[linux-block.git] / net / rds / message.c

/*
 * Copyright (c) 2006 Oracle.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/kernel.h>

#include "rds.h"
#include "rdma.h"

static DECLARE_WAIT_QUEUE_HEAD(rds_message_flush_waitq);

static unsigned int	rds_exthdr_size[__RDS_EXTHDR_MAX] = {
[RDS_EXTHDR_NONE]	= 0,
[RDS_EXTHDR_VERSION]	= sizeof(struct rds_ext_header_version),
[RDS_EXTHDR_RDMA]	= sizeof(struct rds_ext_header_rdma),
[RDS_EXTHDR_RDMA_DEST]	= sizeof(struct rds_ext_header_rdma_dest),
};


void rds_message_addref(struct rds_message *rm)
{
	rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
	atomic_inc(&rm->m_refcount);
}

/*
 * This relies on dma_map_sg() not touching sg[].page during merging.
 */
static void rds_message_purge(struct rds_message *rm)
{
	unsigned long i;

	if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
		return;

	for (i = 0; i < rm->m_nents; i++) {
		rdsdebug("putting data page %p\n", (void *)sg_page(&rm->m_sg[i]));
		/* XXX will have to put_page for page refs */
		__free_page(sg_page(&rm->m_sg[i]));
	}
	rm->m_nents = 0;

	if (rm->m_rdma_op)
		rds_rdma_free_op(rm->m_rdma_op);
	if (rm->m_rdma_mr)
		rds_mr_put(rm->m_rdma_mr);
}

void rds_message_inc_purge(struct rds_incoming *inc)
{
	struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
	rds_message_purge(rm);
}

void rds_message_put(struct rds_message *rm)
{
	rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));

	if (atomic_dec_and_test(&rm->m_refcount)) {
		BUG_ON(!list_empty(&rm->m_sock_item));
		BUG_ON(!list_empty(&rm->m_conn_item));
		rds_message_purge(rm);

		kfree(rm);
	}
}

void rds_message_inc_free(struct rds_incoming *inc)
{
	struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
	rds_message_put(rm);
}

void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
				 __be16 dport, u64 seq)
{
	hdr->h_flags = 0;
	hdr->h_sport = sport;
	hdr->h_dport = dport;
	hdr->h_sequence = cpu_to_be64(seq);
	hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
}

int rds_message_add_extension(struct rds_header *hdr,
		unsigned int type, const void *data, unsigned int len)
{
	unsigned int ext_len = sizeof(u8) + len;
	unsigned char *dst;

	/* For now, refuse to add more than one extension header */
	if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
		return 0;

	if (type >= __RDS_EXTHDR_MAX
	 || len != rds_exthdr_size[type])
		return 0;

	if (ext_len >= RDS_HEADER_EXT_SPACE)
		return 0;
	dst = hdr->h_exthdr;

	*dst++ = type;
	memcpy(dst, data, len);

	dst[len] = RDS_EXTHDR_NONE;
	return 1;
}

/*
 * If a message has extension headers, retrieve them here.
 * Call like this:
 *
 * unsigned int pos = 0;
 *
 * while (1) {
 *	buflen = sizeof(buffer);
 *	type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
 *	if (type == RDS_EXTHDR_NONE)
 *		break;
 *	...
 * }
 */
int rds_message_next_extension(struct rds_header *hdr,
		unsigned int *pos, void *buf, unsigned int *buflen)
{
	unsigned int offset, ext_type, ext_len;
	u8 *src = hdr->h_exthdr;

	offset = *pos;
	if (offset >= RDS_HEADER_EXT_SPACE)
		goto none;

	/* Get the extension type and length. For now, the
	 * length is implied by the extension type. */
	ext_type = src[offset++];

	if (ext_type == RDS_EXTHDR_NONE || ext_type >= __RDS_EXTHDR_MAX)
		goto none;
	ext_len = rds_exthdr_size[ext_type];
	if (offset + ext_len > RDS_HEADER_EXT_SPACE)
		goto none;

