From patchwork Sat Dec 21 09:10:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 852794 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BD0631F1934 for ; Sat, 21 Dec 2024 09:11:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734772293; cv=none; b=jNqhYhnqifxkGTwo13onOatdUo5pJgz5jfGmlnzlgx1y6NUJgRt3T80MW0aTtcq+QeTkzmNKXn4amDbowOT4CbeLs9u93gJO0fOXjNwPnWmQN2n1NcybkaOth9HeKmt7LpuifUJgYWVk2sM+wQVgKfldiuftOQftkb6UhtD6xLg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734772293; c=relaxed/simple; bh=Aca6uPsUCVLdX4GRY5oc+9eRqWCqEIgCJje21Fl6qos=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=skA5e8F57JWrjbdnPqbhrUpGr4ftJSOfWz9LtCtDY2olURzlAQzl22V1qefeEfjHuA85uiZb76OL793hCCbw8LxSyCpaESvDfjThl8ecyR87FGBBHCwTfx1kgVzjUrWzZm8/mhEryv0ZbYrP6Z3ybjHg9Llxf89d3nsaIf6iQIk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mPGBks13; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mPGBks13" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40DA2C4CEDE for ; Sat, 21 Dec 2024 09:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734772293; bh=Aca6uPsUCVLdX4GRY5oc+9eRqWCqEIgCJje21Fl6qos=; h=From:To:Subject:Date:In-Reply-To:References:From; b=mPGBks13ksjm0ws9HFGcj6woU1HYnFdK3XNldQVphhUrKV57svAfoQVA/Wvde9uZm coQwk+QcqCEK8fZrInsg7kLTdy7ifd6JaxSzEQ69JdkQvV1uozrS+X+zHAqVa+QxVi FC14jJvkOUGQNtNgs/9vJ1bAAxKhgyitAGDMHUtgAfOobV3cRGfi8onft21REOQ+Rb ncf6qHIg2FyqeGNg2ELEdb02YIYQ3siQDtNcOHIa/T9UMUc8hmju5uE49479fdtmqD 3R4Xoq/XcAKk9Mqd2i4lRDvRFvQlmWFZ6JaEghDKffFUY4VclceAClzVvA6bv2tm6r YxM9wKmmrHk6w== From: Eric Biggers To: linux-crypto@vger.kernel.org Subject: [PATCH 12/29] crypto: scatterwalk - add new functions for skipping data Date: Sat, 21 Dec 2024 01:10:39 -0800 Message-ID: <20241221091056.282098-13-ebiggers@kernel.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241221091056.282098-1-ebiggers@kernel.org> References: <20241221091056.282098-1-ebiggers@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Eric Biggers Add scatterwalk_skip() to skip the given number of bytes in a scatter_walk. Previously support for skipping was provided through scatterwalk_copychunks(..., 2) followed by scatterwalk_done(), which was confusing and less efficient. Also add scatterwalk_start_at_pos() which starts a scatter_walk at the given position, equivalent to scatterwalk_start() + scatterwalk_skip(). This addresses another common need in a more streamlined way. Later patches will convert various users to use these functions. Signed-off-by: Eric Biggers --- crypto/scatterwalk.c | 15 +++++++++++++++ include/crypto/scatterwalk.h | 18 ++++++++++++++++++ 2 files changed, 33 insertions(+) diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 16f6ba896fb6..af436ad02e3f 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -13,10 +13,25 @@ #include #include #include #include +void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes) +{ + struct scatterlist *sg = walk->sg; + + nbytes += walk->offset - sg->offset; + + while (nbytes > sg->length) { + nbytes -= sg->length; + sg = sg_next(sg); + } + walk->sg = sg; + walk->offset = sg->offset + nbytes; +} +EXPORT_SYMBOL_GPL(scatterwalk_skip); + static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out) { void *src = out ? buf : sgdata; void *dst = out ? sgdata : buf; diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h index 924efbaefe67..5c7765f601e0 100644 --- a/include/crypto/scatterwalk.h +++ b/include/crypto/scatterwalk.h @@ -31,10 +31,26 @@ static inline void scatterwalk_start(struct scatter_walk *walk, { walk->sg = sg; walk->offset = sg->offset; } +/* + * This is equivalent to scatterwalk_start(walk, sg) followed by + * scatterwalk_skip(walk, pos). + */ +static inline void scatterwalk_start_at_pos(struct scatter_walk *walk, + struct scatterlist *sg, + unsigned int pos) +{ + while (pos > sg->length) { + pos -= sg->length; + sg = sg_next(sg); + } + walk->sg = sg; + walk->offset = sg->offset + pos; +} + static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk) { unsigned int len = walk->sg->offset + walk->sg->length - walk->offset; unsigned int len_this_page = offset_in_page(~walk->offset) + 1; return len_this_page > len ? len : len_this_page; @@ -90,10 +106,12 @@ static inline void scatterwalk_done(struct scatter_walk *walk, int out, if (!more || walk->offset >= walk->sg->offset + walk->sg->length || !(walk->offset & (PAGE_SIZE - 1))) scatterwalk_pagedone(walk, out, more); } +void scatterwalk_skip(struct scatter_walk *walk, unsigned int nbytes); + void scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out); void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg, unsigned int start, unsigned int nbytes, int out);