[ofa-general] [PATCH 12/26] RDS: RDMA support
Andy Grover
andy.grover at oracle.com
Tue Feb 24 17:30:29 PST 2009
Some transports may support RDMA features. This handles the
non-transport-specific parts, like pinning user pages and
tracking mapped regions.
Signed-off-by: Andy Grover <andy.grover at oracle.com>
---
net/rds/rdma.c | 679 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
net/rds/rdma.h | 84 +++++++
2 files changed, 763 insertions(+), 0 deletions(-)
create mode 100644 net/rds/rdma.c
create mode 100644 net/rds/rdma.h
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
new file mode 100644
index 0000000..eaeeb91
--- /dev/null
+++ b/net/rds/rdma.c
@@ -0,0 +1,679 @@
+/*
+ * Copyright (c) 2007 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/pagemap.h>
+#include <linux/rbtree.h>
+#include <linux/dma-mapping.h> /* for DMA_*_DEVICE */
+
+#include "rdma.h"
+
+/*
+ * XXX
+ * - build with sparse
+ * - should we limit the size of a mr region? let transport return failure?
+ * - 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)
+{
+ if ((vec->addr + vec->bytes <= vec->addr) ||
+ (vec->bytes > (u64)UINT_MAX))
+ return 0;
+
+ return ((vec->addr + vec->bytes + PAGE_SIZE - 1) >> PAGE_SHIFT) -
+ (vec->addr >> PAGE_SHIFT);
+}
+
+static struct rds_mr *rds_mr_tree_walk(struct rb_root *root, u64 key,
+ struct rds_mr *insert)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ struct rds_mr *mr;
+
+ while (*p) {
+ parent = *p;
+ mr = rb_entry(parent, struct rds_mr, r_rb_node);
+
+ if (key < mr->r_key)
+ p = &(*p)->rb_left;
+ else if (key > mr->r_key)
+ p = &(*p)->rb_right;
+ else
+ return mr;
+ }
+
+ if (insert) {
+ rb_link_node(&insert->r_rb_node, parent, p);
+ rb_insert_color(&insert->r_rb_node, root);
+ atomic_inc(&insert->r_refcount);
+ }
+ return NULL;
+}
+
+/*
+ * Destroy the transport-specific part of a MR.
+ */
+static void rds_destroy_mr(struct rds_mr *mr)
+{
+ struct rds_sock *rs = mr->r_sock;
+ void *trans_private = NULL;
+ unsigned long flags;
+
+ rdsdebug("RDS: destroy mr key is %x refcnt %u\n",
+ mr->r_key, atomic_read(&mr->r_refcount));
+
+ if (test_and_set_bit(RDS_MR_DEAD, &mr->r_state))
+ return;
+
+ spin_lock_irqsave(&rs->rs_rdma_lock, flags);
+ if (!RB_EMPTY_NODE(&mr->r_rb_node))
+ rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
+ trans_private = mr->r_trans_private;
+ mr->r_trans_private = NULL;
+ spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
+
+ if (trans_private)
+ mr->r_trans->free_mr(trans_private, mr->r_invalidate);
+}
+
+void __rds_put_mr_final(struct rds_mr *mr)
+{
+ rds_destroy_mr(mr);
+ kfree(mr);
+}
+
+/*
+ * 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)
+{
+ struct rds_mr *mr;
+ struct rb_node *node;
+
+ /* Release any MRs associated with this socket */
+ while ((node = rb_first(&rs->rs_rdma_keys))) {
+ mr = container_of(node, struct rds_mr, r_rb_node);
+ if (mr->r_trans == rs->rs_transport)
+ mr->r_invalidate = 0;
+ rds_mr_put(mr);
+ }
+
+ if (rs->rs_transport && rs->rs_transport->flush_mrs)
+ rs->rs_transport->flush_mrs();
+}
+
+/*
+ * Helper function to pin user pages.
