[net-next-2.6.git] / net / rds / tcp_recv.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 <net/tcp.h>

#include "rds.h"
#include "tcp.h"

static struct kmem_cache *rds_tcp_incoming_slab;

void rds_tcp_inc_purge(struct rds_incoming *inc)
{
	struct rds_tcp_incoming *tinc;
	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	rdsdebug("purging tinc %p inc %p\n", tinc, inc);
	skb_queue_purge(&tinc->ti_skb_list);
}

void rds_tcp_inc_free(struct rds_incoming *inc)
{
	struct rds_tcp_incoming *tinc;
	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	rds_tcp_inc_purge(inc);
	rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
	kmem_cache_free(rds_tcp_incoming_slab, tinc);
}

/*
 * this is pretty lame, but, whatever.
 */
int rds_tcp_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
			     size_t size)
{
	struct rds_tcp_incoming *tinc;
	struct iovec *iov, tmp;
	struct sk_buff *skb;
	unsigned long to_copy, skb_off;
	int ret = 0;

	if (size == 0)
		goto out;

	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	iov = first_iov;
	tmp = *iov;

	skb_queue_walk(&tinc->ti_skb_list, skb) {
		skb_off = 0;
		while (skb_off < skb->len) {
			while (tmp.iov_len == 0) {
				iov++;
				tmp = *iov;
			}

			to_copy = min(tmp.iov_len, size);
			to_copy = min(to_copy, skb->len - skb_off);

			rdsdebug("ret %d size %zu skb %p skb_off %lu "
				 "skblen %d iov_base %p iov_len %zu cpy %lu\n",
				 ret, size, skb, skb_off, skb->len,
				 tmp.iov_base, tmp.iov_len, to_copy);

			/* modifies tmp as it copies */
			if (skb_copy_datagram_iovec(skb, skb_off, &tmp,
						    to_copy)) {
				ret = -EFAULT;
				goto out;
			}

			rds_stats_add(s_copy_to_user, to_copy);
			size -= to_copy;
			ret += to_copy;
			skb_off += to_copy;
			if (size == 0)
				goto out;
		}
	}
out:
	return ret;
}

/*
 * We have a series of skbs that have fragmented pieces of the congestion
 * bitmap.  They must add up to the exact size of the congestion bitmap.  We
 * use the skb helpers to copy those into the pages that make up the in-memory
 * congestion bitmap for the remote address of this connection.  We then tell
 * the congestion core that the bitmap has been changed so that it can wake up
 * sleepers.
 *
 * This is racing with sending paths which are using test_bit to see if the
 * bitmap indicates that their recipient is congested.
 */

static void rds_tcp_cong_recv(struct rds_connection *conn,
			      struct rds_tcp_incoming *tinc)
{
	struct sk_buff *skb;
	unsigned int to_copy, skb_off;
	unsigned int map_off;
	unsigned int map_page;
	struct rds_cong_map *map;
	int ret;

	/* catch completely corrupt packets */
	if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
		return;

	map_page = 0;
	map_off = 0;
	map = conn->c_fcong;

	skb_queue_walk(&tinc->ti_skb_list, skb) {
		skb_off = 0;
		while (skb_off < skb->len) {
			to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
					skb->len - skb_off);

			BUG_ON(map_page >= RDS_CONG_MAP_PAGES);

			/* only returns 0 or -error */
			ret = skb_copy_bits(skb, skb_off,
				(void *)map->m_page_addrs[map_page] + map_off,
				to_copy);
			BUG_ON(ret != 0);

			skb_off += to_copy;
			map_off += to_copy;
			if (map_off == PAGE_SIZE) {
				map_off = 0;
				map_page++;
			}
		}
	}

	rds_cong_map_updated(map, ~(u64) 0);
}

struct rds_tcp_desc_arg {
	struct rds_connection *conn;
	gfp_t gfp;
	enum km_type km;
};

static int rds_tcp_data_recv(read_descriptor_t *desc, struct sk_buff *skb,
			     unsigned int offset, size_t len)
{
	struct rds_tcp_desc_arg *arg = desc->arg.data;
	struct rds_connection *conn = arg->conn;
	struct rds_tcp_connection *tc = conn->c_transport_data;
	struct rds_tcp_incoming *tinc = tc->t_tinc;
	struct sk_buff *clone;
	size_t left = len, to_copy;

	rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
		 len);

