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From: "Mickaël Salaün" <mic@digikod.net>
To: James Morris <jmorris@namei.org>, Jann Horn <jannh@google.com>,
	"Serge E . Hallyn" <serge@hallyn.com>
Cc: "Mickaël Salaün" <mic@digikod.net>,
	"Shuah Khan" <shuah@kernel.org>,
	"Vincent Dagonneau" <vincent.dagonneau@ssi.gouv.fr>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	linux-security-module@vger.kernel.org
Subject: [PATCH v1 2/9] landlock: Cosmetic fixes for filesystem management
Date: Wed, 11 Nov 2020 22:34:35 +0100	[thread overview]
Message-ID: <20201111213442.434639-3-mic@digikod.net> (raw)
In-Reply-To: <20201111213442.434639-1-mic@digikod.net>

Improve comments and make get_inode_object() more readable.  The kfree()
call is correct but we should mimimize as much as possible lock windows.

Cc: James Morris <jmorris@namei.org>
Cc: Jann Horn <jannh@google.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
---
 security/landlock/fs.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index b67c821bb40b..33fc7ae17c7f 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -85,8 +85,8 @@ static struct landlock_object *get_inode_object(struct inode *const inode)
 			return object;
 		}
 		/*
-		 * We're racing with release_inode(), the object is going away.
-		 * Wait for release_inode(), then retry.
+		 * We are racing with release_inode(), the object is going
+		 * away.  Wait for release_inode(), then retry.
 		 */
 		spin_lock(&object->lock);
 		spin_unlock(&object->lock);
@@ -107,21 +107,21 @@ static struct landlock_object *get_inode_object(struct inode *const inode)
 			lockdep_is_held(&inode->i_lock));
 	if (unlikely(object)) {
 		/* Someone else just created the object, bail out and retry. */
-		kfree(new_object);
 		spin_unlock(&inode->i_lock);
+		kfree(new_object);
 
 		rcu_read_lock();
 		goto retry;
-	} else {
-		rcu_assign_pointer(inode_sec->object, new_object);
-		/*
-		 * @inode will be released by hook_sb_delete() on its
-		 * superblock shutdown.
-		 */
-		ihold(inode);
-		spin_unlock(&inode->i_lock);
-		return new_object;
 	}
+
+	rcu_assign_pointer(inode_sec->object, new_object);
+	/*
+	 * @inode will be released by hook_sb_delete() on its superblock
+	 * shutdown.
+	 */
+	ihold(inode);
+	spin_unlock(&inode->i_lock);
+	return new_object;
 }
 
 /* All access rights which can be tied to files. */
-- 
2.29.2


  parent reply	other threads:[~2020-11-11 21:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-11 21:34 [PATCH v1 0/9] Landlock fixes Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 1/9] landlock: Fix memory allocation error handling Mickaël Salaün
2020-11-11 21:34 ` Mickaël Salaün [this message]
2020-11-20  1:37   ` [PATCH v1 2/9] landlock: Cosmetic fixes for filesystem management James Morris
2020-11-11 21:34 ` [PATCH v1 3/9] landlock: Enforce deterministic interleaved path rules Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 4/9] landlock: Always intersect access rights Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 5/9] landlock: Add extra checks when inserting a rule Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 6/9] selftests/landlock: Extend layout1.inherit_superset Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 7/9] landlock: Clean up get_ruleset_from_fd() Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 8/9] landlock: Add help to enable Landlock as a stacked LSM Mickaël Salaün
2020-11-11 21:34 ` [PATCH v1 9/9] landlock: Extend documentation about limitations Mickaël Salaün
2020-11-12  4:59 ` [PATCH v1 0/9] Landlock fixes James Morris

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