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authorLinus Torvalds <torvalds@g5.osdl.org>2006-06-19 18:55:56 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-19 18:55:56 -0700
commitd0b952a9837f81cd89e756b1b34293fa6e1cb59d (patch)
treefbe488bc5f407afa0e91cefb262d9e9ee69062ac /net/core/user_dma.c
parentd90125bfe958ed0451c6b98f831c86aba08b43d5 (diff)
parent47552c4e555eefe381f3d45140b59a2ea4b16486 (diff)
Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: (109 commits) [ETHTOOL]: Fix UFO typo [SCTP]: Fix persistent slowdown in sctp when a gap ack consumes rx buffer. [SCTP]: Send only 1 window update SACK per message. [SCTP]: Don't do CRC32C checksum over loopback. [SCTP] Reset rtt_in_progress for the chunk when processing its sack. [SCTP]: Reject sctp packets with broadcast addresses. [SCTP]: Limit association max_retrans setting in setsockopt. [PFKEYV2]: Fix inconsistent typing in struct sadb_x_kmprivate. [IPV6]: Sum real space for RTAs. [IRDA]: Use put_unaligned() in irlmp_do_discovery(). [BRIDGE]: Add support for NETIF_F_HW_CSUM devices [NET]: Add NETIF_F_GEN_CSUM and NETIF_F_ALL_CSUM [TG3]: Convert to non-LLTX [TG3]: Remove unnecessary tx_lock [TCP]: Add tcp_slow_start_after_idle sysctl. [BNX2]: Update version and reldate [BNX2]: Use CPU native page size [BNX2]: Use compressed firmware [BNX2]: Add firmware decompression [BNX2]: Allow WoL settings on new 5708 chips ... Manual fixup for conflict in drivers/net/tulip/winbond-840.c
Diffstat (limited to 'net/core/user_dma.c')
-rw-r--r--net/core/user_dma.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/net/core/user_dma.c b/net/core/user_dma.c
new file mode 100644
index 000000000000..b7c98dbcdb81
--- /dev/null
+++ b/net/core/user_dma.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
+ * Portions based on net/core/datagram.c and copyrighted by their authors.
+ *
+ * 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., 59
+ * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+
+/*
+ * This code allows the net stack to make use of a DMA engine for
+ * skb to iovec copies.
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/socket.h>
+#include <linux/rtnetlink.h> /* for BUG_TRAP */
+#include <net/tcp.h>
+
+#define NET_DMA_DEFAULT_COPYBREAK 4096
+
+int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
+
+/**
+ * dma_skb_copy_datagram_iovec - Copy a datagram to an iovec.
+ * @skb - buffer to copy
+ * @offset - offset in the buffer to start copying from
+ * @iovec - io vector to copy to
+ * @len - amount of data to copy from buffer to iovec
+ * @pinned_list - locked iovec buffer data
+ *
+ * Note: the iovec is modified during the copy.
+ */
+int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
+ struct sk_buff *skb, int offset, struct iovec *to,
+ size_t len, struct dma_pinned_list *pinned_list)
+{
+ int start = skb_headlen(skb);
+ int i, copy = start - offset;
+ dma_cookie_t cookie = 0;
+
+ /* Copy header. */
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ cookie = dma_memcpy_to_iovec(chan, to, pinned_list,
+ skb->data + offset, copy);
+ if (cookie < 0)
+ goto fault;
+ len -= copy;
+ if (len == 0)
+ goto end;
+ offset += copy;
+ }
+
+ /* Copy paged appendix. Hmm... why does this look so complicated? */
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + skb_shinfo(skb)->frags[i].size;
+ copy = end - offset;
+ if ((copy = end - offset) > 0) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ struct page *page = frag->page;
+
+ if (copy > len)
+ copy = len;
+
+ cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page,
+ frag->page_offset + offset - start, copy);
+ if (cookie < 0)
+ goto fault;
+ len -= copy;
+ if (len == 0)
+ goto end;
+ offset += copy;
+ }
+ start = end;
+ }
+
+ if (skb_shinfo(skb)->frag_list) {
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ for (; list; list = list->next) {
+ int end;
+
+ BUG_TRAP(start <= offset + len);
+
+ end = start + list->len;
+ copy = end - offset;
+ if (copy > 0) {
+ if (copy > len)
+ copy = len;
+ cookie = dma_skb_copy_datagram_iovec(chan, list,
+ offset - start, to, copy,
+ pinned_list);
+ if (cookie < 0)
+ goto fault;
+ len -= copy;
+ if (len == 0)
+ goto end;
+ offset += copy;
+ }
+ start = end;
+ }
+ }
+
+end:
+ if (!len) {
+ skb->dma_cookie = cookie;
+ return cookie;
+ }
+
+fault:
+ return -EFAULT;
+}