	*pos = offset + ext_len;
	if (ext_len < *buflen)
		*buflen = ext_len;
	memcpy(buf, src + offset, *buflen);
	return ext_type;

none:
	*pos = RDS_HEADER_EXT_SPACE;
	*buflen = 0;
	return RDS_EXTHDR_NONE;
}

int rds_message_add_version_extension(struct rds_header *hdr, unsigned int version)
{
	struct rds_ext_header_version ext_hdr;

	ext_hdr.h_version = cpu_to_be32(version);
	return rds_message_add_extension(hdr, RDS_EXTHDR_VERSION, &ext_hdr, sizeof(ext_hdr));
}

int rds_message_get_version_extension(struct rds_header *hdr, unsigned int *version)
{
	struct rds_ext_header_version ext_hdr;
	unsigned int pos = 0, len = sizeof(ext_hdr);

	/* We assume the version extension is the only one present */
	if (rds_message_next_extension(hdr, &pos, &ext_hdr, &len) != RDS_EXTHDR_VERSION)
		return 0;
	*version = be32_to_cpu(ext_hdr.h_version);
	return 1;
}

int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
{
	struct rds_ext_header_rdma_dest ext_hdr;

	ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
	ext_hdr.h_rdma_offset = cpu_to_be32(offset);
	return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
}

struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp)
{
	struct rds_message *rm;

	rm = kzalloc(sizeof(struct rds_message) +
		     (nents * sizeof(struct scatterlist)), gfp);
	if (!rm)
		goto out;

	if (nents)
		sg_init_table(rm->m_sg, nents);
	atomic_set(&rm->m_refcount, 1);
	INIT_LIST_HEAD(&rm->m_sock_item);
	INIT_LIST_HEAD(&rm->m_conn_item);
	spin_lock_init(&rm->m_rs_lock);

out:
	return rm;
}

struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
{
	struct rds_message *rm;
	unsigned int i;

	rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
	if (rm == NULL)
		return ERR_PTR(-ENOMEM);

	set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
	rm->m_nents = ceil(total_len, PAGE_SIZE);

	for (i = 0; i < rm->m_nents; ++i) {
		sg_set_page(&rm->m_sg[i],
				virt_to_page(page_addrs[i]),
				PAGE_SIZE, 0);
	}

	return rm;
}

struct rds_message *rds_message_copy_from_user(struct iovec *first_iov,
					       size_t total_len)
{
	unsigned long to_copy;
	unsigned long iov_off;
	unsigned long sg_off;
	struct rds_message *rm;
	struct iovec *iov;
	struct scatterlist *sg;
	int ret;

	rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
	if (rm == NULL) {
		ret = -ENOMEM;
		goto out;
	}

	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);

	/*
	 * now allocate and copy in the data payload.
	 */
	sg = rm->m_sg;
	iov = first_iov;
	iov_off = 0;
	sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */

	while (total_len) {
		if (sg_page(sg) == NULL) {
			ret = rds_page_remainder_alloc(sg, total_len,
						       GFP_HIGHUSER);
			if (ret)
				goto out;
			rm->m_nents++;
			sg_off = 0;
		}

		while (iov_off == iov->iov_len) {
			iov_off = 0;
			iov++;
		}

		to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
		to_copy = min_t(size_t, to_copy, total_len);

		rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
			 "sg [%p, %u, %u] + %lu\n",
			 to_copy, iov->iov_base, iov->iov_len, iov_off,
			 (void *)sg_page(sg), sg->offset, sg->length, sg_off);

		ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
					      iov->iov_base + iov_off,
					      to_copy);
		if (ret)
			goto out;

		iov_off += to_copy;
		total_len -= to_copy;
		sg_off += to_copy;

		if (sg_off == sg->length)
			sg++;
	}

	ret = 0;
out:
	if (ret) {
		if (rm)
			rds_message_put(rm);
		rm = ERR_PTR(ret);
	}
	return rm;
}

int rds_message_inc_copy_to_user(struct rds_incoming *inc,
				 struct iovec *first_iov, size_t size)
{
	struct rds_message *rm;
	struct iovec *iov;
	struct scatterlist *sg;
	unsigned long to_copy;
	unsigned long iov_off;
	unsigned long vec_off;
	int copied;
	int ret;
	u32 len;

	rm = container_of(inc, struct rds_message, m_inc);
	len = be32_to_cpu(rm->m_inc.i_hdr.h_len);

	iov = first_iov;
	iov_off = 0;
	sg = rm->m_sg;
	vec_off = 0;
	copied = 0;

	while (copied < size && copied < len) {
		while (iov_off == iov->iov_len) {
			iov_off = 0;
			iov++;
		}

		to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
		to_copy = min_t(size_t, to_copy, size - copied);
		to_copy = min_t(unsigned long, to_copy, len - copied);

		rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
			 "sg [%p, %u, %u] + %lu\n",
			 to_copy, iov->iov_base, iov->iov_len, iov_off,
			 sg_page(sg), sg->offset, sg->length, vec_off);

		ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
					    iov->iov_base + iov_off,
					    to_copy);
		if (ret) {
			copied = ret;
			break;
		}

		iov_off += to_copy;
		vec_off += to_copy;
		copied += to_copy;

		if (vec_off == sg->length) {
			vec_off = 0;
			sg++;
		}
	}

	return copied;
}

/*
 * If the message is still on the send queue, wait until the transport
 * is done with it. This is particularly important for RDMA operations.
 */
void rds_message_wait(struct rds_message *rm)
{
	wait_event(rds_message_flush_waitq,
			!test_bit(RDS_MSG_MAPPED, &rm->m_flags));
}