+ */
+static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,
+ struct page **pages, int write)
+{
+ int ret;
+
+ down_read(¤t->mm->mmap_sem);
+ ret = get_user_pages(current, current->mm, user_addr,
+ nr_pages, write, 0, pages, NULL);
+ up_read(¤t->mm->mmap_sem);
+
+ if (0 <= ret && (unsigned) ret < nr_pages) {
+ while (ret--)
+ put_page(pages[ret]);
+ ret = -EFAULT;
+ }
+
+ return ret;
+}
+
+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_mr *mr = NULL, *found;
+ unsigned int nr_pages;
+ struct page **pages = NULL;
+ struct scatterlist *sg;
+ void *trans_private;
+ unsigned long flags;
+ rds_rdma_cookie_t cookie;
+ unsigned int nents;
+ long i;
+ int ret;
+
+ if (rs->rs_bound_addr == 0) {
+ ret = -ENOTCONN; /* XXX not a great errno */
+ goto out;
+ }
+
+ if (rs->rs_transport->get_mr == NULL) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+
+ nr_pages = rds_pages_in_vec(&args->vec);
+ if (nr_pages == 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ rdsdebug("RDS: get_mr addr %llx len %llu nr_pages %u\n",
+ args->vec.addr, args->vec.bytes, nr_pages);
+
+ /* XXX clamp nr_pages to limit the size of this alloc? */
+ pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
+ if (pages == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mr = kzalloc(sizeof(struct rds_mr), GFP_KERNEL);
+ if (mr == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ atomic_set(&mr->r_refcount, 1);
+ RB_CLEAR_NODE(&mr->r_rb_node);
+ mr->r_trans = rs->rs_transport;
+ mr->r_sock = rs;
+
+ if (args->flags & RDS_RDMA_USE_ONCE)
+ mr->r_use_once = 1;
+ if (args->flags & RDS_RDMA_INVALIDATE)
+ mr->r_invalidate = 1;
+ if (args->flags & RDS_RDMA_READWRITE)
+ mr->r_write = 1;
+
+ /*
+ * Pin the pages that make up the user buffer and transfer the page
+ * pointers to the mr's sg array. We check to see if we've mapped
+ * the whole region after transferring the partial page references
+ * to the sg array so that we can have one page ref cleanup path.
+ *
+ * For now we have no flag that tells us whether the mapping is
+ * r/o or r/w. We need to assume r/w, or we'll do a lot of RDMA to
+ * the zero page.
+ */
+ ret = rds_pin_pages(args->vec.addr & PAGE_MASK, nr_pages, pages, 1);
+ if (ret < 0)
+ goto out;
+
+ nents = ret;
+ sg = kcalloc(nents, sizeof(*sg), GFP_KERNEL);
+ if (sg == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ WARN_ON(!nents);
+ sg_init_table(sg, nents);
+
+ /* Stick all pages into the scatterlist */
+ for (i = 0 ; i < nents; i++)
+ sg_set_page(&sg[i], pages[i], PAGE_SIZE, 0);
+
+ rdsdebug("RDS: trans_private nents is %u\n", nents);
+
+ /* Obtain a transport specific MR. If this succeeds, the
+ * s/g list is now owned by the MR.
+ * Note that dma_map() implies that pending writes are
+ * flushed to RAM, so no dma_sync is needed here. */
+ trans_private = rs->rs_transport->get_mr(sg, nents, rs,
+ &mr->r_key);
+
+ if (IS_ERR(trans_private)) {
+ for (i = 0 ; i < nents; i++)
+ put_page(sg_page(&sg[i]));
+ kfree(sg);
+ ret = PTR_ERR(trans_private);
+ goto out;
+ }
+
+ mr->r_trans_private = trans_private;
+
+ rdsdebug("RDS: get_mr put_user key is %x cookie_addr %p\n",
+ mr->r_key, (void *)(unsigned long) args->cookie_addr);
+
+ /* The user may pass us an unaligned address, but we can only
+ * map page aligned regions. So we keep the offset, and build
+ * a 64bit cookie containing <R_Key, offset> and pass that
+ * around. */
+ cookie = rds_rdma_make_cookie(mr->r_key, args->vec.addr & ~PAGE_MASK);
+ if (cookie_ret)
+ *cookie_ret = cookie;
+
+ if (args->cookie_addr && put_user(cookie, (u64 __user *)(unsigned long) args->cookie_addr)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ /* Inserting the new MR into the rbtree bumps its
+ * reference count. */
+ spin_lock_irqsave(&rs->rs_rdma_lock, flags);
+ found = rds_mr_tree_walk(&rs->rs_rdma_keys, mr->r_key, mr);
+ spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
+
+ BUG_ON(found && found != mr);
+
+ rdsdebug("RDS: get_mr key is %x\n", mr->r_key);
+ if (mr_ret) {
+ atomic_inc(&mr->r_refcount);
+ *mr_ret = mr;
+ }
+
+ ret = 0;
+out:
+ kfree(pages);
+ if (mr)
+ rds_mr_put(mr);
+ return ret;
+}
+
+int rds_get_mr(struct rds_sock *rs, char __user *optval, int optlen)
+{
+ struct rds_get_mr_args args;
+
+ if (optlen != sizeof(struct rds_get_mr_args))
+ return -EINVAL;
+
+ if (copy_from_user(&args, (struct rds_get_mr_args __user *)optval,
+ sizeof(struct rds_get_mr_args)))
+ return -EFAULT;
+
+ return __rds_rdma_map(rs, &args, NULL, NULL);
+}
+
+/*
+ * Free the MR indicated by the given R_Key
+ */
+int rds_free_mr(struct rds_sock *rs, char __user *optval, int optlen)
+{
+ struct rds_free_mr_args args;
+ struct rds_mr *mr;
+ unsigned long flags;
+
+ if (optlen != sizeof(struct rds_free_mr_args))
+ return -EINVAL;
+
+ if (copy_from_user(&args, (struct rds_free_mr_args __user *)optval,
+ sizeof(struct rds_free_mr_args)))
+ return -EFAULT;
+
+ /* Special case - a null cookie means flush all unused MRs */
+ if (args.cookie == 0) {
+ if (!rs->rs_transport || !rs->rs_transport->flush_mrs)
+ return -EINVAL;
+ rs->rs_transport->flush_mrs();
+ return 0;
+ }
+
+ /* Look up the MR given its R_key and remove it from the rbtree
+ * so nobody else finds it.
