diff options
Diffstat (limited to 'fs/file.c')
| -rw-r--r-- | fs/file.c | 124 |
1 files changed, 58 insertions, 66 deletions
diff --git a/fs/file.c b/fs/file.c index e08e4daccac3..8434e0afecc7 100644 --- a/fs/file.c +++ b/fs/file.c @@ -158,7 +158,7 @@ static int expand_fdtable(struct files_struct *files, unsigned int nr) spin_unlock(&files->file_lock); new_fdt = alloc_fdtable(nr); - /* make sure all __fd_install() have seen resize_in_progress + /* make sure all fd_install() have seen resize_in_progress * or have finished their rcu_read_lock_sched() section. */ if (atomic_read(&files->count) > 1) @@ -181,7 +181,7 @@ static int expand_fdtable(struct files_struct *files, unsigned int nr) rcu_assign_pointer(files->fdt, new_fdt); if (cur_fdt != &files->fdtab) call_rcu(&cur_fdt->rcu, free_fdtable_rcu); - /* coupled with smp_rmb() in __fd_install() */ + /* coupled with smp_rmb() in fd_install() */ smp_wmb(); return 1; } @@ -411,19 +411,6 @@ static struct fdtable *close_files(struct files_struct * files) return fdt; } -struct files_struct *get_files_struct(struct task_struct *task) -{ - struct files_struct *files; - - task_lock(task); - files = task->files; - if (files) - atomic_inc(&files->count); - task_unlock(task); - - return files; -} - void put_files_struct(struct files_struct *files) { if (atomic_dec_and_test(&files->count)) { @@ -436,18 +423,6 @@ void put_files_struct(struct files_struct *files) } } -void reset_files_struct(struct files_struct *files) -{ - struct task_struct *tsk = current; - struct files_struct *old; - - old = tsk->files; - task_lock(tsk); - tsk->files = files; - task_unlock(tsk); - put_files_struct(old); -} - void exit_files(struct task_struct *tsk) { struct files_struct * files = tsk->files; @@ -492,9 +467,9 @@ static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start) /* * allocate a file descriptor, mark it busy. */ -int __alloc_fd(struct files_struct *files, - unsigned start, unsigned end, unsigned flags) +static int alloc_fd(unsigned start, unsigned end, unsigned flags) { + struct files_struct *files = current->files; unsigned int fd; int error; struct fdtable *fdt; @@ -550,14 +525,9 @@ out: return error; } -static int alloc_fd(unsigned start, unsigned flags) -{ - return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags); -} - int __get_unused_fd_flags(unsigned flags, unsigned long nofile) { - return __alloc_fd(current->files, 0, nofile, flags); + return alloc_fd(0, nofile, flags); } int get_unused_fd_flags(unsigned flags) @@ -596,17 +566,13 @@ EXPORT_SYMBOL(put_unused_fd); * It should never happen - if we allow dup2() do it, _really_ bad things * will follow. * - * NOTE: __fd_install() variant is really, really low-level; don't - * use it unless you are forced to by truly lousy API shoved down - * your throat. 'files' *MUST* be either current->files or obtained - * by get_files_struct(current) done by whoever had given it to you, - * or really bad things will happen. Normally you want to use - * fd_install() instead. + * This consumes the "file" refcount, so callers should treat it + * as if they had called fput(file). */ -void __fd_install(struct files_struct *files, unsigned int fd, - struct file *file) +void fd_install(unsigned int fd, struct file *file) { + struct files_struct *files = current->files; struct fdtable *fdt; rcu_read_lock_sched(); @@ -628,15 +594,6 @@ void __fd_install(struct files_struct *files, unsigned int fd, rcu_read_unlock_sched(); } -/* - * This consumes the "file" refcount, so callers should treat it - * as if they had called fput(file). - */ -void fd_install(unsigned int fd, struct file *file) -{ - __fd_install(current->files, fd, file); -} - EXPORT_SYMBOL(fd_install); static struct file *pick_file(struct files_struct *files, unsigned fd) @@ -659,11 +616,9 @@ out_unlock: return file; } -/* - * The same warnings as for __alloc_fd()/__fd_install() apply here... - */ -int __close_fd(struct files_struct *files, unsigned fd) +int close_fd(unsigned fd) { + struct files_struct *files = current->files; struct file *file; file = pick_file(files, fd); @@ -672,7 +627,7 @@ int __close_fd(struct files_struct *files, unsigned fd) return filp_close(file, files); } -EXPORT_SYMBOL(__close_fd); /* for ksys_close() */ +EXPORT_SYMBOL(close_fd); /* for ksys_close() */ static inline void __range_cloexec(struct files_struct *cur_fds, unsigned int fd, unsigned int max_fd) @@ -777,11 +732,11 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) } /* - * variant of __close_fd that gets a ref on the file for later fput. + * variant of close_fd that gets a ref on the file for later fput. * The caller must ensure that filp_close() called on the file, and then * an fput(). */ -int __close_fd_get_file(unsigned int fd, struct file **res) +int close_fd_get_file(unsigned int fd, struct file **res) { struct files_struct *files = current->files; struct file *file; @@ -850,7 +805,7 @@ static struct file *__fget_files(struct files_struct *files, unsigned int fd, rcu_read_lock(); loop: - file = fcheck_files(files, fd); + file = files_lookup_fd_rcu(files, fd); if (file) { /* File object ref couldn't be taken. * dup2() atomicity guarantee is the reason @@ -901,6 +856,42 @@ struct file *fget_task(struct task_struct *task, unsigned int fd) return file; } +struct file *task_lookup_fd_rcu(struct task_struct *task, unsigned int fd) +{ + /* Must be called with rcu_read_lock held */ + struct files_struct *files; + struct file *file = NULL; + + task_lock(task); + files = task->files; + if (files) + file = files_lookup_fd_rcu(files, fd); + task_unlock(task); + + return file; +} + +struct file *task_lookup_next_fd_rcu(struct task_struct *task, unsigned int *ret_fd) +{ + /* Must be called with rcu_read_lock held */ + struct files_struct *files; + unsigned int fd = *ret_fd; + struct file *file = NULL; + + task_lock(task); + files = task->files; + if (files) { + for (; fd < files_fdtable(files)->max_fds; fd++) { + file = files_lookup_fd_rcu(files, fd); + if (file) + break; + } + } + task_unlock(task); + *ret_fd = fd; + return file; +} + /* * Lightweight file lookup - no refcnt increment if fd table isn't shared. * @@ -923,7 +914,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) struct file *file; if (atomic_read(&files->count) == 1) { - file = __fcheck_files(files, fd); + file = files_lookup_fd_raw(files, fd); if (!file || unlikely(file->f_mode & mask)) return 0; return (unsigned long)file; @@ -1045,7 +1036,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags) struct files_struct *files = current->files; if (!file) - return __close_fd(files, fd); + return close_fd(fd); if (fd >= rlimit(RLIMIT_NOFILE)) return -EBADF; @@ -1134,7 +1125,7 @@ static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags) spin_lock(&files->file_lock); err = expand_files(files, newfd); - file = fcheck(oldfd); + file = files_lookup_fd_locked(files, oldfd); if (unlikely(!file)) goto Ebadf; if (unlikely(err < 0)) { @@ -1163,7 +1154,7 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) int retval = oldfd; rcu_read_lock(); - if (!fcheck_files(files, oldfd)) + if (!files_lookup_fd_rcu(files, oldfd)) retval = -EBADF; rcu_read_unlock(); return retval; @@ -1188,10 +1179,11 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes) int f_dupfd(unsigned int from, struct file *file, unsigned flags) { + unsigned long nofile = rlimit(RLIMIT_NOFILE); int err; - if (from >= rlimit(RLIMIT_NOFILE)) + if (from >= nofile) return -EINVAL; - err = alloc_fd(from, flags); + err = alloc_fd(from, nofile, flags); if (err >= 0) { get_file(file); fd_install(err, file); |