From eff5f53bef75c0864a5da06bb688939092b848dc Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Tue, 24 Feb 2009 15:30:29 +0000 Subject: RDS: RDMA support 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 Signed-off-by: David S. Miller --- net/rds/rdma.c | 679 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 679 insertions(+) create mode 100644 net/rds/rdma.c (limited to 'net/rds/rdma.c') diff --git a/net/rds/rdma.c b/net/rds/rdma.c new file mode 100644 index 000000000000..eaeeb91e1119 --- /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 +#include +#include /* 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 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 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); +} -- cgit