void rds_message_unmapped(struct rds_message *rm)
{
	clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
	if (waitqueue_active(&rds_message_flush_waitq))
		wake_up(&rds_message_flush_waitq);
}
Commit	Line	Data
7875e18e AG	1	/*
	2	* Copyright (c) 2006 Oracle. All rights reserved.
	3	*
	4	* This software is available to you under a choice of one of two
	5	* licenses. You may choose to be licensed under the terms of the GNU
	6	* General Public License (GPL) Version 2, available from the file
	7	* COPYING in the main directory of this source tree, or the
	8	* OpenIB.org BSD license below:
	9	*
	10	* Redistribution and use in source and binary forms, with or
	11	* without modification, are permitted provided that the following
	12	* conditions are met:
	13	*
	14	* - Redistributions of source code must retain the above
	15	* copyright notice, this list of conditions and the following
	16	* disclaimer.
	17	*
	18	* - Redistributions in binary form must reproduce the above
	19	* copyright notice, this list of conditions and the following
	20	* disclaimer in the documentation and/or other materials
	21	* provided with the distribution.
	22	*
	23	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	24	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	25	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	26	* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
	27	* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
	28	* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	29	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	30	* SOFTWARE.
	31	*
	32	*/
	33	#include <linux/kernel.h>
	34
	35	#include "rds.h"
	36	#include "rdma.h"
	37
	38	static DECLARE_WAIT_QUEUE_HEAD(rds_message_flush_waitq);
	39
	40	static unsigned int rds_exthdr_size[__RDS_EXTHDR_MAX] = {
	41	[RDS_EXTHDR_NONE] = 0,
	42	[RDS_EXTHDR_VERSION] = sizeof(struct rds_ext_header_version),
	43	[RDS_EXTHDR_RDMA] = sizeof(struct rds_ext_header_rdma),
	44	[RDS_EXTHDR_RDMA_DEST] = sizeof(struct rds_ext_header_rdma_dest),
	45	};
	46
	47
	48	void rds_message_addref(struct rds_message *rm)
	49	{
	50	rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
	51	atomic_inc(&rm->m_refcount);
	52	}
	53
	54	/*
	55	* This relies on dma_map_sg() not touching sg[].page during merging.
	56	*/
	57	static void rds_message_purge(struct rds_message *rm)
	58	{
	59	unsigned long i;
	60
	61	if (unlikely(test_bit(RDS_MSG_PAGEVEC, &rm->m_flags)))
	62	return;
	63
	64	for (i = 0; i < rm->m_nents; i++) {
65	rdsdebug("putting data page %p\n", (void *)sg_page(&rm->m_sg[i]));
66	/* XXX will have to put_page for page refs */
67	__free_page(sg_page(&rm->m_sg[i]));
68	}
69	rm->m_nents = 0;
70
71	if (rm->m_rdma_op)
72	rds_rdma_free_op(rm->m_rdma_op);
73	if (rm->m_rdma_mr)
74	rds_mr_put(rm->m_rdma_mr);
75	}
76
77	void rds_message_inc_purge(struct rds_incoming *inc)
78	{
79	struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
80	rds_message_purge(rm);
81	}
82
83	void rds_message_put(struct rds_message *rm)
84	{
85	rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));
86
87	if (atomic_dec_and_test(&rm->m_refcount)) {
88	BUG_ON(!list_empty(&rm->m_sock_item));
89	BUG_ON(!list_empty(&rm->m_conn_item));
90	rds_message_purge(rm);
91
92	kfree(rm);
93	}
94	}
95
96	void rds_message_inc_free(struct rds_incoming *inc)
97	{
98	struct rds_message *rm = container_of(inc, struct rds_message, m_inc);
99	rds_message_put(rm);
100	}
101
102	void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
103	__be16 dport, u64 seq)
104	{
105	hdr->h_flags = 0;
106	hdr->h_sport = sport;
107	hdr->h_dport = dport;
108	hdr->h_sequence = cpu_to_be64(seq);
109	hdr->h_exthdr[0] = RDS_EXTHDR_NONE;
110	}
111
