linux/net/rds/rdma.c

/*
 * Copyright (c) 2007, 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/pagemap.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/dma-mapping.h> /* for DMA_*_DEVICE */

#include "rds.h"

/*
 * XXX
 *  - build with sparse
 *  - should we detect duplicate keys on a socket?  hmm.
 *  - an rdma is an mlock, apply rlimit?
 */

/*
 * get the number of pages by looking at the page indices that the start and
 * end addresses fall in.
 *
 * Returns 0 if the vec is invalid.  It is invalid if the number of bytes
 * causes the address to wrap or overflows an unsigned int.  This comes
 * from being stored in the 'length' member of 'struct scatterlist'.
 */
static unsigned int rds_pages_in_vec(struct rds_iovec *vec)
{ … }

static struct rds_mr *rds_mr_tree_walk(struct rb_root *root, u64 key,
				       struct rds_mr *insert)
{ … }

/*
 * Destroy the transport-specific part of a MR.
 */
static void rds_destroy_mr(struct rds_mr *mr)
{ … }

void __rds_put_mr_final(struct kref *kref)
{ … }

/*
 * By the time this is called we can't have any more ioctls called on
 * the socket so we don't need to worry about racing with others.
 */
void rds_rdma_drop_keys(struct rds_sock *rs)
{ … }

/*
 * Helper function to pin user pages.
 */
static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,
			struct page **pages, int write)
{ … }

static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args,
			  u64 *cookie_ret, struct rds_mr **mr_ret,
			  struct rds_conn_path *cp)
{ … }

int rds_get_mr(struct rds_sock *rs, sockptr_t optval, int optlen)
{ … }

int rds_get_mr_for_dest(struct rds_sock *rs, sockptr_t optval, int optlen)
{ … }

/*
 * Free the MR indicated by the given R_Key
 */
int rds_free_mr(struct rds_sock *rs, sockptr_t optval, int optlen)
{ … }

/*
 * This is called when we receive an extension header that
 * tells us this MR was used. It allows us to implement
 * use_once semantics
 */
void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force)
{ … }

void rds_rdma_free_op(struct rm_rdma_op *ro)
{ … }

void rds_atomic_free_op(struct rm_atomic_op *ao)
{ … }


/*
 * Count the number of pages needed to describe an incoming iovec array.
 */
static int rds_rdma_pages(struct rds_iovec iov[], int nr_iovecs)
{ … }

int rds_rdma_extra_size(struct rds_rdma_args *args,
			struct rds_iov_vector *iov)
{ … }

/*
 * The application asks for a RDMA transfer.
 * Extract all arguments and set up the rdma_op
 */
int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
		       struct cmsghdr *cmsg,
		       struct rds_iov_vector *vec)
{ … }

/*
 * The application wants us to pass an RDMA destination (aka MR)
 * to the remote
 */
int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
			  struct cmsghdr *cmsg)
{ … }

/*
 * The application passes us an address range it wants to enable RDMA
 * to/from. We map the area, and save the <R_Key,offset> pair
 * in rm->m_rdma_cookie. This causes it to be sent along to the peer
 * in an extension header.
 */
int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
			  struct cmsghdr *cmsg)
{ … }

/*
 * Fill in rds_message for an atomic request.
 */
int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
		    struct cmsghdr *cmsg)
{ … }