	/*
	 * tcp_read_sock() interprets partial progress as an indication to stop
	 * processing.
	 */
	while (left) {
		if (tinc == NULL) {
			tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
					        arg->gfp);
			if (tinc == NULL) {
				desc->error = -ENOMEM;
				goto out;
			}
			tc->t_tinc = tinc;
			rdsdebug("alloced tinc %p\n", tinc);
			rds_inc_init(&tinc->ti_inc, conn, conn->c_faddr);
			/*
			 * XXX * we might be able to use the __ variants when
			 * we've already serialized at a higher level.
			 */
			skb_queue_head_init(&tinc->ti_skb_list);
		}

		if (left && tc->t_tinc_hdr_rem) {
			to_copy = min(tc->t_tinc_hdr_rem, left);
			rdsdebug("copying %zu header from skb %p\n", to_copy,
				 skb);
			skb_copy_bits(skb, offset,
				      (char *)&tinc->ti_inc.i_hdr +
						sizeof(struct rds_header) -
						tc->t_tinc_hdr_rem,
				      to_copy);
			tc->t_tinc_hdr_rem -= to_copy;
			left -= to_copy;
			offset += to_copy;

			if (tc->t_tinc_hdr_rem == 0) {
				/* could be 0 for a 0 len message */
				tc->t_tinc_data_rem =
					be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
			}
		}

		if (left && tc->t_tinc_data_rem) {
			clone = skb_clone(skb, arg->gfp);
			if (clone == NULL) {
				desc->error = -ENOMEM;
				goto out;
			}

			to_copy = min(tc->t_tinc_data_rem, left);
			pskb_pull(clone, offset);
			pskb_trim(clone, to_copy);
			skb_queue_tail(&tinc->ti_skb_list, clone);

			rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
				 "clone %p data %p len %d\n",
				 skb, skb->data, skb->len, offset, to_copy,
				 clone, clone->data, clone->len);

			tc->t_tinc_data_rem -= to_copy;
			left -= to_copy;
			offset += to_copy;
		}

		if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
			if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
				rds_tcp_cong_recv(conn, tinc);
			else
				rds_recv_incoming(conn, conn->c_faddr,
						  conn->c_laddr, &tinc->ti_inc,
						  arg->gfp, arg->km);

			tc->t_tinc_hdr_rem = sizeof(struct rds_header);
			tc->t_tinc_data_rem = 0;
			tc->t_tinc = NULL;
			rds_inc_put(&tinc->ti_inc);
			tinc = NULL;
		}
	}
out:
	rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
		 len, left, skb->len,
		 skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
	return len - left;
}

/* the caller has to hold the sock lock */
int rds_tcp_read_sock(struct rds_connection *conn, gfp_t gfp, enum km_type km)
{
	struct rds_tcp_connection *tc = conn->c_transport_data;
	struct socket *sock = tc->t_sock;
	read_descriptor_t desc;
	struct rds_tcp_desc_arg arg;

	/* It's like glib in the kernel! */
	arg.conn = conn;
	arg.gfp = gfp;
	arg.km = km;
	desc.arg.data = &arg;
	desc.error = 0;
	desc.count = 1; /* give more than one skb per call */

	tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
	rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
		 desc.error);

	return desc.error;
}

/*
 * We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
 * data_ready.
 *
 * if we fail to allocate we're in trouble.. blindly wait some time before
 * trying again to see if the VM can free up something for us.
 */
int rds_tcp_recv(struct rds_connection *conn)
{
	struct rds_tcp_connection *tc = conn->c_transport_data;
	struct socket *sock = tc->t_sock;
	int ret = 0;

	rdsdebug("recv worker conn %p tc %p sock %p\n", conn, tc, sock);

	lock_sock(sock->sk);
	ret = rds_tcp_read_sock(conn, GFP_KERNEL, KM_USER0);
	release_sock(sock->sk);

	return ret;
}

void rds_tcp_data_ready(struct sock *sk, int bytes)
{
	void (*ready)(struct sock *sk, int bytes);
	struct rds_connection *conn;
	struct rds_tcp_connection *tc;

	rdsdebug("data ready sk %p bytes %d\n", sk, bytes);

