From patchwork Tue Dec 9 22:50:35 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 419318 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 8E517140082 for ; Wed, 10 Dec 2014 09:54:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754483AbaLIWxj (ORCPT ); Tue, 9 Dec 2014 17:53:39 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:37490 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753983AbaLIWum (ORCPT ); Tue, 9 Dec 2014 17:50:42 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1XyTc8-0000bO-SF; Tue, 09 Dec 2014 22:50:40 +0000 From: Al Viro To: David Miller Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 22/25] switch memcpy_to_msg() and skb_copy{, _and_csum}_datagram_msg() to primitives Date: Tue, 9 Dec 2014 22:50:35 +0000 Message-Id: <1418165438-2205-22-git-send-email-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <20141209224928.GL22149@ZenIV.linux.org.uk> References: <20141209224928.GL22149@ZenIV.linux.org.uk> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Al Viro ... making both non-draining. That means that tcp_recvmsg() becomes non-draining. And _that_ would break iscsit_do_rx_data() unless we a) make sure tcp_recvmsg() is uniformly non-draining (it is) b) make sure it copes with arbitrary (including shifted) iov_iter (it does, all it uses is iov_iter primitives) c) make iscsit_do_rx_data() initialize ->msg_iter only once. Fortunately, (c) is doable with minimal work and we are rid of one the two places where kernel send/recvmsg users would be unhappy with non-draining behaviour. Actually, that makes all but one of ->recvmsg() instances iov_iter-clean. The exception is skcipher_recvmsg() and it also isn't hard to convert to primitives (iov_iter_get_pages() is needed there). That'll wait a bit - there's some interplay with ->sendmsg() path for that one. Signed-off-by: Al Viro --- drivers/target/iscsi/iscsi_target_util.c | 12 +++---- include/linux/skbuff.h | 16 +++------- net/core/datagram.c | 54 +++++++++++--------------------- 3 files changed, 28 insertions(+), 54 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index ce87ce9..7c6a95b 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -1326,21 +1326,19 @@ static int iscsit_do_rx_data( struct iscsi_conn *conn, struct iscsi_data_count *count) { - int data = count->data_length, rx_loop = 0, total_rx = 0, iov_len; - struct kvec *iov_p; + int data = count->data_length, rx_loop = 0, total_rx = 0; struct msghdr msg; if (!conn || !conn->sock || !conn->conn_ops) return -1; memset(&msg, 0, sizeof(struct msghdr)); - - iov_p = count->iov; - iov_len = count->iov_count; + iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, + count->iov, count->iov_count, data); while (total_rx < data) { - rx_loop = kernel_recvmsg(conn->sock, &msg, iov_p, iov_len, - (data - total_rx), MSG_WAITALL); + rx_loop = sock_recvmsg(conn->sock, &msg, + (data - total_rx), MSG_WAITALL); if (rx_loop <= 0) { pr_debug("rx_loop: %d total_rx: %d\n", rx_loop, total_rx); diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 52cf1bd..4902f2d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2651,17 +2651,10 @@ int skb_copy_datagram_iter(const struct sk_buff *from, int offset, static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset, struct msghdr *msg, int size) { - /* XXX: stripping const */ - return skb_copy_datagram_iovec(from, offset, (struct iovec *)msg->msg_iter.iov, size); -} -int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen, - struct iovec *iov); -static inline int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen, - struct msghdr *msg) -{ - /* XXX: stripping const */ - return skb_copy_and_csum_datagram_iovec(skb, hlen, (struct iovec *)msg->msg_iter.iov); + return skb_copy_datagram_iter(from, offset, &msg->msg_iter, size); } +int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen, + struct msghdr *msg); int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset, struct iov_iter *from, int len); int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm); @@ -2697,8 +2690,7 @@ static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len) static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len) { - /* XXX: stripping const */ - return memcpy_toiovec((struct iovec *)msg->msg_iter.iov, data, len); + return copy_to_iter(data, len, &msg->msg_iter) == len ? 