From patchwork Thu Jan 4 16:47:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 185076 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:7301:6f82:b0:100:9c79:88ff with SMTP id tb2csp5728574dyb; Thu, 4 Jan 2024 08:47:24 -0800 (PST) X-Google-Smtp-Source: AGHT+IEHVYjXdgHY9tfTOCMVN269yUawN1z69te/F1oqYTNSuBb/zhaEFtAxrwsLkBJXmMkBw3Xq X-Received: by 2002:a17:906:c099:b0:a28:61f7:bbdb with SMTP id f25-20020a170906c09900b00a2861f7bbdbmr431022ejz.71.1704386844156; Thu, 04 Jan 2024 08:47:24 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1704386844; cv=none; d=google.com; s=arc-20160816; b=QOcXPoG4ammq9OTmhGjp8yBHdSNRunOya/cgrNfK6vQSuWwD7LXV+uM66bFmxUQOdG ZvGOe+sTbeoJjhkbkhC96UkXsKSTQe31bMcxrF3JdUsdZST1V9pUQdLxzFmGLQ2LD3Xx 7iURA2qqIPJg4xCunrmVk3uYSgPTP30GzLyNZocdETmjYAhK5j4K6Wt2KoyHCexAEZQF f/hqFmlEXjzQINhaD18phV4UMNUSMk5zAd4QFIN1RWxTso+DxbzsfLGe854keY2+7A1d sT0cmUqJkhLSrQobZUOq/7Rb7DItKYe8gN9/C0woPG1ZN4VsTJyH1czRjwMpXKPfeYhe CNdQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:list-unsubscribe:list-subscribe:list-id:precedence :references:subject:cc:to:from:date:user-agent:message-id; bh=kktwC1DK8bIiOYcf5J4UpCCiyUwqHTf2poxKrFZciXA=; fh=/1t8Er0uVLnMQuQbNQLR+P/hg4jIusuJDiCLcSsQ/Ok=; b=cohY76YKkd2wsyCnWMRiYrgr3Rfc/v002WfQ6nNU5cV4tCma7PkvidGJayNZdxoQ2A VUtOnh/07u7nF19ES9BHU5l+ewZbpaQG0oFlHT1WWkhJSbrL3E3FWeTLkMIewOXWFIhh oPcsn8H8gWrBPjG3MCe7unyRSYJeyO2r/vsLl7c+kL6Po6Ofqzcnf0dB4mrVeG/2VYr5 g0MbxanOx4qUVpWZSY5Ih+gMsNpLa61S9YbNKjEhSxHzOdFdmN8ReKlGg2Rm1WUpUin4 dO70w2BagkOz1gBdfCOmbhUuJ8GuarRHxp3bAhYmAfC4MOrFxJLPx/Zwb8NOMDOpgbJt LJNQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel+bounces-16962-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-16962-ouuuleilei=gmail.com@vger.kernel.org" Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [147.75.80.249]) by mx.google.com with ESMTPS id x2-20020a170906134200b00a280aead29esi3351821ejb.290.2024.01.04.08.47.23 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jan 2024 08:47:24 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-16962-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel+bounces-16962-ouuuleilei=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-16962-ouuuleilei=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 889FE1F258EE for ; Thu, 4 Jan 2024 16:47:23 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5A2C728DAB; Thu, 4 Jan 2024 16:46:34 +0000 (UTC) X-Original-To: linux-kernel@vger.kernel.org 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 DB933250F1 for ; Thu, 4 Jan 2024 16:46:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6766EC433CA; Thu, 4 Jan 2024 16:46:32 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rLQsc-00000000uJG-1xDI; Thu, 04 Jan 2024 11:47:38 -0500 Message-ID: <20240104164738.327880386@goodmis.org> User-Agent: quilt/0.67 Date: Thu, 04 Jan 2024 11:47:04 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Ajay Kaher , Al Viro , Christian Brauner Subject: [for-next][PATCH 1/3] eventfs: Remove "lookup" parameter from create_dir/file_dentry() References: <20240104164703.808999991@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1787179139298390410 X-GMAIL-MSGID: 1787179139298390410 From: "Steven Rostedt (Google)" The "lookup" parameter is a way to differentiate the call to create_file/dir_dentry() from when it's just a lookup (no need to up the dentry refcount) and accessed via a readdir (need to up the refcount). But reality, it just makes the code more complex. Just up the refcount and let the caller decide to dput() the result or not. Link: https://lore.kernel.org/linux-trace-kernel/20240103102553.17a19cea@gandalf.local.home Link: https://lore.kernel.org/linux-trace-kernel/20240104015435.517502710@goodmis.org Cc: Masami Hiramatsu Cc: Mark Rutland Cc: Mathieu Desnoyers Cc: Linus Torvalds Cc: Ajay Kaher Cc: Al Viro Cc: Christian Brauner Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/event_inode.c | 55 +++++++++++++++------------------------- 1 file changed, 20 insertions(+), 35 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index f0677ea0ec24..c360300fb866 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -390,16 +390,14 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry) * @mode: The mode of the file. * @data: The data to use to set the inode of the file with on open() * @fops: The fops of the file to be created. - * @lookup: If called by the lookup routine, in which case, dput() the