	read_lock(&sk->sk_callback_lock);
	conn = sk->sk_user_data;
	if (conn == NULL) { /* check for teardown race */
		ready = sk->sk_data_ready;
		goto out;
	}

	tc = conn->c_transport_data;
	ready = tc->t_orig_data_ready;
	rds_tcp_stats_inc(s_tcp_data_ready_calls);

	if (rds_tcp_read_sock(conn, GFP_ATOMIC, KM_SOFTIRQ0) == -ENOMEM)
		queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
out:
	read_unlock(&sk->sk_callback_lock);
	ready(sk, bytes);
}

int __init rds_tcp_recv_init(void)
{
	rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
					sizeof(struct rds_tcp_incoming),
					0, 0, NULL);
	if (rds_tcp_incoming_slab == NULL)
		return -ENOMEM;
	return 0;
}

void rds_tcp_recv_exit(void)
{
	kmem_cache_destroy(rds_tcp_incoming_slab);
}
Commit	Line	Data
70041088 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	#include <net/tcp.h>
	35
	36	#include "rds.h"
	37	#include "tcp.h"
	38
	39	static struct kmem_cache *rds_tcp_incoming_slab;
	40
	41	void rds_tcp_inc_purge(struct rds_incoming *inc)
	42	{
	43	struct rds_tcp_incoming *tinc;
	44	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	45	rdsdebug("purging tinc %p inc %p\n", tinc, inc);
	46	skb_queue_purge(&tinc->ti_skb_list);
	47	}
	48
	49	void rds_tcp_inc_free(struct rds_incoming *inc)
	50	{
	51	struct rds_tcp_incoming *tinc;
	52	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
	53	rds_tcp_inc_purge(inc);
	54	rdsdebug("freeing tinc %p inc %p\n", tinc, inc);
	55	kmem_cache_free(rds_tcp_incoming_slab, tinc);
	56	}
	57
	58	/*
	59	* this is pretty lame, but, whatever.
	60	*/
	61	int rds_tcp_inc_copy_to_user(struct rds_incoming inc, struct iovec first_iov,
	62	size_t size)
	63	{
	64	struct rds_tcp_incoming *tinc;
65	struct iovec *iov, tmp;
66	struct sk_buff *skb;
67	unsigned long to_copy, skb_off;
68	int ret = 0;
69
70	if (size == 0)
71	goto out;
72
73	tinc = container_of(inc, struct rds_tcp_incoming, ti_inc);
74	iov = first_iov;
75	tmp = *iov;
76
77	skb_queue_walk(&tinc->ti_skb_list, skb) {
78	skb_off = 0;
79	while (skb_off < skb->len) {
80	while (tmp.iov_len == 0) {
81	iov++;
82	tmp = *iov;
83	}
84
85	to_copy = min(tmp.iov_len, size);
86	to_copy = min(to_copy, skb->len - skb_off);
87
88	rdsdebug("ret %d size %zu skb %p skb_off %lu "
89	"skblen %d iov_base %p iov_len %zu cpy %lu\n",
90	ret, size, skb, skb_off, skb->len,
91	tmp.iov_base, tmp.iov_len, to_copy);
92
93	/* modifies tmp as it copies */
94	if (skb_copy_datagram_iovec(skb, skb_off, &tmp,
95	to_copy)) {
96	ret = -EFAULT;
97	goto out;
98	}
99
b075cfdb	100	rds_stats_add(s_copy_to_user, to_copy);
70041088 AG	101	size -= to_copy;
	102	ret += to_copy;
	103	skb_off += to_copy;
	104	if (size == 0)
	105	goto out;
	106	}
	107	}
	108	out:
	109	return ret;
	110	}
	111
	112	/*
	113	* We have a series of skbs that have fragmented pieces of the congestion
	114	* bitmap. They must add up to the exact size of the congestion bitmap. We
	115	* use the skb helpers to copy those into the pages that make up the in-memory
	116	* congestion bitmap for the remote address of this connection. We then tell
	117	* the congestion core that the bitmap has been changed so that it can wake up
	118	* sleepers.
	119	*
	120	* This is racing with sending paths which are using test_bit to see if the
