linux/net/rds/message.c

/*
 * Copyright (c) 2006, 2020 Oracle and/or its affiliates.
 *
 * 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 <linux/slab.h>
#include <linux/export.h>
#include <linux/skbuff.h>
#include <linux/list.h>
#include <linux/errqueue.h>

#include "rds.h"

static unsigned int	rds_exthdr_size[__RDS_EXTHDR_MAX] = …;

void rds_message_addref(struct rds_message *rm)
{ … }
EXPORT_SYMBOL_GPL(…);

static inline bool rds_zcookie_add(struct rds_msg_zcopy_info *info, u32 cookie)
{ … }

static struct rds_msg_zcopy_info *rds_info_from_znotifier(struct rds_znotifier *znotif)
{ … }

void rds_notify_msg_zcopy_purge(struct rds_msg_zcopy_queue *q)
{ … }

static void rds_rm_zerocopy_callback(struct rds_sock *rs,
				     struct rds_znotifier *znotif)
{ … }

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

void rds_message_put(struct rds_message *rm)
{ … }
EXPORT_SYMBOL_GPL(…);

void rds_message_populate_header(struct rds_header *hdr, __be16 sport,
				 __be16 dport, u64 seq)
{ … }
EXPORT_SYMBOL_GPL(…);

int rds_message_add_extension(struct rds_header *hdr, unsigned int type,
			      const void *data, unsigned int len)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * 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)
{ … }

int rds_message_add_rdma_dest_extension(struct rds_header *hdr, u32 r_key, u32 offset)
{ … }
EXPORT_SYMBOL_GPL(…);

/*
 * Each rds_message is allocated with extra space for the scatterlist entries
 * rds ops will need. This is to minimize memory allocation count. Then, each rds op
 * can grab SGs when initializing its part of the rds_message.
 */
struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
{ … }

/*
 * RDS ops use this to grab SG entries from the rm's sg pool.
 */
struct scatterlist *rds_message_alloc_sgs(struct rds_message *rm, int nents)
{ … }

struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned int total_len)
{ … }

static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter *from)
{ … }

int rds_message_copy_from_user(struct rds_message *rm, struct iov_iter *from,
			       bool zcopy)
{ … }

int rds_message_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
{ … }

/*
 * 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)
{ … }

void rds_message_unmapped(struct rds_message *rm)
{ … }
EXPORT_SYMBOL_GPL(…);