From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 525EAC04AA7 for ; Mon, 13 May 2019 13:01:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2745A208C2 for ; Mon, 13 May 2019 13:01:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728459AbfEMNBN (ORCPT ); Mon, 13 May 2019 09:01:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:42088 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727850AbfEMNBN (ORCPT ); Mon, 13 May 2019 09:01:13 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 02C91AF94 for ; Mon, 13 May 2019 13:01:12 +0000 (UTC) Date: Mon, 13 May 2019 15:01:11 +0200 From: Johannes Thumshirn To: dsterba@suse.cz, Linux BTRFS Mailinglist Subject: Re: [PATCH 14/17] btrfs: directly call into crypto framework for checsumming Message-ID: <20190513130111.GD18838@x250.microfocus.com> References: <20190510111547.15310-1-jthumshirn@suse.de> <20190510111547.15310-15-jthumshirn@suse.de> <20190513130003.GD20156@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190513130003.GD20156@suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, May 13, 2019 at 03:00:03PM +0200, David Sterba wrote: > On Fri, May 10, 2019 at 01:15:44PM +0200, Johannes Thumshirn wrote: > > Currently btrfs_csum_data() relied on the crc32c() wrapper around the crypto > > framework for calculating the CRCs. > > > > As we have our own crypto_shash structure in the fs_info now, we can > > directly call into the crypto framework without going trough the wrapper. > > > > Signed-off-by: Johannes Thumshirn > > --- > > fs/btrfs/disk-io.c | 28 ++++++++++++++++++++++++++-- > > 1 file changed, 26 insertions(+), 2 deletions(-) > > > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > > index fb0b06b7b9f6..0c9ac7b45ce8 100644 > > --- a/fs/btrfs/disk-io.c > > +++ b/fs/btrfs/disk-io.c > > @@ -253,12 +253,36 @@ struct extent_map *btree_get_extent(struct btrfs_inode *inode, > > u32 btrfs_csum_data(struct btrfs_fs_info *fs_info, const char *data, > > u32 seed, size_t len) > > { > > - return crc32c(seed, data, len); > > + SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); > > + u32 *ctx = (u32 *)shash_desc_ctx(shash); > > + u32 retval; > > + int err; > > + > > + shash->tfm = fs_info->csum_shash; > > + shash->flags = 0; > > + *ctx = seed; > > + > > + err = crypto_shash_update(shash, data, len); > > + ASSERT(err); > > + > > + retval = *ctx; > > + barrier_data(ctx); > > + > > + return retval; > > I unfortunatelly had a dive into the crypto API calls and since then I'm > biased against using it (too much indirection and extra memory > references). So my idea of this function is: > > switch (fs_info->csum_type) { > case CRC32: > ... calculate crc32c; > break; > case SHA256: > ... calculate sha56; > break; > } > > with direct calls to the hash primitives rather than thravelling trough > the shash. well at least the crc3c2() call we use does nothing else (from lib/libcrc32c.c): u32 crc32c(u32 crc, const void *address, unsigned int length) { SHASH_DESC_ON_STACK(shash, tfm); u32 ret, *ctx = (u32 *)shash_desc_ctx(shash); int err; shash->tfm = tfm; shash->flags = 0; *ctx = crc; err = crypto_shash_update(shash, address, length); BUG_ON(err); ret = *ctx; barrier_data(ctx); return ret; } EXPORT_SYMBOL(crc32c); -- Johannes Thumshirn SUSE Labs Filesystems jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850