+ * This should also prevent races with rds_rdma_unuse.
+ */
+ spin_lock_irqsave(&rs->rs_rdma_lock, flags);
+ mr = rds_mr_tree_walk(&rs->rs_rdma_keys, rds_rdma_cookie_key(args.cookie), NULL);
+ if (mr) {
+ rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
+ RB_CLEAR_NODE(&mr->r_rb_node);
+ if (args.flags & RDS_RDMA_INVALIDATE)
+ mr->r_invalidate = 1;
+ }
+ spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
+
+ if (!mr)
+ return -EINVAL;
+
+ /*
+ * call rds_destroy_mr() ourselves so that we're sure it's done by the time
+ * we return. If we let rds_mr_put() do it it might not happen until
+ * someone else drops their ref.
+ */
+ rds_destroy_mr(mr);
+ rds_mr_put(mr);
+ return 0;
+}
+
+/*
+ * 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)
+{
+ struct rds_mr *mr;
+ unsigned long flags;
+ int zot_me = 0;
+
+ spin_lock_irqsave(&rs->rs_rdma_lock, flags);
+ mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
+ if (mr && (mr->r_use_once || force)) {
+ rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
+ RB_CLEAR_NODE(&mr->r_rb_node);
+ zot_me = 1;
+ } else if (mr)
+ atomic_inc(&mr->r_refcount);
+ spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
+
+ /* May have to issue a dma_sync on this memory region.
+ * Note we could avoid this if the operation was a RDMA READ,
+ * but at this point we can't tell. */
+ if (mr != NULL) {
+ if (mr->r_trans->sync_mr)
+ mr->r_trans->sync_mr(mr->r_trans_private, DMA_FROM_DEVICE);
+
+ /* If the MR was marked as invalidate, this will
+ * trigger an async flush. */
+ if (zot_me)
+ rds_destroy_mr(mr);
+ rds_mr_put(mr);
+ }
+}
+
+void rds_rdma_free_op(struct rds_rdma_op *ro)
+{
+ unsigned int i;
+
+ for (i = 0; i < ro->r_nents; i++) {
+ struct page *page = sg_page(&ro->r_sg[i]);
+
+ /* Mark page dirty if it was possibly modified, which
+ * is the case for a RDMA_READ which copies from remote
+ * to local memory */
+ if (!ro->r_write)
+ set_page_dirty(page);
+ put_page(page);
+ }
+
+ kfree(ro->r_notifier);
+ kfree(ro);
+}
+
+/*
+ * args is a pointer to an in-kernel copy in the sendmsg cmsg.