112	int rds_message_add_extension(struct rds_header *hdr,
113	unsigned int type, const void *data, unsigned int len)
114	{
115	unsigned int ext_len = sizeof(u8) + len;
116	unsigned char *dst;
117
118	/* For now, refuse to add more than one extension header */
119	if (hdr->h_exthdr[0] != RDS_EXTHDR_NONE)
120	return 0;
121
122	if (type >= __RDS_EXTHDR_MAX
123	\|\| len != rds_exthdr_size[type])
124	return 0;
125
126	if (ext_len >= RDS_HEADER_EXT_SPACE)
127	return 0;
128	dst = hdr->h_exthdr;
129
130	*dst++ = type;
131	memcpy(dst, data, len);
132
133	dst[len] = RDS_EXTHDR_NONE;
134	return 1;
135	}
136
137	/*
138	* If a message has extension headers, retrieve them here.
139	* Call like this:
140	*
141	* unsigned int pos = 0;
142	*
143	* while (1) {
144	* buflen = sizeof(buffer);
145	* type = rds_message_next_extension(hdr, &pos, buffer, &buflen);
146	* if (type == RDS_EXTHDR_NONE)
147	* break;
148	* ...
149	* }
150	*/
151	int rds_message_next_extension(struct rds_header *hdr,
152	unsigned int pos, void buf, unsigned int *buflen)
153	{
154	unsigned int offset, ext_type, ext_len;
155	u8 *src = hdr->h_exthdr;
156
157	offset = *pos;
158	if (offset >= RDS_HEADER_EXT_SPACE)
159	goto none;
160
161	/* Get the extension type and length. For now, the
162	* length is implied by the extension type. */
163	ext_type = src[offset++];
164
165	if (ext_type == RDS_EXTHDR_NONE \|\| ext_type >= __RDS_EXTHDR_MAX)
166	goto none;
167	ext_len = rds_exthdr_size[ext_type];
168	if (offset + ext_len > RDS_HEADER_EXT_SPACE)
169	goto none;
170
171	*pos = offset + ext_len;
172	if (ext_len < *buflen)
173	*buflen = ext_len;
174	memcpy(buf, src + offset, *buflen);
175	return ext_type;
176
177	none:
178	*pos = RDS_HEADER_EXT_SPACE;
179	*buflen = 0;
180	return RDS_EXTHDR_NONE;
181	}
182
183	int rds_message_add_version_extension(struct rds_header *hdr, unsigned int version)
184	{
185	struct rds_ext_header_version ext_hdr;
186
187	ext_hdr.h_version = cpu_to_be32(version);
188	return rds_message_add_extension(hdr, RDS_EXTHDR_VERSION, &ext_hdr, sizeof(ext_hdr));
189	}
190
191	int rds_message_get_version_extension(struct rds_header hdr, unsigned int version)
192	{
193	struct rds_ext_header_version ext_hdr;
194	unsigned int pos = 0, len = sizeof(ext_hdr);
195
196	/* We assume the version extension is the only one present */
197	if (rds_message_next_extension(hdr, &pos, &ext_hdr, &len) != RDS_EXTHDR_VERSION)
198	return 0;
199	*version = be32_to_cpu(ext_hdr.h_version);
200	return 1;
201	}
202
203	int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
204	{
205	struct rds_ext_header_rdma_dest ext_hdr;
206
207	ext_hdr.h_rdma_rkey = cpu_to_be32(r_key);
208	ext_hdr.h_rdma_offset = cpu_to_be32(offset);
209	return rds_message_add_extension(hdr, RDS_EXTHDR_RDMA_DEST, &ext_hdr, sizeof(ext_hdr));
210	}
211
212	struct rds_message *rds_message_alloc(unsigned int nents, gfp_t gfp)
213	{
214	struct rds_message *rm;
215
216	rm = kzalloc(sizeof(struct rds_message) +
217	(nents * sizeof(struct scatterlist)), gfp);
218	if (!rm)
219	goto out;
220
221	if (nents)
222	sg_init_table(rm->m_sg, nents);
223	atomic_set(&rm->m_refcount, 1);
224	INIT_LIST_HEAD(&rm->m_sock_item);
225	INIT_LIST_HEAD(&rm->m_conn_item);
226	spin_lock_init(&rm->m_rs_lock);
227
228	out:
229	return rm;
230	}
231
232	struct rds_message rds_message_map_pages(unsigned long page_addrs, unsigned int total_len)
233	{
234	struct rds_message *rm;
235	unsigned int i;
236
237	rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
238	if (rm == NULL)
239	return ERR_PTR(-ENOMEM);
240
241	set_bit(RDS_MSG_PAGEVEC, &rm->m_flags);
242	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
243	rm->m_nents = ceil(total_len, PAGE_SIZE);
244
