Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 26 Jun 2019 06:04:09 -0700
From:   tip-bot for Ferdinand Blomqvist <tipbot@zytor.com>
Message-ID: <tip-ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9@git.kernel.org>
Cc:     tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com,
        ferdinand.blomqvist@gmail.com, mingo@kernel.org
Reply-To: mingo@kernel.org, linux-kernel@vger.kernel.org,
          ferdinand.blomqvist@gmail.com, hpa@zytor.com, tglx@linutronix.de
In-Reply-To: <20190620141039.9874-6-ferdinand.blomqvist@gmail.com>
References: <20190620141039.9874-6-ferdinand.blomqvist@gmail.com>
To:     linux-tip-commits@vger.kernel.org
Subject: [tip:core/rslib] rslib: Fix handling of of caller provided syndrome
Git-Commit-ID: ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9
Robot-ID: <tip-bot.git.kernel.org>
Robot-Unsubscribe: Contact <mailto:hpa@kernel.org> to get blacklisted from
 these emails
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=UTF-8
Content-Disposition: inline
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Commit-ID:  ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9
Gitweb:     https://git.kernel.org/tip/ef4d6a8556b637ad27c8c2a2cff1dda3da38e9a9
Author:     Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
AuthorDate: Thu, 20 Jun 2019 17:10:37 +0300
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 26 Jun 2019 14:55:47 +0200

rslib: Fix handling of of caller provided syndrome

Check if the syndrome provided by the caller is zero, and act
accordingly.

Signed-off-by: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190620141039.9874-6-ferdinand.blomqvist@gmail.com

---
 lib/reed_solomon/decode_rs.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c
index 78629bbe6590..b7264a712d46 100644
--- a/lib/reed_solomon/decode_rs.c
+++ b/lib/reed_solomon/decode_rs.c
@@ -42,8 +42,18 @@
 	BUG_ON(pad < 0 || pad >= nn - nroots);
 
 	/* Does the caller provide the syndrome ? */
-	if (s != NULL)
-		goto decode;
+	if (s != NULL) {
+		for (i = 0; i < nroots; i++) {
+			/* The syndrome is in index form,
+			 * so nn represents zero
+			 */
+			if (s[i] != nn)
+				goto decode;
+		}
+
+		/* syndrome is zero, no errors to correct  */
+		return 0;
+	}
 
 	/* form the syndromes; i.e., evaluate data(x) at roots of
 	 * g(x) */