From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 315963AD50F; Wed, 29 Jul 2026 05:21:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785302504; cv=none; b=KTeZUEO9FfCnLrEFgniVRWGFGdXix4ypqb8BmhlP2ru0+oirVMNc0AodPh7ZMwh/wwSkUnuklRhhdb93qgMb5l4/03iThOUXVZSoPmazL+TkGPz6zrAHZWV/uKKRj9Ewrbt+Sd9GlYsAoookN7+fTudL3PqOuG/M3l/ofA1EMRA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785302504; c=relaxed/simple; bh=KHltdLZzca2MS+qzleUldbAet8U0oie++G8O+z+ddvA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s2+YaSn4CEQ2fzUCNcB84eVTJ1m2sC+PLKK4msPV5dcFO4lQXruVVzHzcumpN0kTUSxJ02JJlAufvBYhYjuYyi5VjNVJwJ5iJQfyko0EEOf5BwCqmbXckRCNbAbQyyZujzXia8L5NhZpO/DEks4PSv1D8MZnVbmOoLS0XfLc1jk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mUY66haz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mUY66haz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6C391F00A3F; Wed, 29 Jul 2026 05:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785302502; bh=Ugzl1Kpp6sTmEbzkf9pYZyQBabChQKwh3yAmOiKxtF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mUY66hazsrzMBbjvoOzBWyONxl4aqDEV/dwFlJz9Ux93Mb8wFXnxpUvvJcoZWN+gP OWDULYxCmiiAvk55agYMrH8rmClFKK9pNF1AzJl2+62RiCAc94AzLQjrFwOaFhyhHL BsF9ILKJczSOjuetu+FuWWtLMRHZICUghuEtLdcf7TYYaW7aYoMiHqYAOrnLfR8pwY RyY/ViFmbFWLLVq5JRX9i4pYhxHnoo82f+cUkNyca5u2XOrpLI3oocrhOSllym/db5 pfUUl04UOm3Wkj5k7ZE+W75CwlhKWgxa1J1kyDJ3YNSJ0U5CKOF5KcS4XJjJvS3wYY lLg6WVQFzkIBQ== From: Eric Biggers To: stable@vger.kernel.org Cc: dm-devel@lists.linux.dev, Mikulas Patocka , Eric Biggers Subject: [PATCH 6.18 3/4] dm-verity-fec: replace {MAX,MIN}_RSN with {MIN,MAX}_ROOTS Date: Tue, 28 Jul 2026 22:19:08 -0700 Message-ID: <20260729051909.62106-4-ebiggers@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260729051909.62106-1-ebiggers@kernel.org> References: <20260729051909.62106-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit commit 82fbd6a3e29a329d439690cd7ccc4162c9cd8db6 upstream. Every time DM_VERITY_FEC_{MAX,MIN}_RSN are used, they are subtracted from DM_VERITY_FEC_RSM to get the bounds on the number of roots. Therefore, replace these with {MIN,MAX}_ROOTS constants which are more directly useful. (Note the inversion, where MAX_RSN maps to MIN_ROOTS and MIN_RSN maps to MAX_ROOTS.) No functional change. Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka --- drivers/md/dm-verity-fec.c | 6 +++--- drivers/md/dm-verity-fec.h | 7 +++---- 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index a8fbf97b97517..cebcc8fd25d70 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -87,7 +87,7 @@ static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_io *io, int r, corrected = 0, res; struct dm_buffer *buf; unsigned int n, i, j, parity_pos, to_copy; - uint16_t par_buf[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN]; + uint16_t par_buf[DM_VERITY_FEC_MAX_ROOTS]; u8 *par, *block; u64 parity_block; struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size); @@ -605,8 +605,8 @@ int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v, } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) { if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c || - num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) || - num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) { + num_c < DM_VERITY_FEC_MIN_ROOTS || + num_c > DM_VERITY_FEC_MAX_ROOTS) { ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS; return -EINVAL; } diff --git a/drivers/md/dm-verity-fec.h b/drivers/md/dm-verity-fec.h index 90a0af3f35d31..b3460103e0e10 100644 --- a/drivers/md/dm-verity-fec.h +++ b/drivers/md/dm-verity-fec.h @@ -13,8 +13,8 @@ /* Reed-Solomon(M, N) parameters */ #define DM_VERITY_FEC_RSM 255 -#define DM_VERITY_FEC_MAX_RSN 253 -#define DM_VERITY_FEC_MIN_RSN 231 /* ~10% space overhead */ +#define DM_VERITY_FEC_MIN_ROOTS 2 /* RS(255, 253): ~0.8% space overhead */ +#define DM_VERITY_FEC_MAX_ROOTS 24 /* RS(255, 231): ~10% space overhead */ /* buffers for deinterleaving and decoding */ #define DM_VERITY_FEC_BUF_PREALLOC 1 /* buffers to preallocate */ @@ -50,8 +50,7 @@ struct dm_verity_fec { /* per-bio data */ struct dm_verity_fec_io { struct rs_control *rs; /* Reed-Solomon state */ - /* erasures for decode_rs8 */ - int erasures[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN + 1]; + int erasures[DM_VERITY_FEC_MAX_ROOTS + 1]; /* erasures for decode_rs8 */ u8 *bufs[DM_VERITY_FEC_BUF_MAX]; /* bufs for deinterleaving */ unsigned int nbufs; /* number of buffers allocated */ u8 *output; /* buffer for corrected output */ -- 2.55.0