+ */
+static struct rds_rdma_op *rds_rdma_prepare(struct rds_sock *rs,
+ struct rds_rdma_args *args)
+{
+ struct rds_iovec vec;
+ struct rds_rdma_op *op = NULL;
+ unsigned int nr_pages;
+ unsigned int max_pages;
+ unsigned int nr_bytes;
+ struct page **pages = NULL;
+ struct rds_iovec __user *local_vec;
+ struct scatterlist *sg;
+ unsigned int nr;
+ unsigned int i, j;
+ int ret;
+
+
+ if (rs->rs_bound_addr == 0) {
+ ret = -ENOTCONN; /* XXX not a great errno */
+ goto out;
+ }
+
+ if (args->nr_local > (u64)UINT_MAX) {
+ ret = -EMSGSIZE;
+ goto out;
+ }
+
+ nr_pages = 0;
+ max_pages = 0;
+
+ local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
+
+ /* figure out the number of pages in the vector */
+ for (i = 0; i < args->nr_local; i++) {
+ if (copy_from_user(&vec, &local_vec[i],
+ sizeof(struct rds_iovec))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ nr = rds_pages_in_vec(&vec);
+ if (nr == 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ max_pages = max(nr, max_pages);
+ nr_pages += nr;
+ }
+
+ pages = kcalloc(max_pages, sizeof(struct page *), GFP_KERNEL);
+ if (pages == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ op = kzalloc(offsetof(struct rds_rdma_op, r_sg[nr_pages]), GFP_KERNEL);
+ if (op == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ op->r_write = !!(args->flags & RDS_RDMA_READWRITE);
+ op->r_fence = !!(args->flags & RDS_RDMA_FENCE);
+ op->r_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
+ op->r_recverr = rs->rs_recverr;
+ WARN_ON(!nr_pages);
+ sg_init_table(op->r_sg, nr_pages);
+
+ if (op->r_notify || op->r_recverr) {
+ /* We allocate an uninitialized notifier here, because
+ * we don't want to do that in the completion handler. We
+ * would have to use GFP_ATOMIC there, and don't want to deal
+ * with failed allocations.
+ */
+ op->r_notifier = kmalloc(sizeof(struct rds_notifier), GFP_KERNEL);
+ if (!op->r_notifier) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ op->r_notifier->n_user_token = args->user_token;
+ op->r_notifier->n_status = RDS_RDMA_SUCCESS;
+ }
+
+ /* The cookie contains the R_Key of the remote memory region, and
+ * optionally an offset into it. This is how we implement RDMA into
+ * unaligned memory.
+ * When setting up the RDMA, we need to add that offset to the
+ * destination address (which is really an offset into the MR)
+ * FIXME: We may want to move this into ib_rdma.c
+ */
+ op->r_key = rds_rdma_cookie_key(args->cookie);
+ op->r_remote_addr = args->remote_vec.addr + rds_rdma_cookie_offset(args->cookie);
+
+ nr_bytes = 0;
+
+ rdsdebug("RDS: rdma prepare nr_local %llu rva %llx rkey %x\n",
+ (unsigned long long)args->nr_local,
+ (unsigned long long)args->remote_vec.addr,
+ op->r_key);
+
+ for (i = 0; i < args->nr_local; i++) {
+ if (copy_from_user(&vec, &local_vec[i],
+ sizeof(struct rds_iovec))) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ nr = rds_pages_in_vec(&vec);
+ if (nr == 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ rs->rs_user_addr = vec.addr;
+ rs->rs_user_bytes = vec.bytes;
+
+ /* did the user change the vec under us? */
+ if (nr > max_pages || op->r_nents + nr > nr_pages) {
+ ret = -EINVAL;
+ goto out;
+ }
+ /* If it's a WRITE operation, we want to pin the pages for reading.
+ * If it's a READ operation, we need to pin the pages for writing.
+ */
+ ret = rds_pin_pages(vec.addr & PAGE_MASK, nr, pages, !op->r_write);
+ if (ret < 0)
+ goto out;
+
+ rdsdebug("RDS: nr_bytes %u nr %u vec.bytes %llu vec.addr %llx\n",
+ nr_bytes, nr, vec.bytes, vec.addr);
+
+ nr_bytes += vec.bytes;
+
+ for (j = 0; j < nr; j++) {
+ unsigned int offset = vec.addr & ~PAGE_MASK;
+
+ sg = &op->r_sg[op->r_nents + j];
+ sg_set_page(sg, pages[j],
+ min_t(unsigned int, vec.bytes, PAGE_SIZE - offset),
+ offset);
+
+ rdsdebug("RDS: sg->offset %x sg->len %x vec.addr %llx vec.bytes %llu\n",
+ sg->offset, sg->length, vec.addr, vec.bytes);
+
+ vec.addr += sg->length;
+ vec.bytes -= sg->length;
+ }
+
+ op->r_nents += nr;
+ }
+
+
+ if (nr_bytes > args->remote_vec.bytes) {
+ rdsdebug("RDS nr_bytes %u remote_bytes %u do not match\n",
+ nr_bytes,
+ (unsigned int) args->remote_vec.bytes);
+ ret = -EINVAL;
+ goto out;
+ }
+ op->r_bytes = nr_bytes;
+
+ ret = 0;
+out:
+ kfree(pages);
+ if (ret) {
+ if (op)
+ rds_rdma_free_op(op);
+ op = ERR_PTR(ret);
+ }
+ return op;
+}
+
+/*
+ * 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_rdma_op *op;
+
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_rdma_args))
+ || rm->m_rdma_op != NULL)
+ return -EINVAL;
+
+ op = rds_rdma_prepare(rs, CMSG_DATA(cmsg));
+ if (IS_ERR(op))
+ return PTR_ERR(op);
+ rds_stats_inc(s_send_rdma);
+ rm->m_rdma_op = op;
+ return 0;
+}
+
+/*
+ * 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)
+{
+ unsigned long flags;
+ struct rds_mr *mr;
+ u32 r_key;
+ int err = 0;
+
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(rds_rdma_cookie_t))
+ || rm->m_rdma_cookie != 0)
+ return -EINVAL;
+
+ memcpy(&rm->m_rdma_cookie, CMSG_DATA(cmsg), sizeof(rm->m_rdma_cookie));
+
+ /* We are reusing a previously mapped MR here. Most likely, the
+ * application has written to the buffer, so we need to explicitly
+ * flush those writes to RAM. Otherwise the HCA may not see them
+ * when doing a DMA from that buffer.