245	for (i = 0; i < rm->m_nents; ++i) {
246	sg_set_page(&rm->m_sg[i],
247	virt_to_page(page_addrs[i]),
248	PAGE_SIZE, 0);
249	}
250
251	return rm;
252	}
253
254	struct rds_message rds_message_copy_from_user(struct iovec first_iov,
255	size_t total_len)
256	{
257	unsigned long to_copy;
258	unsigned long iov_off;
259	unsigned long sg_off;
260	struct rds_message *rm;
261	struct iovec *iov;
262	struct scatterlist *sg;
263	int ret;
264
265	rm = rds_message_alloc(ceil(total_len, PAGE_SIZE), GFP_KERNEL);
266	if (rm == NULL) {
267	ret = -ENOMEM;
268	goto out;
269	}
270
271	rm->m_inc.i_hdr.h_len = cpu_to_be32(total_len);
272
273	/*
274	* now allocate and copy in the data payload.
275	*/
276	sg = rm->m_sg;
277	iov = first_iov;
278	iov_off = 0;
279	sg_off = 0; /* Dear gcc, sg->page will be null from kzalloc. */
280
281	while (total_len) {
282	if (sg_page(sg) == NULL) {
283	ret = rds_page_remainder_alloc(sg, total_len,
284	GFP_HIGHUSER);
285	if (ret)
286	goto out;
287	rm->m_nents++;
288	sg_off = 0;
289	}
290
291	while (iov_off == iov->iov_len) {
292	iov_off = 0;
293	iov++;
294	}
295
296	to_copy = min(iov->iov_len - iov_off, sg->length - sg_off);
297	to_copy = min_t(size_t, to_copy, total_len);
298
299	rdsdebug("copying %lu bytes from user iov [%p, %zu] + %lu to "
300	"sg [%p, %u, %u] + %lu\n",
301	to_copy, iov->iov_base, iov->iov_len, iov_off,
302	(void *)sg_page(sg), sg->offset, sg->length, sg_off);
303
304	ret = rds_page_copy_from_user(sg_page(sg), sg->offset + sg_off,
305	iov->iov_base + iov_off,
306	to_copy);
307	if (ret)
308	goto out;
309
310	iov_off += to_copy;
311	total_len -= to_copy;
312	sg_off += to_copy;
313
314	if (sg_off == sg->length)
315	sg++;
316	}
317
318	ret = 0;
319	out:
320	if (ret) {
321	if (rm)
322	rds_message_put(rm);
323	rm = ERR_PTR(ret);
324	}
325	return rm;
326	}
327
328	int rds_message_inc_copy_to_user(struct rds_incoming *inc,
329	struct iovec *first_iov, size_t size)
330	{
331	struct rds_message *rm;
332	struct iovec *iov;
333	struct scatterlist *sg;
334	unsigned long to_copy;
335	unsigned long iov_off;
336	unsigned long vec_off;
337	int copied;
338	int ret;
339	u32 len;
340
341	rm = container_of(inc, struct rds_message, m_inc);
342	len = be32_to_cpu(rm->m_inc.i_hdr.h_len);
343
344	iov = first_iov;
345	iov_off = 0;
346	sg = rm->m_sg;
347	vec_off = 0;
348	copied = 0;
349
350	while (copied < size && copied < len) {
351	while (iov_off == iov->iov_len) {
352	iov_off = 0;
353	iov++;
354	}
355
356	to_copy = min(iov->iov_len - iov_off, sg->length - vec_off);
357	to_copy = min_t(size_t, to_copy, size - copied);
358	to_copy = min_t(unsigned long, to_copy, len - copied);
359
360	rdsdebug("copying %lu bytes to user iov [%p, %zu] + %lu to "
361	"sg [%p, %u, %u] + %lu\n",
362	to_copy, iov->iov_base, iov->iov_len, iov_off,
363	sg_page(sg), sg->offset, sg->length, vec_off);
364
365	ret = rds_page_copy_to_user(sg_page(sg), sg->offset + vec_off,
366	iov->iov_base + iov_off,
367	to_copy);
368	if (ret) {
369	copied = ret;
370	break;
371	}
372
373	iov_off += to_copy;
374	vec_off += to_copy;
375	copied += to_copy;
376
377	if (vec_off == sg->length) {
378	vec_off = 0;
379	sg++;
380	}
381	}
382
383	return copied;
384	}
385
386	/*
387	* If the message is still on the send queue, wait until the transport
388	* is done with it. This is particularly important for RDMA operations.
389	*/
390	void rds_message_wait(struct rds_message *rm)
391	{
392	wait_event(rds_message_flush_waitq,
393	!test_bit(RDS_MSG_MAPPED, &rm->m_flags));
394	}
395
396	void rds_message_unmapped(struct rds_message *rm)
397	{
398	clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
399	if (waitqueue_active(&rds_message_flush_waitq))
400	wake_up(&rds_message_flush_waitq);
401	}
402