Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966494AbcCPISw (ORCPT ); Wed, 16 Mar 2016 04:18:52 -0400 Received: from mail.kernel.org ([198.145.29.136]:60579 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965852AbcCPIMe (ORCPT ); Wed, 16 Mar 2016 04:12:34 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Al Viro , Zefan Li Subject: [PATCH 3.4 090/107] get rid of s_files and files_lock Date: Wed, 16 Mar 2016 16:06:24 +0800 Message-Id: <1458115601-5762-90-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1458115541-5712-1-git-send-email-lizf@kernel.org> References: <1458115541-5712-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8508 Lines: 318 From: Al Viro 3.4.111-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit eee5cc2702929fd41cce28058dc6d6717f723f87 upstream. The only thing we need it for is alt-sysrq-r (emergency remount r/o) and these days we can do just as well without going through the list of files. Signed-off-by: Al Viro [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li --- fs/file_table.c | 130 ----------------------------------------------------- fs/internal.h | 3 -- fs/open.c | 2 - fs/super.c | 21 +-------- include/linux/fs.h | 13 ------ 5 files changed, 2 insertions(+), 167 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index 70f2a0f..a01710a 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -34,9 +34,6 @@ struct files_stat_struct files_stat = { .max_files = NR_FILE }; -DECLARE_LGLOCK(files_lglock); -DEFINE_LGLOCK(files_lglock); - /* SLAB cache for file structures */ static struct kmem_cache *filp_cachep __read_mostly; @@ -129,7 +126,6 @@ struct file *get_empty_filp(void) if (security_file_alloc(f)) goto fail_sec; - INIT_LIST_HEAD(&f->f_u.fu_list); atomic_long_set(&f->f_count, 1); rwlock_init(&f->f_owner.lock); spin_lock_init(&f->f_lock); @@ -252,7 +248,6 @@ static void __fput(struct file *file) } fops_put(file->f_op); put_pid(file->f_owner.pid); - file_sb_list_del(file); if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) i_readcount_dec(inode); if (file->f_mode & FMODE_WRITE) @@ -382,134 +377,10 @@ void put_filp(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { security_file_free(file); - file_sb_list_del(file); file_free(file); } } -static inline int file_list_cpu(struct file *file) -{ -#ifdef CONFIG_SMP - return file->f_sb_list_cpu; -#else - return smp_processor_id(); -#endif -} - -/* helper for file_sb_list_add to reduce ifdefs */ -static inline void __file_sb_list_add(struct file *file, struct super_block *sb) -{ - struct list_head *list; -#ifdef CONFIG_SMP - int cpu; - cpu = smp_processor_id(); - file->f_sb_list_cpu = cpu; - list = per_cpu_ptr(sb->s_files, cpu); -#else - list = &sb->s_files; -#endif - list_add(&file->f_u.fu_list, list); -} - -/** - * file_sb_list_add - add a file to the sb's file list - * @file: file to add - * @sb: sb to add it to - * - * Use this function to associate a file with the superblock of the inode it - * refers to. - */ -void file_sb_list_add(struct file *file, struct super_block *sb) -{ - lg_local_lock(files_lglock); - __file_sb_list_add(file, sb); - lg_local_unlock(files_lglock); -} - -/** - * file_sb_list_del - remove a file from the sb's file list - * @file: file to remove - * @sb: sb to remove it from - * - * Use this function to remove a file from its superblock. - */ -void file_sb_list_del(struct file *file) -{ - if (!list_empty(&file->f_u.fu_list)) { - lg_local_lock_cpu(files_lglock, file_list_cpu(file)); - list_del_init(&file->f_u.fu_list); - lg_local_unlock_cpu(files_lglock, file_list_cpu(file)); - } -} - -#ifdef CONFIG_SMP - -/* - * These macros iterate all files on all CPUs for a given superblock. - * files_lglock must be held globally. - */ -#define do_file_list_for_each_entry(__sb, __file) \ -{ \ - int i; \ - for_each_possible_cpu(i) { \ - struct list_head *list; \ - list = per_cpu_ptr((__sb)->s_files, i); \ - list_for_each_entry((__file), list, f_u.fu_list) - -#define while_file_list_for_each_entry \ - } \ -} - -#else - -#define do_file_list_for_each_entry(__sb, __file) \ -{ \ - struct list_head *list; \ - list = &(sb)->s_files; \ - list_for_each_entry((__file), list, f_u.fu_list) - -#define while_file_list_for_each_entry \ -} - -#endif - -/** - * mark_files_ro - mark all files read-only - * @sb: superblock in question - * - * All files are marked read-only. We don't care about pending - * delete files so this should be used in 'force' mode only. - */ -void mark_files_ro(struct super_block *sb) -{ - struct file *f; - -retry: - lg_global_lock(files_lglock); - do_file_list_for_each_entry(sb, f) { - struct vfsmount *mnt; - if (!S_ISREG(f->f_path.dentry->d_inode->i_mode)) - continue; - if (!file_count(f)) - continue; - if (!