	121	* bitmap indicates that their recipient is congested.
	122	*/
	123
	124	static void rds_tcp_cong_recv(struct rds_connection *conn,
	125	struct rds_tcp_incoming *tinc)
	126	{
	127	struct sk_buff *skb;
	128	unsigned int to_copy, skb_off;
	129	unsigned int map_off;
	130	unsigned int map_page;
	131	struct rds_cong_map *map;
	132	int ret;
	133
	134	/* catch completely corrupt packets */
	135	if (be32_to_cpu(tinc->ti_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES)
	136	return;
	137
	138	map_page = 0;
	139	map_off = 0;
	140	map = conn->c_fcong;
	141
	142	skb_queue_walk(&tinc->ti_skb_list, skb) {
	143	skb_off = 0;
	144	while (skb_off < skb->len) {
	145	to_copy = min_t(unsigned int, PAGE_SIZE - map_off,
	146	skb->len - skb_off);
	147
	148	BUG_ON(map_page >= RDS_CONG_MAP_PAGES);
	149
	150	/* only returns 0 or -error */
	151	ret = skb_copy_bits(skb, skb_off,
	152	(void *)map->m_page_addrs[map_page] + map_off,
	153	to_copy);
	154	BUG_ON(ret != 0);
	155
	156	skb_off += to_copy;
	157	map_off += to_copy;
	158	if (map_off == PAGE_SIZE) {
	159	map_off = 0;
	160	map_page++;
	161	}
	162	}
	163	}
	164
165	rds_cong_map_updated(map, ~(u64) 0);
166	}
167
168	struct rds_tcp_desc_arg {
169	struct rds_connection *conn;
170	gfp_t gfp;
171	enum km_type km;
172	};
173
174	static int rds_tcp_data_recv(read_descriptor_t desc, struct sk_buff skb,
175	unsigned int offset, size_t len)
176	{
177	struct rds_tcp_desc_arg *arg = desc->arg.data;
178	struct rds_connection *conn = arg->conn;
179	struct rds_tcp_connection *tc = conn->c_transport_data;
180	struct rds_tcp_incoming *tinc = tc->t_tinc;
181	struct sk_buff *clone;
182	size_t left = len, to_copy;
183
184	rdsdebug("tcp data tc %p skb %p offset %u len %zu\n", tc, skb, offset,
185	len);
186
187	/*
188	* tcp_read_sock() interprets partial progress as an indication to stop
189	* processing.
190	*/
191	while (left) {
192	if (tinc == NULL) {
193	tinc = kmem_cache_alloc(rds_tcp_incoming_slab,
194	arg->gfp);
195	if (tinc == NULL) {
196	desc->error = -ENOMEM;
197	goto out;
198	}
199	tc->t_tinc = tinc;
200	rdsdebug("alloced tinc %p\n", tinc);
201	rds_inc_init(&tinc->ti_inc, conn, conn->c_faddr);
202	/*
203	* XXX * we might be able to use the __ variants when
204	* we've already serialized at a higher level.
205	*/
206	skb_queue_head_init(&tinc->ti_skb_list);
207	}
208
209	if (left && tc->t_tinc_hdr_rem) {
210	to_copy = min(tc->t_tinc_hdr_rem, left);
211	rdsdebug("copying %zu header from skb %p\n", to_copy,
212	skb);
213	skb_copy_bits(skb, offset,
214	(char *)&tinc->ti_inc.i_hdr +
215	sizeof(struct rds_header) -
216	tc->t_tinc_hdr_rem,
217	to_copy);
218	tc->t_tinc_hdr_rem -= to_copy;
219	left -= to_copy;
220	offset += to_copy;
221
222	if (tc->t_tinc_hdr_rem == 0) {
223	/* could be 0 for a 0 len message */
224	tc->t_tinc_data_rem =
225	be32_to_cpu(tinc->ti_inc.i_hdr.h_len);
226	}
227	}
228
229	if (left && tc->t_tinc_data_rem) {
230	clone = skb_clone(skb, arg->gfp);
231	if (clone == NULL) {
232	desc->error = -ENOMEM;
233	goto out;
234	}
235
236	to_copy = min(tc->t_tinc_data_rem, left);
237	pskb_pull(clone, offset);
238	pskb_trim(clone, to_copy);
239	skb_queue_tail(&tinc->ti_skb_list, clone);
240
241	rdsdebug("skb %p data %p len %d off %u to_copy %zu -> "
242	"clone %p data %p len %d\n",
