From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98432138D for ; Tue, 3 Jan 2023 08:15:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B1B1C433D2; Tue, 3 Jan 2023 08:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1672733753; bh=NinGCVOC9xKRlCNOLVMTHzJOhxCFZn+947TRj4iAUdA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uVehDNE27QpJvgV9V3YEsR9T1Pt2sxozXsPlYCFq9/TkTAJi3SvVx0VhfWXtLtgHQ Kp8/1JP4zPmwMjfxNZy51rqCaEFVZogKNjSqGnK9yOdJYlxwkBVV7st531r6e0o7iv quUOdDjd1Nt2CSGEmDFP5XrrGynMvzWTtLjdF0CE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jens Axboe Subject: [PATCH 5.10 14/63] fs: provide locked helper variant of close_fd_get_file() Date: Tue, 3 Jan 2023 09:13:44 +0100 Message-Id: <20230103081309.418857619@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230103081308.548338576@linuxfoundation.org> References: <20230103081308.548338576@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jens Axboe [ Upstream commit 53dec2ea74f2ef360e8455439be96a780baa6097 ] Assumes current->files->file_lock is already held on invocation. Helps the caller check the file before removing the fd, if it needs to. Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/file.c | 36 +++++++++++++++++++++++++----------- fs/internal.h | 1 + 2 files changed, 26 insertions(+), 11 deletions(-) --- a/fs/file.c +++ b/fs/file.c @@ -22,6 +22,8 @@ #include #include +#include "internal.h" + unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; /* our min() is unusable in constant expressions ;-/ */ @@ -780,36 +782,48 @@ int __close_range(unsigned fd, unsigned } /* - * 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(). + * See close_fd_get_file() below, this variant assumes current->files->file_lock + * is held. */ -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; struct fdtable *fdt; - spin_lock(&files->file_lock); fdt = files_fdtable(files); if (fd >= fdt->max_fds) - goto out_unlock; + goto out_err; file = fdt->fd[fd]; if (!file) - goto out_unlock; + goto out_err; rcu_assign_pointer(fdt->fd[fd], NULL); __put_unused_fd(files, fd); - spin_unlock(&files->file_lock); get_file(file); *res = file; return 0; - -out_unlock: - spin_unlock(&files->file_lock); +out_err: *res = NULL; return -ENOENT; } +/* + * 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) +{ + struct files_struct *files = current->files; + int ret; + + spin_lock(&files->file_lock); + ret = __close_fd_get_file(fd, res); + spin_unlock(&files->file_lock); + + return ret; +} + void do_close_on_exec(struct files_struct *files) { unsigned i; --- a/fs/internal.h +++ b/fs/internal.h @@ -134,6 +134,7 @@ extern struct file *do_file_open_root(st const char *, const struct open_flags *); extern struct open_how build_open_how(int flags, umode_t mode); extern int build_open_flags(const struct open_how *how, struct open_flags *op); +extern int __close_fd_get_file(unsigned int fd, struct file **res); long do_sys_ftruncate(unsigned int fd, loff_t length, int small); int chmod_common(const struct path *path, umode_t mode);