(f->f_mode & FMODE_WRITE)) - continue; - spin_lock(&f->f_lock); - f->f_mode &= ~FMODE_WRITE; - spin_unlock(&f->f_lock); - if (file_check_writeable(f) != 0) - continue; - file_release_write(f); - mnt = mntget(f->f_path.mnt); - /* This can sleep, so we can't hold the spinlock. */ - lg_global_unlock(files_lglock); - mnt_drop_write(mnt); - mntput(mnt); - goto retry; - } while_file_list_for_each_entry; - lg_global_unlock(files_lglock); -} - void __init files_init(unsigned long mempages) { unsigned long n; @@ -525,6 +396,5 @@ void __init files_init(unsigned long mempages) n = (mempages * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = max_t(unsigned long, n, NR_FILE); files_defer_init(); - lg_lock_init(files_lglock); percpu_counter_init(&nr_files, 0); } diff --git a/fs/internal.h b/fs/internal.h index 9962c59..ed005c5 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -67,9 +67,6 @@ extern void chroot_fs_refs(struct path *, struct path *); /* * file_table.c */ -extern void file_sb_list_add(struct file *f, struct super_block *sb); -extern void file_sb_list_del(struct file *f); -extern void mark_files_ro(struct super_block *); extern struct file *get_empty_filp(void); /* diff --git a/fs/open.c b/fs/open.c index cf1d34f..703b051 100644 --- a/fs/open.c +++ b/fs/open.c @@ -672,7 +672,6 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, f->f_path.dentry = dentry; f->f_path.mnt = mnt; f->f_pos = 0; - file_sb_list_add(f, inode->i_sb); if (unlikely(f->f_mode & FMODE_PATH)) { f->f_op = &empty_fops; @@ -730,7 +729,6 @@ cleanup_all: mnt_drop_write(mnt); } } - file_sb_list_del(f); f->f_path.dentry = NULL; f->f_path.mnt = NULL; cleanup_file: diff --git a/fs/super.c b/fs/super.c index d0154e5..36fbe27 100644 --- a/fs/super.c +++ b/fs/super.c @@ -122,22 +122,7 @@ static struct super_block *alloc_super(struct file_system_type *type) s = NULL; goto out; } -#ifdef CONFIG_SMP - s->s_files = alloc_percpu(struct list_head); - if (!s->s_files) { - security_sb_free(s); - kfree(s); - s = NULL; - goto out; - } else { - int i; - for_each_possible_cpu(i) - INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i)); - } -#else - INIT_LIST_HEAD(&s->s_files); -#endif s->s_bdi = &default_backing_dev_info; INIT_HLIST_NODE(&s->s_instances); INIT_HLIST_BL_HEAD(&s->s_anon); @@ -200,9 +185,6 @@ out: */ static inline void destroy_super(struct super_block *s) { -#ifdef CONFIG_SMP - free_percpu(s->s_files); -#endif security_sb_free(s); WARN_ON(!list_empty(&s->s_mounts)); kfree(s->s_subtype); @@ -744,7 +726,8 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force) make sure there are no rw files opened */ if (remount_ro) { if (force) { - mark_files_ro(sb); + sb->s_readonly_remount = 1; + smp_wmb(); } else { retval = sb_prepare_remount_readonly(sb); if (retval) diff --git a/include/linux/fs.h b/include/linux/fs.h index 210c347..e7bbe99 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -976,12 +976,7 @@ static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index) #define FILE_MNT_WRITE_RELEASED 2 struct file { - /* - * fu_list becomes invalid after file_free is called and queued via - * fu_rcuhead for RCU freeing - */ union { - struct list_head fu_list; struct rcu_head fu_rcuhead; } f_u; struct path f_path; @@ -994,9 +989,6 @@ struct file { * Must not be taken from IRQ context. */ spinlock_t f_lock; -#ifdef CONFIG_SMP - int f_sb_list_cpu; -#endif atomic_long_t f_count; unsigned int f_flags; fmode_t f_mode; @@ -1443,11 +1435,6 @@ struct super_block { struct list_head s_inodes; /* all inodes */ struct hlist_bl_head s_anon; /* anonymous dentries for (nfs) exporting */ -#ifdef CONFIG_SMP - struct list_head __percpu *s_files; -#else - struct list_head s_files; -#endif struct list_head s_mounts; /* list of mounts; _not_ for fs use */ /* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */ struct list_head s_dentry_lru; /* unused dentry lru */ -- 1.9.1