From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) (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 39C2C39E6F9 for ; Wed, 14 Jan 2026 15:41:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.145.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768405292; cv=none; b=AEuNVNSMchoOEcfOr7j5Up3V6k1D1D/Pa+MCQ9dCMuzzUG7KjXxIMldw/OvSqCHDPo5wEM7DYAl8q3yNkVJjrkr/6tBwDzSVvAmKCH0CIPSPyLyASJbY3HW7s4I6cVw3g+xhjMyDJed07/NEp7SCMyGHiUDLAJSeCxio5qplp44= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768405292; c=relaxed/simple; bh=qIouyY3fKmuViCEeKZxTjLce/wKwht8J40XAeImObcA=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=L814TQiFUavYhe2TuwvqMJ922C9mAVX0VseNlbBGhhq0oHL81mxilS4M5+m9Hfmeix6aRytRkNks0uUN+Xew7bhtkzrrhDV6rZjkcvVB59tSwc4uv9lvHXuDxjp+mmF2vn0CAti10wrQutHCPPw363KBSrz0iFPCCsxQVEmortU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com; spf=pass smtp.mailfrom=meta.com; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b=K+hTlyFc; arc=none smtp.client-ip=67.231.145.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=meta.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=meta.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=meta.com header.i=@meta.com header.b="K+hTlyFc" Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 60EETA012381882 for ; Wed, 14 Jan 2026 07:41:26 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=s2048-2025-q2; bh=e3O4DzHwT2aUh+ZzPv0ZOqRBYBNwIQBl0Mi1HJ6BUMI=; b=K+hTlyFc3oxG rN6Jl9sqCEzdt3NOLDyw3Y1LvANJNQHIgAOeA0OVvehcAr+BCL+vV9nRBZiCA69Q mKsp/9wJq2hzPtbpy0lc5/UdrUhMKecBlnEArT6i8pU3pCQS31wvahepr69yb/7A nM2O/j9NCFx2Yf7Jq3HWBFP+5GR1Sk0grhsb1tqGtZF54kvVxlzSHqqan3eTD4OK ce3VRAo0sfmZC/U5hsCGaa8uwKmc54zmVTkCxu4d8plRg+1fMlHW+cXkWYnkrn5i dZ/LEK2MYRyKSVCm244MEG9ye8zyH+n8IKGT5iEZ6TdQWV0+lBlxsScfMsP7NL6m DDESTL/WIQ== Received: from maileast.thefacebook.com ([163.114.135.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 4bp0fywqf2-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 14 Jan 2026 07:41:26 -0800 (PST) Received: from twshared17475.04.snb3.facebook.com (2620:10d:c0a8:1b::8e35) by mail.thefacebook.com (2620:10d:c0a9:6f::8fd4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.29; Wed, 14 Jan 2026 15:41:23 +0000 Received: by devbig197.nha3.facebook.com (Postfix, from userid 544533) id 0371163A8FFA; Wed, 14 Jan 2026 07:41:13 -0800 (PST) From: Keith Busch To: , , , , , CC: Keith Busch Subject: [PATCHv2 2/3] dm-crypt: allow unaligned bio_vecs for direct io Date: Wed, 14 Jan 2026 07:41:12 -0800 Message-ID: <20260114154113.3207790-3-kbusch@meta.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260114154113.3207790-1-kbusch@meta.com> References: <20260114154113.3207790-1-kbusch@meta.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-ORIG-GUID: ok7kjcmQGfMJrnrx7MwvijrcZ0CMfQsr X-Authority-Analysis: v=2.4 cv=QKplhwLL c=1 sm=1 tr=0 ts=6967b926 cx=c_pps a=MfjaFnPeirRr97d5FC5oHw==:117 a=MfjaFnPeirRr97d5FC5oHw==:17 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=_h08JpkXp4QKfwmzJH8A:9 X-Proofpoint-GUID: ok7kjcmQGfMJrnrx7MwvijrcZ0CMfQsr X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTE0MDEzMSBTYWx0ZWRfX9sF8t8JK/Itp xY1FSZhdoc2IET6gS0Bj6GSlEInaBwcvrRuYJ2jha0BTX0oYMOciBS3gLFfIFJy6jWADX0uSyxb yBwKt0oXgo7dPKxJhGp9p5cdc9/F0lqzK6Vs4IEU8mCECh3g5WDccy0O+rmEqiECmkjoNEt1gnn 4tSiVFlD/A0gmhzpGRRNLbyyey8qV6IJXgkCiwmDOwcdKSupq7WkCX1wgI2N7W0zMa7PutyXH5O