From: =?UTF-8?q?Miloslav=20Trma=C4=8D?= Subject: [PATCH 16/19] Add helpers for zero-copy userspace access Date: Fri, 20 Aug 2010 10:46:00 +0200 Message-ID: <1282293963-27807-18-git-send-email-mitr@redhat.com> References: <1282293963-27807-1-git-send-email-mitr@redhat.com> Cc: linux-crypto@vger.kernel.org, Nikos Mavrogiannopoulos , Neil Horman , linux-kernel@vger.kernel.org, =?UTF-8?q?Miloslav=20Trma=C4=8D?= To: Herbert Xu Return-path: In-Reply-To: <1282293963-27807-1-git-send-email-mitr@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org --- crypto/userspace/cryptodev_main.c | 87 +++++++++++++++++++++++++++++++++++++ 1 files changed, 87 insertions(+), 0 deletions(-) diff --git a/crypto/userspace/cryptodev_main.c b/crypto/userspace/cryptodev_main.c index c6419f4..a6712db 100644 --- a/crypto/userspace/cryptodev_main.c +++ b/crypto/userspace/cryptodev_main.c @@ -1,3 +1,46 @@ +/* + * Driver for /dev/crypto device (aka CryptoDev) + * + * Copyright (c) 2004 Michal Ludvig , SuSE Labs + * Copyright (c) 2009,2010 Nikos Mavrogiannopoulos + * + * This file is part of linux cryptodev. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +/* + * Device /dev/crypto provides an interface for + * accessing kernel CryptoAPI algorithms (ciphers, + * hashes) from userspace programs. + * + * /dev/crypto interface was originally introduced in + * OpenBSD and this module attempts to keep the API. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include #include "cryptodev_int.h" #include "ncr-int.h" #include @@ -11,3 +54,47 @@ MODULE_LICENSE("GPL"); int cryptodev_verbosity = 0; module_param(cryptodev_verbosity, int, 0644); MODULE_PARM_DESC(cryptodev_verbosity, "0: normal, 1: verbose, 2: debug"); + +/* ====== CryptoAPI ====== */ + +void release_user_pages(struct page **pg, int pagecount) +{ + while (pagecount--) { + if (!PageReserved(pg[pagecount])) + SetPageDirty(pg[pagecount]); + page_cache_release(pg[pagecount]); + } +} + +/* offset of buf in it's first page */ +#define PAGEOFFSET(buf) ((unsigned long)buf & ~PAGE_MASK) + +/* fetch the pages addr resides in into pg and initialise sg with them */ +int __get_userbuf(uint8_t __user *addr, uint32_t len, int write, + int pgcount, struct page **pg, struct scatterlist *sg) +{ + int ret, pglen, i = 0; + struct scatterlist *sgp; + + down_write(¤t->mm->mmap_sem); + ret = get_user_pages(current, current->mm, + (unsigned long)addr, pgcount, write, 0, pg, NULL); + up_write(¤t->mm->mmap_sem); + if (ret != pgcount) + return -EINVAL; + + sg_init_table(sg, pgcount); + + pglen = min((ptrdiff_t)(PAGE_SIZE - PAGEOFFSET(addr)), (ptrdiff_t)len); + sg_set_page(sg, pg[i++], pglen, PAGEOFFSET(addr)); + + len -= pglen; + for (sgp = sg_next(sg); len; sgp = sg_next(sgp)) { + pglen = min((uint32_t)PAGE_SIZE, len); + sg_set_page(sgp, pg[i++], pglen, 0); + len -= pglen; + } + sg_mark_end(sg_last(sg, pgcount)); + return 0; +} + -- 1.7.2.1