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28#include <linux/dmaengine.h>
29#include <linux/socket.h>
30#include <net/tcp.h>
31#include <net/netdma.h>
32
33#define NET_DMA_DEFAULT_COPYBREAK 4096
34
35int sysctl_tcp_dma_copybreak = NET_DMA_DEFAULT_COPYBREAK;
36EXPORT_SYMBOL(sysctl_tcp_dma_copybreak);
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47
48int dma_skb_copy_datagram_iovec(struct dma_chan *chan,
49 struct sk_buff *skb, int offset, struct iovec *to,
50 size_t len, struct dma_pinned_list *pinned_list)
51{
52 int start = skb_headlen(skb);
53 int i, copy = start - offset;
54 struct sk_buff *frag_iter;
55 dma_cookie_t cookie = 0;
56
57
58 if (copy > 0) {
59 if (copy > len)
60 copy = len;
61 cookie = dma_memcpy_to_iovec(chan, to, pinned_list,
62 skb->data + offset, copy);
63 if (cookie < 0)
64 goto fault;
65 len -= copy;
66 if (len == 0)
67 goto end;
68 offset += copy;
69 }
70
71
72 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
73 int end;
74
75 WARN_ON(start > offset + len);
76
77 end = start + skb_shinfo(skb)->frags[i].size;
78 copy = end - offset;
79 if (copy > 0) {
80 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
81 struct page *page = frag->page;
82
83 if (copy > len)
84 copy = len;
85
86 cookie = dma_memcpy_pg_to_iovec(chan, to, pinned_list, page,
87 frag->page_offset + offset - start, copy);
88 if (cookie < 0)
89 goto fault;
90 len -= copy;
91 if (len == 0)
92 goto end;
93 offset += copy;
94 }
95 start = end;
96 }
97
98 skb_walk_frags(skb, frag_iter) {
99 int end;
100
101 WARN_ON(start > offset + len);
102
103 end = start + frag_iter->len;
104 copy = end - offset;
105 if (copy > 0) {
106 if (copy > len)
107 copy = len;
108 cookie = dma_skb_copy_datagram_iovec(chan, frag_iter,
109 offset - start,
110 to, copy,
111 pinned_list);
112 if (cookie < 0)
113 goto fault;
114 len -= copy;
115 if (len == 0)
116 goto end;
117 offset += copy;
118 }
119 start = end;
120 }
121
122end:
123 if (!len) {
124 skb->dma_cookie = cookie;
125 return cookie;
126 }
127
128fault:
129 return -EFAULT;
130}
131