gzkVU5I6Esg8BhYDkivMjxUFCOurQ9L4wkZzYdPq5Mc6hWEu3MwBBfs4eDZtoA66RPPIN6pV0zO FJcxTiVBCAdBi7olZxy+3Eefjur5emXIqDi5Q8xGEhBwe0W4KTkTP4/pOwET4ohYbQUSJFOyETC eolQ/r1FAD/9xX7/ktesrqj9fajilRGzghlTZDHdsigwINulmB8BQ/NgniGXXQlyTxJlpeMfWbD CO1zDseY2dXePOPpW6A== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2026-01-14_04,2026-01-14_01,2025-10-01_01 From: Keith Busch Many storage devices can handle DMA for data that is not aligned to the sector block size. The block and filesystem layers have introduced updates to allow that kind of memory alignment flexibility when possible. dm-crypt, however, currently constrains itself to aligned memory because it sends a single scatterlist element for the input ot the encrypt and decrypt algorithms. This forces applications that have unaligned data to copy through a bounce buffer, increasing CPU and memory utilization. Use multiple scatterlist elements to relax the memory alignment requirement. To keep this simple, this lower constraint is enabled only for certain encryption and initialization vector types, specifically the ones that don't had additional use for the request base scatterlist elements beyond holding decrypted data. Signed-off-by: Keith Busch --- drivers/md/dm-crypt.c | 73 ++++++++++++++++++++++++++++++++----------- 1 file changed, 55 insertions(+), 18 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 5ef43231fe77f..0b3f5411695ac 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -214,6 +214,7 @@ struct crypt_config { unsigned int key_extra_size; /* additional keys length */ unsigned int key_mac_size; /* MAC key size for authenc(...) */ =20 + unsigned int dio_alignment; unsigned int integrity_tag_size; unsigned int integrity_iv_size; unsigned int used_tag_size; @@ -1424,22 +1425,49 @@ static int crypt_convert_block_aead(struct crypt_= config *cc, return r; } =20 +static int crypt_build_sgl(struct crypt_config *cc, struct scatterlist *= sg, + struct bvec_iter *iter, struct bio *bio, + int max_segs) +{ + unsigned int bytes =3D cc->sector_size; + struct bvec_iter tmp =3D *iter; + int segs, i =3D 0; + + bio_advance_iter(bio, &tmp, bytes); + segs =3D tmp.bi_idx - iter->bi_idx + !!tmp.bi_bvec_done; + if (segs > max_segs) + return -EIO; + + sg_init_table(sg, segs); + do { + struct bio_vec bv =3D mp_bvec_iter_bvec(bio->bi_io_vec, *iter); + int len =3D min(bytes, bv.bv_len); + + /* Reject unexpected unaligned bio. */ + if (unlikely((len | bv.bv_offset) & + bdev_dma_alignment(cc->dev->bdev))) + return -EIO; + + sg_set_page(&sg[i++], bv.bv_page, len, bv.bv_offset); + bio_advance_iter_single(bio, iter, len); + bytes -=3D len; + } while (bytes); + + if (WARN_ON_ONCE(i !=3D segs)) + return -EINVAL; + return 0; +} + static int crypt_convert_block_skcipher(struct crypt_config *cc, struct convert_context *ctx, struct skcipher_request *req, unsigned int tag_offset) { - struct bio_vec bv_in =3D bio_iter_iovec(ctx->bio_in, ctx->iter_in); - struct bio_vec bv_out =3D bio_iter_iovec(ctx->bio_out, ctx->iter_out); struct scatterlist *sg_in, *sg_out; struct dm_crypt_request *dmreq; u8 *iv, *org_iv, *tag_iv; __le64 *sector; - int r =3D 0; - - /* Reject unexpected unaligned bio. */ - if (unlikely(bv_in.bv_len & (cc->sector_size - 1))) - return -EIO; + int r; =20 dmreq =3D dmreq_of_req(cc, req); dmreq->iv_sector =3D ctx->cc_sector; @@ -1456,15 +1484,18 @@ static int crypt_convert_block_skcipher(struct