created dentry. * * Create a dentry for a file of an eventfs_inode @ei and place it into the - * address located at @e_dentry. If the @e_dentry already has a dentry, then - * just do a dget() on it and return. Otherwise create the dentry and attach it. + * address located at @e_dentry. */ static struct dentry * create_file_dentry(struct eventfs_inode *ei, int idx, struct dentry *parent, const char *name, umode_t mode, void *data, - const struct file_operations *fops, bool lookup) + const struct file_operations *fops) { struct eventfs_attr *attr = NULL; struct dentry **e_dentry = &ei->d_children[idx]; @@ -414,9 +412,7 @@ create_file_dentry(struct eventfs_inode *ei, int idx, } /* If the e_dentry already has a dentry, use it */ if (*e_dentry) { - /* lookup does not need to up the ref count */ - if (!lookup) - dget(*e_dentry); + dget(*e_dentry); mutex_unlock(&eventfs_mutex); return *e_dentry; } @@ -441,13 +437,12 @@ create_file_dentry(struct eventfs_inode *ei, int idx, * way to being freed, don't return it. If e_dentry is NULL * it means it was already freed. */ - if (ei->is_freed) + if (ei->is_freed) { dentry = NULL; - else + } else { dentry = *e_dentry; - /* The lookup does not need to up the dentry refcount */ - if (dentry && !lookup) dget(dentry); + } mutex_unlock(&eventfs_mutex); return dentry; } @@ -465,9 +460,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx, } mutex_unlock(&eventfs_mutex); - if (lookup) - dput(dentry); - return dentry; } @@ -500,13 +492,12 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei) * @pei: The eventfs_inode parent of ei. * @ei: The eventfs_inode to create the directory for * @parent: The dentry of the parent of this directory - * @lookup: True if this is called by the lookup code * * This creates and attaches a directory dentry to the eventfs_inode @ei. */ static struct dentry * create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, - struct dentry *parent, bool lookup) + struct dentry *parent) { struct dentry *dentry = NULL; @@ -518,11 +509,9 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, return NULL; } if (ei->dentry) { - /* If the dentry already has a dentry, use it */ + /* If the eventfs_inode already has a dentry, use it */ dentry = ei->dentry; - /* lookup does not need to up the ref count */ - if (!lookup) - dget(dentry); + dget(dentry); mutex_unlock(&eventfs_mutex); return dentry; } @@ -542,7 +531,7 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, * way to being freed. */ dentry = ei->dentry; - if (dentry && !lookup) + if (dentry) dget(dentry); mutex_unlock(&eventfs_mutex); return dentry; @@ -562,9 +551,6 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, } mutex_unlock(&eventfs_mutex); - if (lookup) - dput(dentry); - return dentry; } @@ -589,8 +575,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, struct eventfs_inode *ei; struct dentry *ei_dentry = NULL; struct dentry *ret = NULL; + struct dentry *d; const char *name = dentry->d_name.name; - bool created = false; umode_t mode; void *data; int idx; @@ -626,13 +612,10 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, ret = simple_lookup(dir, dentry, flags); if (IS_ERR(ret)) goto out; - create_dir_dentry(ei, ei_child, ei_dentry, true); - created = true; - break; - } - - if (created) + d = create_dir_dentry(ei, ei_child, ei_dentry); + dput(d); goto out; + } for (i = 0; i < ei->nr_entries; i++) { entry = &ei->entries[i]; @@ -650,8 +633,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, ret = simple_lookup(dir, dentry, flags); if (IS_ERR(ret)) goto out; - create_file_dentry(ei, i, ei_dentry, name, mode, cdata, - fops, true); + d = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops); + dput(d); break; } } @@ -768,9 +751,10 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) inode_lock(parent->d_inode); list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { - d = create_dir_dentry(ei, ei_child, parent, false); + d = create_dir_dentry(ei, ei_child, parent); if (d) { ret = add_dentries(&dentries, d, cnt); + dput(d); if (ret < 0) break; cnt++; @@ -790,9 +774,10 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) mutex_unlock(&eventfs_mutex); if (r <= 0) continue; - d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false); + d = create_file_dentry(ei, i, parent, name, mode, cdata, fops); if (d) { ret = add_dentries(&dentries, d, cnt); + dput(d); if (ret < 0) break; cnt++;