--- /dev/null
+From 4f5e65a1cc90bbb15b9f6cdc362922af1bcc155a Mon Sep 17 00:00:00 2001
+From: Oleg Nesterov <oleg@redhat.com>
+Date: Mon, 8 Jul 2013 14:24:16 -0700
+Subject: fput: turn "list_head delayed_fput_list" into llist_head
+
+From: Oleg Nesterov <oleg@redhat.com>
+
+commit 4f5e65a1cc90bbb15b9f6cdc362922af1bcc155a upstream.
+
+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 <oleg@redhat.com>
+Suggested-by: Andrew Morton <akpm@linux-foundation.org>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Cc: Andrey Vagin <avagin@openvz.org>
+Cc: "Eric W. Biederman" <ebiederm@xmission.com>
+Cc: David Howells <dhowells@redhat.com>
+Cc: Huang Ying <ying.huang@intel.com>
+Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: Wang Kai <morgan.wang@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/file_table.c | 25 ++++++++++---------------
+ include/linux/fs.h | 2 ++
+ 2 files changed, 12 insertions(+), 15 deletions(-)
+
+--- 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))) {
+@@ -314,10 +310,9 @@ void fput(struct file *file)
+ if (!task_work_add(task, &file->f_u.fu_rcuhead, true))
+ return;
+ }
+- 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);
+ }
+ }
+
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -10,6 +10,7 @@
+ #include <linux/stat.h>
+ #include <linux/cache.h>
+ #include <linux/list.h>
++#include <linux/llist.h>
+ #include <linux/radix-tree.h>
+ #include <linux/rbtree.h>
+ #include <linux/init.h>
+@@ -767,6 +768,7 @@ struct file {
+ */
+ union {
+ struct list_head fu_list;
++ struct llist_node fu_llist;
+ struct rcu_head fu_rcuhead;
+ } f_u;
+ struct path f_path;
--- /dev/null
+From eee5cc2702929fd41cce28058dc6d6717f723f87 Mon Sep 17 00:00:00 2001
+From: Al Viro <viro@zeniv.linux.org.uk>
+Date: Fri, 4 Oct 2013 11:06:42 -0400
+Subject: get rid of s_files and files_lock
+
+From: Al Viro <viro@zeniv.linux.org.uk>
+
+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 <viro@zeniv.linux.org.uk>
+[wangkai: backport to 3.10: adjust context]
+Signed-off-by: Wang Kai <morgan.wang@huawei.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/file_table.c | 123 -----------------------------------------------------
+ fs/internal.h | 3 -
+ fs/open.c | 2
+ fs/super.c | 23 ---------
+ include/linux/fs.h | 13 -----
+ 5 files changed, 2 insertions(+), 162 deletions(-)
+
+--- a/fs/file_table.c
++++ b/fs/file_table.c
+@@ -36,8 +36,6 @@ struct files_stat_struct files_stat = {
+ .max_files = NR_FILE
+ };
+
+-DEFINE_STATIC_LGLOCK(files_lglock);
+-
+ /* SLAB cache for file structures */
+ static struct kmem_cache *filp_cachep __read_mostly;
+
+@@ -134,7 +132,6 @@ struct file *get_empty_filp(void)
+ return ERR_PTR(error);
+ }
+
+- 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);
+@@ -304,7 +301,6 @@ void fput(struct file *file)
+ if (atomic_long_dec_and_test(&file->f_count)) {
+ struct task_struct *task = current;
+
+- file_sb_list_del(file);
+ if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
+ init_task_work(&file->f_u.fu_rcuhead, ____fput);
+ if (!task_work_add(task, &file->f_u.fu_rcuhead, true))
+@@ -328,7 +324,6 @@ void __fput_sync(struct file *file)
+ {
+ if (atomic_long_dec_and_test(&file->f_count)) {
+ struct task_struct *task = current;
+- file_sb_list_del(file);
+ BUG_ON(!(task->flags & PF_KTHREAD));
+ __fput(file);
+ }
+@@ -340,127 +335,10 @@ 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;
+-
+- lg_global_lock(&files_lglock);
+- do_file_list_for_each_entry(sb, f) {
+- if (!S_ISREG(file_inode(f)->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;
+- __mnt_drop_write(f->f_path.mnt);
+- file_release_write(f);
+- } while_file_list_for_each_entry;
+- lg_global_unlock(&files_lglock);
+-}
+-
+ void __init files_init(unsigned long mempages)
+ {
+ unsigned long n;
+@@ -476,6 +354,5 @@ void __init files_init(unsigned long mem
+ 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, "files_lglock");
+ percpu_counter_init(&nr_files, 0);
+ }
+--- a/fs/internal.h
++++ b/fs/internal.h
+@@ -74,9 +74,6 @@ extern void chroot_fs_refs(const struct
+ /*
+ * 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);
+
+ /*
+--- a/fs/open.c
++++ b/fs/open.c
+@@ -674,7 +674,6 @@ static int do_dentry_open(struct file *f
+ }
+
+ f->f_mapping = inode->i_mapping;
+- file_sb_list_add(f, inode->i_sb);
+
+ if (unlikely(f->f_mode & FMODE_PATH)) {
+ f->f_op = &empty_fops;
+@@ -709,7 +708,6 @@ static int do_dentry_open(struct file *f
+
+ cleanup_all:
+ fops_put(f->f_op);
+- file_sb_list_del(f);
+ if (f->f_mode & FMODE_WRITE) {
+ if (!special_file(inode->i_mode)) {
+ /*
+--- a/fs/super.c
++++ b/fs/super.c
+@@ -163,19 +163,6 @@ static struct super_block *alloc_super(s
+ s = NULL;
+ goto out;
+ }
+-#ifdef CONFIG_SMP
+- s->s_files = alloc_percpu(struct list_head);
+- if (!s->s_files)
+- goto err_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
+ if (init_sb_writers(s, type))
+ goto err_out;
+ s->s_flags = flags;
+@@ -225,10 +212,6 @@ out:
+ return s;
+ err_out:
+ security_sb_free(s);
+-#ifdef CONFIG_SMP
+- if (s->s_files)
+- free_percpu(s->s_files);
+-#endif
+ destroy_sb_writers(s);
+ kfree(s);
+ s = NULL;
+@@ -243,9 +226,6 @@ err_out:
+ */
+ static inline void destroy_super(struct super_block *s)
+ {
+-#ifdef CONFIG_SMP
+- free_percpu(s->s_files);
+-#endif
+ destroy_sb_writers(s);
+ security_sb_free(s);
+ WARN_ON(!list_empty(&s->s_mounts));
+@@ -727,7 +707,8 @@ int do_remount_sb(struct super_block *sb
+ 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)
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -762,12 +762,7 @@ static inline int ra_has_index(struct fi
+ #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 llist_node fu_llist;
+ struct rcu_head fu_rcuhead;
+ } f_u;
+@@ -781,9 +776,6 @@ 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;
+@@ -1259,11 +1251,6 @@ 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 */
projects / thirdparty / kernel / stable-queue.git / commitdiff
