From df68cf2cb73db7ce348defa02a58799260a5b613 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 2 Apr 2021 10:32:21 +0200 Subject: [PATCH] UPSTREAM: file: let pick_file() tell caller it's done Let pick_file() report back that the fd it was passed exceeded the maximum fd in that fdtable. This allows us to simplify the caller of this helper because it doesn't need to care anymore whether the passed in max_fd is excessive. It can rely on pick_file() telling it that it's past the last valid fd. Cc: Christoph Hellwig Cc: Giuseppe Scrivano Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Change-Id: I0d037a47612154c68b4452d8aa26d5cebcf56107 Signed-off-by: Christian Brauner --- fs/file.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/fs/file.c b/fs/file.c index 5f12dc73923c..24e9227dee1e 100644 --- a/fs/file.c +++ b/fs/file.c @@ -648,18 +648,32 @@ void fd_install(unsigned int fd, struct file *file) EXPORT_SYMBOL(fd_install); +/** + * pick_file - return file associatd with fd + * @files: file struct to retrieve file from + * @fd: file descriptor to retrieve file for + * + * If this functions returns an EINVAL error pointer the fd was beyond the + * current maximum number of file descriptors for that fdtable. + * + * Returns: The file associated with @fd, on error returns an error pointer. + */ static struct file *pick_file(struct files_struct *files, unsigned fd) { - struct file *file = NULL; + struct file *file; struct fdtable *fdt; spin_lock(&files->file_lock); fdt = files_fdtable(files); - if (fd >= fdt->max_fds) + if (fd >= fdt->max_fds) { + file = ERR_PTR(-EINVAL); goto out_unlock; + } file = fdt->fd[fd]; - if (!file) + if (!file) { + file = ERR_PTR(-EBADF); goto out_unlock; + } rcu_assign_pointer(fdt->fd[fd], NULL); __put_unused_fd(files, fd); @@ -676,7 +690,7 @@ int __close_fd(struct files_struct *files, unsigned fd) struct file *file; file = pick_file(files, fd); - if (!file) + if (IS_ERR(file)) return -EBADF; return filp_close(file, files); @@ -717,11 +731,16 @@ static inline void __range_close(struct files_struct *cur_fds, unsigned int fd, struct file *file; file = pick_file(cur_fds, fd++); - if (!file) + if (!IS_ERR(file)) { + /* found a valid file to close */ + filp_close(file, cur_fds); + cond_resched(); continue; + } - filp_close(file, cur_fds); - cond_resched(); + /* beyond the last fd in that table */ + if (PTR_ERR(file) == -EINVAL) + return; } }