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From:   Eric Biggers <ebiggers3@gmail.com>
To:     David Howells <dhowells@redhat.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, Eric Biggers <ebiggers@google.com>
Subject: [PATCH 16/18] fs_context: de-obfuscate control flow in fscontext_read()
Date:   Sun,  8 Jul 2018 14:01:52 -0700
Message-Id: <20180708210154.10423-17-ebiggers3@gmail.com>
In-Reply-To: <20180708210154.10423-1-ebiggers3@gmail.com>
References: <20180708210154.10423-1-ebiggers3@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Eric Biggers <ebiggers@google.com>

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/fsopen.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/fsopen.c b/fs/fsopen.c
index 1fbd8b0ca194b..dd38f6b65aace 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -161,20 +161,18 @@ static ssize_t fscontext_read(struct file *file,
 	if (ret < 0)
 		return ret;
 
-	ret = -ENODATA;
-	if (log->head != log->tail) {
-		index = log->tail & (logsize - 1);
-		p = log->buffer[index];
-		need_free = log->need_free & (1 << index);
-		log->buffer[index] = NULL;
-		log->need_free &= ~(1 << index);
-		log->tail++;
-		ret = 0;
+	if (log->head == log->tail) {
+		mutex_unlock(&fc->uapi_mutex);
+		return -ENODATA;
 	}
 
+	index = log->tail & (logsize - 1);
+	p = log->buffer[index];
+	need_free = log->need_free & (1 << index);
+	log->buffer[index] = NULL;
+	log->need_free &= ~(1 << index);
+	log->tail++;
 	mutex_unlock(&fc->uapi_mutex);
-	if (ret < 0)
-		return ret;
 
 	ret = -EMSGSIZE;
 	n = strlen(p);
-- 
2.18.0