Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / sunrpc / socklib.c
bloba661a3acb37e682dba442b98ec1c9729a75f7f5f
1 /*
2 * linux/net/sunrpc/socklib.c
4 * Common socket helper routines for RPC client and server
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
9 #include <linux/compiler.h>
10 #include <linux/netdevice.h>
11 #include <linux/skbuff.h>
12 #include <linux/types.h>
13 #include <linux/pagemap.h>
14 #include <linux/udp.h>
15 #include <linux/sunrpc/xdr.h>
18 /**
19 * xdr_skb_read_bits - copy some data bits from skb to internal buffer
20 * @desc: sk_buff copy helper
21 * @to: copy destination
22 * @len: number of bytes to copy
24 * Possibly called several times to iterate over an sk_buff and copy
25 * data out of it.
27 size_t xdr_skb_read_bits(struct xdr_skb_reader *desc, void *to, size_t len)
29 if (len > desc->count)
30 len = desc->count;
31 if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
32 return 0;
33 desc->count -= len;
34 desc->offset += len;
35 return len;
37 EXPORT_SYMBOL_GPL(xdr_skb_read_bits);
39 /**
40 * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
41 * @desc: sk_buff copy helper
42 * @to: copy destination
43 * @len: number of bytes to copy
45 * Same as skb_read_bits, but calculate a checksum at the same time.
47 static size_t xdr_skb_read_and_csum_bits(struct xdr_skb_reader *desc, void *to, size_t len)
49 unsigned int pos;
50 __wsum csum2;
52 if (len > desc->count)
53 len = desc->count;
54 pos = desc->offset;
55 csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
56 desc->csum = csum_block_add(desc->csum, csum2, pos);
57 desc->count -= len;
58 desc->offset += len;
59 return len;
62 /**
63 * xdr_partial_copy_from_skb - copy data out of an skb
64 * @xdr: target XDR buffer
65 * @base: starting offset
66 * @desc: sk_buff copy helper
67 * @copy_actor: virtual method for copying data
70 ssize_t xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base, struct xdr_skb_reader *desc, xdr_skb_read_actor copy_actor)
72 struct page **ppage = xdr->pages;
73 unsigned int len, pglen = xdr->page_len;
74 ssize_t copied = 0;
75 size_t ret;
77 len = xdr->head[0].iov_len;
78 if (base < len) {
79 len -= base;
80 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
81 copied += ret;
82 if (ret != len || !desc->count)
83 goto out;
84 base = 0;
85 } else
86 base -= len;
88 if (unlikely(pglen == 0))
89 goto copy_tail;
90 if (unlikely(base >= pglen)) {
91 base -= pglen;
92 goto copy_tail;
94 if (base || xdr->page_base) {
95 pglen -= base;
96 base += xdr->page_base;
97 ppage += base >> PAGE_CACHE_SHIFT;
98 base &= ~PAGE_CACHE_MASK;
100 do {
101 char *kaddr;
103 /* ACL likes to be lazy in allocating pages - ACLs
104 * are small by default but can get huge. */
105 if (unlikely(*ppage == NULL)) {
106 *ppage = alloc_page(GFP_ATOMIC);
107 if (unlikely(*ppage == NULL)) {
108 if (copied == 0)
109 copied = -ENOMEM;
110 goto out;
114 len = PAGE_CACHE_SIZE;
115 kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
116 if (base) {
117 len -= base;
118 if (pglen < len)
119 len = pglen;
120 ret = copy_actor(desc, kaddr + base, len);
121 base = 0;
122 } else {
123 if (pglen < len)
124 len = pglen;
125 ret = copy_actor(desc, kaddr, len);
127 flush_dcache_page(*ppage);
128 kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
129 copied += ret;
130 if (ret != len || !desc->count)
131 goto out;
132 ppage++;
133 } while ((pglen -= len) != 0);
134 copy_tail:
135 len = xdr->tail[0].iov_len;
136 if (base < len)
137 copied += copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
138 out:
139 return copied;
141 EXPORT_SYMBOL_GPL(xdr_partial_copy_from_skb);
144 * csum_partial_copy_to_xdr - checksum and copy data
145 * @xdr: target XDR buffer
146 * @skb: source skb
148 * We have set things up such that we perform the checksum of the UDP
149 * packet in parallel with the copies into the RPC client iovec. -DaveM
151 int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
153 struct xdr_skb_reader desc;
155 desc.skb = skb;
156 desc.offset = sizeof(struct udphdr);
157 desc.count = skb->len - desc.offset;
159 if (skb_csum_unnecessary(skb))
160 goto no_checksum;
162 desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
163 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
164 return -1;
165 if (desc.offset != skb->len) {
166 __wsum csum2;
167 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
168 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
170 if (desc.count)
171 return -1;
172 if (csum_fold(desc.csum))
173 return -1;
174 if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
175 netdev_rx_csum_fault(skb->dev);
176 return 0;
177 no_checksum:
178 if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
179 return -1;
180 if (desc.count)
181 return -1;
182 return 0;
184 EXPORT_SYMBOL_GPL(csum_partial_copy_to_xdr);