cr= ypt_config *cc, sector =3D org_sector_of_dmreq(cc, dmreq); *sector =3D cpu_to_le64(ctx->cc_sector - cc->iv_offset); =20 - /* For skcipher we use only the first sg item */ sg_in =3D &dmreq->sg_in[0]; sg_out =3D &dmreq->sg_out[0]; =20 - sg_init_table(sg_in, 1); - sg_set_page(sg_in, bv_in.bv_page, cc->sector_size, bv_in.bv_offset); + r =3D crypt_build_sgl(cc, sg_in, &ctx->iter_in, ctx->bio_in, + ARRAY_SIZE(dmreq->sg_in)); + if (r < 0) + return r; =20 - sg_init_table(sg_out, 1); - sg_set_page(sg_out, bv_out.bv_page, cc->sector_size, bv_out.bv_offset); + r =3D crypt_build_sgl(cc, sg_out, &ctx->iter_out, ctx->bio_out, + ARRAY_SIZE(dmreq->sg_out)); + if (r < 0) + return r; =20 if (cc->iv_gen_ops) { /* For READs use IV stored in integrity metadata */ @@ -1495,9 +1526,6 @@ static int crypt_convert_block_skcipher(struct cryp= t_config *cc, if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post) r =3D cc->iv_gen_ops->post(cc, org_iv, dmreq); =20 - bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size); - bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size); - return r; } =20 @@ -2829,10 +2857,12 @@ static void crypt_dtr(struct dm_target *ti) static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode) { struct crypt_config *cc =3D ti->private; + bool unaligned_allowed =3D true; =20 - if (crypt_integrity_aead(cc)) + if (crypt_integrity_aead(cc)) { cc->iv_size =3D crypto_aead_ivsize(any_tfm_aead(cc)); - else + unaligned_allowed =3D false; + } else cc->iv_size =3D crypto_skcipher_ivsize(any_tfm(cc)); =20 if (cc->iv_size) @@ -2868,6 +2898,7 @@ static int crypt_ctr_ivmode(struct dm_target *ti, c= onst char *ivmode) if (cc->key_extra_size > ELEPHANT_MAX_KEY_SIZE) return -EINVAL; set_bit(CRYPT_ENCRYPT_PREPROCESS, &cc->cipher_flags); + unaligned_allowed =3D false; } else if (strcmp(ivmode, "lmk") =3D=3D 0) { cc->iv_gen_ops =3D &crypt_iv_lmk_ops; /* @@ -2880,10 +2911,12 @@ static int crypt_ctr_ivmode(struct dm_target *ti,= const char *ivmode) cc->key_parts++; cc->key_extra_size =3D cc->key_size / cc->key_parts; } + unaligned_allowed =3D false; } else if (strcmp(ivmode, "tcw") =3D=3D 0) { cc->iv_gen_ops =3D &crypt_iv_tcw_ops; cc->key_parts +=3D 2; /* IV + whitening */ cc->key_extra_size =3D cc->iv_size + TCW_WHITENING_SIZE; + unaligned_allowed =3D false; } else if (strcmp(ivmode, "random") =3D=3D 0) { cc->iv_gen_ops =3D &crypt_iv_random_ops; /* Need storage space in integrity fields. */ @@ -2893,6 +2926,8 @@ static int crypt_ctr_ivmode(struct dm_target *ti, c= onst char *ivmode) return -EINVAL; } =20 + if (unaligned_allowed) + cc->dio_alignment =3D 3; return 0; } =20 @@ -3286,6 +3321,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned= int argc, char **argv) cc->key_size =3D key_size; cc->sector_size =3D (1 << SECTOR_SHIFT); cc->sector_shift =3D 0; + cc->dio_alignment =3D 0; =20 ti->private =3D cc; =20 @@ -3750,7 +3786,8 @@ static void crypt_io_hints(struct dm_target *ti, st= ruct queue_limits *limits) limits->physical_block_size =3D max_t(unsigned int, limits->physical_block_size, cc->sector_size); limits->io_min =3D max_t(unsigned int, limits->io_min, cc->sector_size)= ; - limits->dma_alignment =3D limits->logical_block_size - 1; + limits->dma_alignment =3D min_not_zero(limits->logical_block_size - 1, + cc->dio_alignment); =20 /* * For zoned dm-crypt targets, there will be no internal splitting of --=20 2.47.3