x)->f_count) #define fput_atomic(x) atomic_long_add_unless(&(x)->f_count, -1, 1) @@ -2182,8 +2179,8 @@ static inline void insert_inode_hash(str __insert_inode_hash(inode, inode->i_ino); } -extern void file_move(struct file *f, struct list_head *list); -extern void file_kill(struct file *f); +extern void file_sb_list_add(struct file *f, struct super_block *sb); +extern void file_sb_list_del(struct file *f); #ifdef CONFIG_BLOCK struct bio; extern void submit_bio(int, struct bio *); Index: linux-2.6/include/linux/tty.h =================================================================== --- linux-2.6.orig/include/linux/tty.h +++ linux-2.6/include/linux/tty.h @@ -467,6 +467,7 @@ extern struct tty_struct *tty_pair_get_t extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty); extern struct mutex tty_mutex; +extern spinlock_t tty_files_lock; extern void tty_write_unlock(struct tty_struct *tty); extern int tty_write_lock(struct tty_struct *tty, int ndelay); -- 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/