/*
* 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);
}
