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From: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Subject: [RFC PATCH 2/7] rslib: Fix decoding of shortened codes
Date: Sat, 30 Mar 2019 20:29:42 +0200	[thread overview]
Message-ID: <20190330182947.8823-3-ferdinand.blomqvist@gmail.com> (raw)
In-Reply-To: <20190330182947.8823-1-ferdinand.blomqvist@gmail.com>

The decoder is broken. It only works with full length codes.

Signed-off-by: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
---
 lib/reed_solomon/decode_rs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c
index 1db74eb098d0..3313bf944ff1 100644
--- a/lib/reed_solomon/decode_rs.c
+++ b/lib/reed_solomon/decode_rs.c
@@ -99,9 +99,9 @@
 	if (no_eras > 0) {
 		/* Init lambda to be the erasure locator polynomial */
 		lambda[1] = alpha_to[rs_modnn(rs,
-					      prim * (nn - 1 - eras_pos[0]))];
+					prim * (nn - 1 - (eras_pos[0] + pad)))];
 		for (i = 1; i < no_eras; i++) {
-			u = rs_modnn(rs, prim * (nn - 1 - eras_pos[i]));
+			u = rs_modnn(rs, prim * (nn - 1 - (eras_pos[i] + pad)));
 			for (j = i + 1; j > 0; j--) {
 				tmp = index_of[lambda[j - 1]];
 				if (tmp != nn) {
-- 
2.17.2


  parent reply	other threads:[~2019-03-30 18:30 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-30 18:29 [RFC PATCH 0/7] rslib: RS decoder is severely broken Ferdinand Blomqvist
2019-03-30 18:29 ` [RFC PATCH 1/7] rslib: Add tests for the encoder and decoder Ferdinand Blomqvist
2019-06-17 20:44   ` Thomas Gleixner
2019-03-30 18:29 ` Ferdinand Blomqvist [this message]
2019-06-17 20:46   ` [RFC PATCH 2/7] rslib: Fix decoding of shortened codes Thomas Gleixner
2019-03-30 18:29 ` [RFC PATCH 3/7] rslib: decode_rs: Fix length parameter check Ferdinand Blomqvist
2019-06-17 20:46   ` Thomas Gleixner
2019-03-30 18:29 ` [RFC PATCH 4/7] rslib: decode_rs: code cleanup Ferdinand Blomqvist
2019-06-17 20:47   ` Thomas Gleixner
2019-03-30 18:29 ` [RFC PATCH 5/7] rslib: Fix handling of of caller provided syndrome Ferdinand Blomqvist
2019-06-17 20:49   ` Thomas Gleixner
2019-03-30 18:29 ` [RFC PATCH 6/7] rslib: Update documentation Ferdinand Blomqvist
2019-06-17 20:49   ` Thomas Gleixner
2019-03-30 18:29 ` [RFC PATCH 7/7] rslib: Fix remaining decoder flaws Ferdinand Blomqvist
2019-06-17 21:00   ` Thomas Gleixner
2019-06-20 12:09     ` Ferdinand Blomqvist
2019-04-04 11:24 ` [RFC PATCH 0/7] rslib: RS decoder is severely broken Thomas Gleixner
2019-05-09 15:09   ` Ferdinand Blomqvist
2019-05-24  7:25     ` Thomas Gleixner

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