Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751800AbcCFM0a (ORCPT ); Sun, 6 Mar 2016 07:26:30 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34422 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751590AbcCFMZ4 (ORCPT ); Sun, 6 Mar 2016 07:25:56 -0500 From: Nicolai Stange To: Greg Kroah-Hartman Cc: "Paul E. McKenney" , Alexander Viro , Jonathan Corbet , Jan Kara , Andrew Morton , Julia Lawall , Gilles Muller , Nicolas Palix , Michal Marek , linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr, Nicolai Stange Subject: [PATCH v5 7/8] debugfs: unproxify files created through debugfs_create_blob() Date: Sun, 6 Mar 2016 13:25:02 +0100 Message-Id: <1457267103-28910-8-git-send-email-nicstange@gmail.com> X-Mailer: git-send-email 2.7.2 In-Reply-To: <1457267103-28910-1-git-send-email-nicstange@gmail.com> References: <1457267103-28910-1-git-send-email-nicstange@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1810 Lines: 52 Currently, the struct file_operations fops_blob associated with files created through the debugfs_create_blob() helpers are not file lifetime aware. Thus, a lifetime managing proxy is created around fops_blob each time such a file is opened which is an unnecessary waste of resources. Implement file lifetime management for the fops_bool file_operations. Namely, make read_file_blob() safe gainst file removals by means of debugfs_use_file_start() and debugfs_use_file_finish(). Make debugfs_create_blob() create its files in non-proxying operation mode by means of debugfs_create_file_unsafe(). Signed-off-by: Nicolai Stange --- fs/debugfs/file.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 4eac1a1..9d4bcd6 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -843,8 +843,15 @@ static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { struct debugfs_blob_wrapper *blob = file->private_data; - return simple_read_from_buffer(user_buf, count, ppos, blob->data, - blob->size); + ssize_t r; + int srcu_idx; + + r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx); + if (likely(!r)) + r = simple_read_from_buffer(user_buf, count, ppos, blob->data, + blob->size); + debugfs_use_file_finish(srcu_idx); + return r; } static const struct file_operations fops_blob = { @@ -881,7 +888,7 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) { - return debugfs_create_file(name, mode, parent, blob, &fops_blob); + return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob); } EXPORT_SYMBOL_GPL(debugfs_create_blob); -- 2.7.2