diff options
Diffstat (limited to 'fs/file.c')
-rw-r--r-- | fs/file.c | 98 |
1 files changed, 29 insertions, 69 deletions
diff --git a/fs/file.c b/fs/file.c index 4a78f981557..771578b33fb 100644 --- a/fs/file.c +++ b/fs/file.c @@ -348,21 +348,16 @@ out: return NULL; } -static void close_files(struct files_struct * files) +static struct fdtable *close_files(struct files_struct * files) { - int i, j; - struct fdtable *fdt; - - j = 0; - /* * It is safe to dereference the fd table without RCU or * ->file_lock because this is the last reference to the - * files structure. But use RCU to shut RCU-lockdep up. + * files structure. */ - rcu_read_lock(); - fdt = files_fdtable(files); - rcu_read_unlock(); + struct fdtable *fdt = rcu_dereference_raw(files->fdt); + int i, j = 0; + for (;;) { unsigned long set; i = j * BITS_PER_LONG; @@ -381,6 +376,8 @@ static void close_files(struct files_struct * files) set >>= 1; } } + + return fdt; } struct files_struct *get_files_struct(struct task_struct *task) @@ -398,14 +395,9 @@ struct files_struct *get_files_struct(struct task_struct *task) void put_files_struct(struct files_struct *files) { - struct fdtable *fdt; - if (atomic_dec_and_test(&files->count)) { - close_files(files); - /* not really needed, since nobody can see us */ - rcu_read_lock(); - fdt = files_fdtable(files); - rcu_read_unlock(); + struct fdtable *fdt = close_files(files); + /* free the arrays if they are not embedded */ if (fdt != &files->fdtab) __free_fdtable(fdt); @@ -645,16 +637,16 @@ void do_close_on_exec(struct files_struct *files) spin_unlock(&files->file_lock); } -struct file *fget(unsigned int fd) +static struct file *__fget(unsigned int fd, fmode_t mask) { - struct file *file; struct files_struct *files = current->files; + struct file *file; rcu_read_lock(); file = fcheck_files(files, fd); if (file) { /* File object ref couldn't be taken */ - if (file->f_mode & FMODE_PATH || + if ((file->f_mode & mask) || !atomic_long_inc_not_zero(&file->f_count)) file = NULL; } @@ -663,25 +655,16 @@ struct file *fget(unsigned int fd) return file; } +struct file *fget(unsigned int fd) +{ + return __fget(fd, FMODE_PATH); +} 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; + return __fget(fd, 0); } - EXPORT_SYMBOL(fget_raw); /* @@ -700,56 +683,33 @@ EXPORT_SYMBOL(fget_raw); * 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 *__fget_light(unsigned int fd, fmode_t mask, int *fput_needed) { - struct file *file; struct files_struct *files = current->files; + struct file *file; *fput_needed = 0; if (atomic_read(&files->count) == 1) { - file = fcheck_files(files, fd); - if (file && (file->f_mode & FMODE_PATH)) + file = __fcheck_files(files, fd); + if (file && (file->f_mode & mask)) 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(); + file = __fget(fd, mask); + if (file) + *fput_needed = 1; } return file; } +struct file *fget_light(unsigned int fd, int *fput_needed) +{ + return __fget_light(fd, FMODE_PATH, fput_needed); +} EXPORT_SYMBOL(fget_light); 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; + return __fget_light(fd, 0, fput_needed); } void set_close_on_exec(unsigned int fd, int flag) |