+ */
+ r_key = rds_rdma_cookie_key(rm->m_rdma_cookie);
+
+ spin_lock_irqsave(&rs->rs_rdma_lock, flags);
+ mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
+ if (mr == NULL)
+ err = -EINVAL; /* invalid r_key */
+ else
+ atomic_inc(&mr->r_refcount);
+ spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
+
+ if (mr) {
+ mr->r_trans->sync_mr(mr->r_trans_private, DMA_TO_DEVICE);
+ rm->m_rdma_mr = mr;
+ }
+ return err;
+}
+
+/*
+ * 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)
+{
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_get_mr_args))
+ || rm->m_rdma_cookie != 0)
+ return -EINVAL;
+
+ return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie, &rm->m_rdma_mr);
+}
diff --git a/net/rds/rdma.h b/net/rds/rdma.h
new file mode 100644
index 0000000..4255120
--- /dev/null
+++ b/net/rds/rdma.h
@@ -0,0 +1,84 @@
+#ifndef _RDS_RDMA_H
+#define _RDS_RDMA_H
+
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/scatterlist.h>
+
+#include "rds.h"
+
+struct rds_mr {
+ struct rb_node r_rb_node;
+ atomic_t r_refcount;
+ u32 r_key;
+
+ /* A copy of the creation flags */
+ unsigned int r_use_once:1;
+ unsigned int r_invalidate:1;
+ unsigned int r_write:1;
+
+ /* This is for RDS_MR_DEAD.
+ * It would be nice & consistent to make this part of the above
+ * bit field here, but we need to use test_and_set_bit.
+ */
+ unsigned long r_state;
+ struct rds_sock *r_sock; /* back pointer to the socket that owns us */
+ struct rds_transport *r_trans;
+ void *r_trans_private;
+};
+
+/* Flags for mr->r_state */
+#define RDS_MR_DEAD 0
+
+struct rds_rdma_op {
+ u32 r_key;
+ u64 r_remote_addr;
+ unsigned int r_write:1;
+ unsigned int r_fence:1;
+ unsigned int r_notify:1;
+ unsigned int r_recverr:1;
+ unsigned int r_mapped:1;
+ struct rds_notifier *r_notifier;
+ unsigned int r_bytes;
+ unsigned int r_nents;
+ unsigned int r_count;
+ struct scatterlist r_sg[0];
+};
+
+static inline rds_rdma_cookie_t rds_rdma_make_cookie(u32 r_key, u32 offset)
+{
+ return r_key | (((u64) offset) << 32);
+}
+
+static inline u32 rds_rdma_cookie_key(rds_rdma_cookie_t cookie)
+{
+ return cookie;
+}
+
+static inline u32 rds_rdma_cookie_offset(rds_rdma_cookie_t cookie)
+{
+ return cookie >> 32;
+}
+
+int rds_get_mr(struct rds_sock *rs, char __user *optval, int optlen);
+int rds_free_mr(struct rds_sock *rs, char __user *optval, int optlen);
+void rds_rdma_drop_keys(struct rds_sock *rs);
+int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+void rds_rdma_free_op(struct rds_rdma_op *ro);
+void rds_rdma_send_complete(struct rds_message *rm, int);
+
+extern void __rds_put_mr_final(struct rds_mr *mr);
+static inline void rds_mr_put(struct rds_mr *mr)
+{
+ if (atomic_dec_and_test(&mr->r_refcount))
+ __rds_put_mr_final(mr);
+}
+
+#endif
--
1.5.6.3
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