arm64: alternative: Provide if/else/endif assembler macros
[linux-3.10.git] / fs / file_table.c
index a41f23f..28f02a7 100644 (file)
@@ -36,8 +36,6 @@ struct files_stat_struct files_stat = {
        .max_files = NR_FILE
 };
 
-DEFINE_LGLOCK(files_lglock);
-
 /* SLAB cache for file structures */
 static struct kmem_cache *filp_cachep __read_mostly;
 
@@ -94,8 +92,8 @@ int proc_nr_files(ctl_table *table, int write,
 #endif
 
 /* Find an unused file structure and return a pointer to it.
- * Returns NULL, if there are no more free file structures or
- * we run out of memory.
+ * Returns an error pointer if some error happend e.g. we over file
+ * structures limit, run out of memory or operation is not permitted.
  *
  * Be very careful using this.  You are responsible for
  * getting write access to any mount that you might assign
@@ -107,7 +105,8 @@ struct file *get_empty_filp(void)
 {
        const struct cred *cred = current_cred();
        static long old_max;
-       struct file * f;
+       struct file *f;
+       int error;
 
        /*
         * Privileged users can go above max_files
@@ -122,15 +121,17 @@ struct file *get_empty_filp(void)
        }
 
        f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
-       if (f == NULL)
-               goto fail;
+       if (unlikely(!f))
+               return ERR_PTR(-ENOMEM);
 
        percpu_counter_inc(&nr_files);
        f->f_cred = get_cred(cred);
-       if (security_file_alloc(f))
-               goto fail_sec;
+       error = security_file_alloc(f);
+       if (unlikely(error)) {
+               file_free(f);
+               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);
@@ -144,12 +145,7 @@ over:
                pr_info("VFS: file-max limit %lu reached\n", get_max_files());
                old_max = get_nr_files();
        }
-       goto fail;
-
-fail_sec:
-       file_free(f);
-fail:
-       return NULL;
+       return ERR_PTR(-ENFILE);
 }
 
 /**
@@ -173,10 +169,11 @@ struct file *alloc_file(struct path *path, fmode_t mode,
        struct file *file;
 
        file = get_empty_filp();
-       if (!file)
-               return NULL;
+       if (IS_ERR(file))
+               return file;
 
        file->f_path = *path;
+       file->f_inode = path->dentry->d_inode;
        file->f_mapping = path->dentry->d_inode->i_mapping;
        file->f_mode = mode;
        file->f_op = fop;
@@ -211,10 +208,10 @@ static void drop_file_write_access(struct file *file)
        struct dentry *dentry = file->f_path.dentry;
        struct inode *inode = dentry->d_inode;
 
-       put_write_access(inode);
-
        if (special_file(inode->i_mode))
                return;
+
+       put_write_access(inode);
        if (file_check_writeable(file) != 0)
                return;
        __mnt_drop_write(mnt);
@@ -259,23 +256,21 @@ static void __fput(struct file *file)
                drop_file_write_access(file);
        file->f_path.dentry = NULL;
        file->f_path.mnt = NULL;
+       file->f_inode = NULL;
        file_free(file);
        dput(dentry);
        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));
        }
 }
 
@@ -305,17 +300,15 @@ 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 (unlikely(in_interrupt() || task->flags & PF_KTHREAD)) {
-                       unsigned long flags;
-                       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);
-                       return;
+
+               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))
+                               return;
                }
-               init_task_work(&file->f_u.fu_rcuhead, ____fput);
-               task_work_add(task, &file->f_u.fu_rcuhead, true);
+
+               if (llist_add(&file->f_u.fu_llist, &delayed_fput_list))
+                       schedule_work(&delayed_fput_work);
        }
 }
 
@@ -331,7 +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);
        }
@@ -339,237 +331,14 @@ void __fput_sync(struct file *file)
 
 EXPORT_SYMBOL(fput);
 
-struct file *fget(unsigned int fd)
-{
-       struct file *file;
-       struct files_struct *files = current->files;
-
-       rcu_read_lock();
-       file = fcheck_files(files, fd);
-       if (file) {
-               /* File object ref couldn't be taken */
-               if (file->f_mode & FMODE_PATH ||
-                   !atomic_long_inc_not_zero(&file->f_count))
-                       file = NULL;
-       }
-       rcu_read_unlock();
-
-       return file;
-}
-
-EXPORT_SYMBOL(fget);
-
-struct file *fget_raw(unsigned int fd)
-{
-       struct file *file;
-       struct files_struct *files = current->files;
-
-       rcu_read_lock();
-       file = fcheck_files(files, fd);
-       if (file) {
-               /* File object ref couldn't be taken */
-               if (!atomic_long_inc_not_zero(&file->f_count))
-                       file = NULL;
-       }
-       rcu_read_unlock();
-
-       return file;
-}
-
-EXPORT_SYMBOL(fget_raw);
-
-/*
- * Lightweight file lookup - no refcnt increment if fd table isn't shared.
- *
- * You can use this instead of fget if you satisfy all of the following
- * conditions:
- * 1) You must call fput_light before exiting the syscall and returning control
- *    to userspace (i.e. you cannot remember the returned struct file * after
- *    returning to userspace).
- * 2) You must not call filp_close on the returned struct file * in between
- *    calls to fget_light and fput_light.
- * 3) You must not clone the current task in between the calls to fget_light
- *    and fput_light.
- *
- * The fput_needed flag returned by fget_light should be passed to the
- * corresponding fput_light.
- */
-struct file *fget_light(unsigned int fd, int *fput_needed)
-{
-       struct file *file;
-       struct files_struct *files = current->files;
-
-       *fput_needed = 0;
-       if (atomic_read(&files->count) == 1) {
-               file = fcheck_files(files, fd);
-               if (file && (file->f_mode & FMODE_PATH))
-                       file = NULL;
-       } else {
-               rcu_read_lock();
-               file = fcheck_files(files, fd);
-               if (file) {
-                       if (!(file->f_mode & FMODE_PATH) &&
-                           atomic_long_inc_not_zero(&file->f_count))
-                               *fput_needed = 1;
-                       else
-                               /* Didn't get the reference, someone's freed */
-                               file = NULL;
-               }
-               rcu_read_unlock();
-       }
-
-       return file;
-}
-
-struct file *fget_raw_light(unsigned int fd, int *fput_needed)
-{
-       struct file *file;
-       struct files_struct *files = current->files;
-
-       *fput_needed = 0;
-       if (atomic_read(&files->count) == 1) {
-               file = fcheck_files(files, fd);
-       } else {
-               rcu_read_lock();
-               file = fcheck_files(files, fd);
-               if (file) {
-                       if (atomic_long_inc_not_zero(&file->f_count))
-                               *fput_needed = 1;
-                       else
-                               /* Didn't get the reference, someone's freed */
-                               file = NULL;
-               }
-               rcu_read_unlock();
-       }
-
-       return file;
-}
-
 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(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_drop_write_file(f);
-       } while_file_list_for_each_entry;
-       lg_global_unlock(&files_lglock);
-}
-
 void __init files_init(unsigned long mempages)
 { 
        unsigned long n;
@@ -585,6 +354,5 @@ 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, "files_lglock");
        percpu_counter_init(&nr_files, 0);
 }