0 : -EFAULT; } struct skb_checksum_ops { diff --git a/net/core/datagram.c b/net/core/datagram.c index b6e303b..41075ed 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -615,27 +615,25 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from) EXPORT_SYMBOL(zerocopy_sg_from_iter); static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, - u8 __user *to, int len, + struct iov_iter *to, int len, __wsum *csump) { int start = skb_headlen(skb); int i, copy = start - offset; struct sk_buff *frag_iter; int pos = 0; + int n; /* Copy header. */ if (copy > 0) { - int err = 0; if (copy > len) copy = len; - *csump = csum_and_copy_to_user(skb->data + offset, to, copy, - *csump, &err); - if (err) + n = csum_and_copy_to_iter(skb->data + offset, copy, csump, to); + if (n != copy) goto fault; if ((len -= copy) == 0) return 0; offset += copy; - to += copy; pos = copy; } @@ -647,26 +645,22 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, end = start + skb_frag_size(frag); if ((copy = end - offset) > 0) { - __wsum csum2; - int err = 0; - u8 *vaddr; + __wsum csum2 = 0; struct page *page = skb_frag_page(frag); + u8 *vaddr = kmap(page); if (copy > len) copy = len; - vaddr = kmap(page); - csum2 = csum_and_copy_to_user(vaddr + - frag->page_offset + - offset - start, - to, copy, 0, &err); + n = csum_and_copy_to_iter(vaddr + frag->page_offset + + offset - start, copy, + &csum2, to); kunmap(page); - if (err) + if (n != copy) goto fault; *csump = csum_block_add(*csump, csum2, pos); if (!(len -= copy)) return 0; offset += copy; - to += copy; pos += copy; } start = end; @@ -691,7 +685,6 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, if ((len -= copy) == 0) return 0; offset += copy; - to += copy; pos += copy; } start = end; @@ -744,20 +737,19 @@ __sum16 __skb_checksum_complete(struct sk_buff *skb) EXPORT_SYMBOL(__skb_checksum_complete); /** - * skb_copy_and_csum_datagram_iovec - Copy and checksum skb to user iovec. + * skb_copy_and_csum_datagram_msg - Copy and checksum skb to user iovec. * @skb: skbuff * @hlen: hardware length - * @iov: io vector + * @msg: destination * * Caller _must_ check that skb will fit to this iovec. * * Returns: 0 - success. * -EINVAL - checksum failure. - * -EFAULT - fault during copy. Beware, in this case iovec - * can be modified! + * -EFAULT - fault during copy. */ -int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, - int hlen, struct iovec *iov) +int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, + int hlen, struct msghdr *msg) { __wsum csum; int chunk = skb->len - hlen; @@ -765,28 +757,20 @@ int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, if (!chunk) return 0; - /* Skip filled elements. - * Pretty silly, look at memcpy_toiovec, though 8) - */ - while (!iov->iov_len) - iov++; - - if (iov->iov_len < chunk) { + if (iov_iter_count(&msg->msg_iter) < chunk) { if (__skb_checksum_complete(skb)) goto csum_error; - if (skb_copy_datagram_iovec(skb, hlen, iov, chunk)) + if (skb_copy_datagram_msg(skb, hlen, msg, chunk)) goto fault; } else { csum = csum_partial(skb->data, hlen, skb->csum); - if (skb_copy_and_csum_datagram(skb, hlen, iov->iov_base, + if (skb_copy_and_csum_datagram(skb, hlen, &msg->msg_iter, chunk, &csum)) goto fault; if (csum_fold(csum)) goto csum_error; if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) netdev_rx_csum_fault(skb->dev); - iov->iov_len -= chunk; - iov->iov_base += chunk; } return 0; csum_error: @@ -794,7 +778,7 @@ csum_error: fault: return -EFAULT; } -EXPORT_SYMBOL(skb_copy_and_csum_datagram_iovec); +EXPORT_SYMBOL(skb_copy_and_csum_datagram_msg); /** * datagram_poll - generic datagram poll