243	skb, skb->data, skb->len, offset, to_copy,
244	clone, clone->data, clone->len);
245
246	tc->t_tinc_data_rem -= to_copy;
247	left -= to_copy;
248	offset += to_copy;
249	}
250
251	if (tc->t_tinc_hdr_rem == 0 && tc->t_tinc_data_rem == 0) {
252	if (tinc->ti_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
253	rds_tcp_cong_recv(conn, tinc);
254	else
255	rds_recv_incoming(conn, conn->c_faddr,
256	conn->c_laddr, &tinc->ti_inc,
257	arg->gfp, arg->km);
258
259	tc->t_tinc_hdr_rem = sizeof(struct rds_header);
260	tc->t_tinc_data_rem = 0;
261	tc->t_tinc = NULL;
262	rds_inc_put(&tinc->ti_inc);
263	tinc = NULL;
264	}
265	}
266	out:
267	rdsdebug("returning len %zu left %zu skb len %d rx queue depth %d\n",
268	len, left, skb->len,
269	skb_queue_len(&tc->t_sock->sk->sk_receive_queue));
270	return len - left;
271	}
272
273	/* the caller has to hold the sock lock */
274	int rds_tcp_read_sock(struct rds_connection *conn, gfp_t gfp, enum km_type km)
275	{
276	struct rds_tcp_connection *tc = conn->c_transport_data;
277	struct socket *sock = tc->t_sock;
278	read_descriptor_t desc;
279	struct rds_tcp_desc_arg arg;
280
281	/* It's like glib in the kernel! */
282	arg.conn = conn;
283	arg.gfp = gfp;
284	arg.km = km;
285	desc.arg.data = &arg;
286	desc.error = 0;
287	desc.count = 1; /* give more than one skb per call */
288
289	tcp_read_sock(sock->sk, &desc, rds_tcp_data_recv);
290	rdsdebug("tcp_read_sock for tc %p gfp 0x%x returned %d\n", tc, gfp,
291	desc.error);
292
293	return desc.error;
294	}
295
296	/*
297	* We hold the sock lock to serialize our rds_tcp_recv->tcp_read_sock from
298	* data_ready.
299	*
300	* if we fail to allocate we're in trouble.. blindly wait some time before
301	* trying again to see if the VM can free up something for us.
302	*/
303	int rds_tcp_recv(struct rds_connection *conn)
304	{
305	struct rds_tcp_connection *tc = conn->c_transport_data;
306	struct socket *sock = tc->t_sock;
307	int ret = 0;
308
309	rdsdebug("recv worker conn %p tc %p sock %p\n", conn, tc, sock);
310
311	lock_sock(sock->sk);
312	ret = rds_tcp_read_sock(conn, GFP_KERNEL, KM_USER0);
313	release_sock(sock->sk);
314
315	return ret;
316	}
317
318	void rds_tcp_data_ready(struct sock *sk, int bytes)
319	{
320	void (ready)(struct sock sk, int bytes);
321	struct rds_connection *conn;
322	struct rds_tcp_connection *tc;
323
324	rdsdebug("data ready sk %p bytes %d\n", sk, bytes);
325
326	read_lock(&sk->sk_callback_lock);
327	conn = sk->sk_user_data;
328	if (conn == NULL) { /* check for teardown race */
329	ready = sk->sk_data_ready;
330	goto out;
331	}
332
333	tc = conn->c_transport_data;
334	ready = tc->t_orig_data_ready;
335	rds_tcp_stats_inc(s_tcp_data_ready_calls);
336
337	if (rds_tcp_read_sock(conn, GFP_ATOMIC, KM_SOFTIRQ0) == -ENOMEM)
338	queue_delayed_work(rds_wq, &conn->c_recv_w, 0);
339	out:
340	read_unlock(&sk->sk_callback_lock);
341	ready(sk, bytes);
342	}
343
344	int __init rds_tcp_recv_init(void)
345	{
346	rds_tcp_incoming_slab = kmem_cache_create("rds_tcp_incoming",
347	sizeof(struct rds_tcp_incoming),
348	0, 0, NULL);
349	if (rds_tcp_incoming_slab == NULL)
350	return -ENOMEM;
351	return 0;
352	}
353
354	void rds_tcp_recv_exit(void)
355	{
356	kmem_cache_destroy(rds_tcp_incoming_slab);
357	}