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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /net/core/user_dma.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
download | FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.gz FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.tar.bz2 FOSSEE-netbook-kernel-source-871480933a1c28f8a9fed4c4d34d06c439a7a422.zip |
Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'net/core/user_dma.c')
-rw-r--r-- | net/core/user_dma.c | 131 |
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 00000000..1b5fefdb --- /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/export.h> +#include <net/tcp.h> +#include <net/netdma.h> + +#define NET_DMA_DEFAULT_COPYBREAK 4096 + +int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK; +EXPORT_SYMBOL(sysctl_tcp_dma_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; + struct sk_buff *frag_iter; + 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; + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + + WARN_ON(start > offset + len); + + end = start + skb_frag_size(frag); + copy = end - offset; + if (copy > 0) { + struct page *page = skb_frag_page(frag); + + 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; + } + + skb_walk_frags(skb, frag_iter) { + int end; + + WARN_ON(start > offset + len); + + end = start + frag_iter->len; + copy = end - offset; + if (copy > 0) { + if (copy > len) + copy = len; + cookie = dma_skb_copy_datagram_iovec(chan, frag_iter, + 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; +} |