2 * Copyright (c) 2007 Oracle. All rights reserved.
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
33 #include <linux/pagemap.h>
34 #include <linux/slab.h>
35 #include <linux/rbtree.h>
36 #include <linux/dma-mapping.h> /* for DMA_*_DEVICE */
43 * - should we limit the size of a mr region? let transport return failure?
44 * - should we detect duplicate keys on a socket? hmm.
45 * - an rdma is an mlock, apply rlimit?
49 * get the number of pages by looking at the page indices that the start and
50 * end addresses fall in.
52 * Returns 0 if the vec is invalid. It is invalid if the number of bytes
53 * causes the address to wrap or overflows an unsigned int. This comes
54 * from being stored in the 'length' member of 'struct scatterlist'.
56 static unsigned int rds_pages_in_vec(struct rds_iovec
*vec
)
58 if ((vec
->addr
+ vec
->bytes
<= vec
->addr
) ||
59 (vec
->bytes
> (u64
)UINT_MAX
))
62 return ((vec
->addr
+ vec
->bytes
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
) -
63 (vec
->addr
>> PAGE_SHIFT
);
66 static struct rds_mr
*rds_mr_tree_walk(struct rb_root
*root
, u64 key
,
67 struct rds_mr
*insert
)
69 struct rb_node
**p
= &root
->rb_node
;
70 struct rb_node
*parent
= NULL
;
75 mr
= rb_entry(parent
, struct rds_mr
, r_rb_node
);
79 else if (key
> mr
->r_key
)
86 rb_link_node(&insert
->r_rb_node
, parent
, p
);
87 rb_insert_color(&insert
->r_rb_node
, root
);
88 atomic_inc(&insert
->r_refcount
);
94 * Destroy the transport-specific part of a MR.
96 static void rds_destroy_mr(struct rds_mr
*mr
)
98 struct rds_sock
*rs
= mr
->r_sock
;
99 void *trans_private
= NULL
;
102 rdsdebug("RDS: destroy mr key is %x refcnt %u\n",
103 mr
->r_key
, atomic_read(&mr
->r_refcount
));
105 if (test_and_set_bit(RDS_MR_DEAD
, &mr
->r_state
))
108 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
109 if (!RB_EMPTY_NODE(&mr
->r_rb_node
))
110 rb_erase(&mr
->r_rb_node
, &rs
->rs_rdma_keys
);
111 trans_private
= mr
->r_trans_private
;
112 mr
->r_trans_private
= NULL
;
113 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
116 mr
->r_trans
->free_mr(trans_private
, mr
->r_invalidate
);
119 void __rds_put_mr_final(struct rds_mr
*mr
)
126 * By the time this is called we can't have any more ioctls called on
127 * the socket so we don't need to worry about racing with others.
129 void rds_rdma_drop_keys(struct rds_sock
*rs
)
132 struct rb_node
*node
;
135 /* Release any MRs associated with this socket */
136 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
137 while ((node
= rb_first(&rs
->rs_rdma_keys
))) {
138 mr
= container_of(node
, struct rds_mr
, r_rb_node
);
139 if (mr
->r_trans
== rs
->rs_transport
)
140 mr
->r_invalidate
= 0;
141 rb_erase(&mr
->r_rb_node
, &rs
->rs_rdma_keys
);
142 RB_CLEAR_NODE(&mr
->r_rb_node
);
143 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
146 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
148 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
150 if (rs
->rs_transport
&& rs
->rs_transport
->flush_mrs
)
151 rs
->rs_transport
->flush_mrs();
155 * Helper function to pin user pages.
157 static int rds_pin_pages(unsigned long user_addr
, unsigned int nr_pages
,
158 struct page
**pages
, int write
)
162 ret
= get_user_pages_fast(user_addr
, nr_pages
, write
, pages
);
164 if (ret
>= 0 && ret
< nr_pages
) {
166 put_page(pages
[ret
]);
173 static int __rds_rdma_map(struct rds_sock
*rs
, struct rds_get_mr_args
*args
,
174 u64
*cookie_ret
, struct rds_mr
**mr_ret
)
176 struct rds_mr
*mr
= NULL
, *found
;
177 unsigned int nr_pages
;
178 struct page
**pages
= NULL
;
179 struct scatterlist
*sg
;
182 rds_rdma_cookie_t cookie
;
187 if (rs
->rs_bound_addr
== 0) {
188 ret
= -ENOTCONN
; /* XXX not a great errno */
192 if (!rs
->rs_transport
->get_mr
) {
197 nr_pages
= rds_pages_in_vec(&args
->vec
);
203 rdsdebug("RDS: get_mr addr %llx len %llu nr_pages %u\n",
204 args
->vec
.addr
, args
->vec
.bytes
, nr_pages
);
206 /* XXX clamp nr_pages to limit the size of this alloc? */
207 pages
= kcalloc(nr_pages
, sizeof(struct page
*), GFP_KERNEL
);
213 mr
= kzalloc(sizeof(struct rds_mr
), GFP_KERNEL
);
219 atomic_set(&mr
->r_refcount
, 1);
220 RB_CLEAR_NODE(&mr
->r_rb_node
);
221 mr
->r_trans
= rs
->rs_transport
;
224 if (args
->flags
& RDS_RDMA_USE_ONCE
)
226 if (args
->flags
& RDS_RDMA_INVALIDATE
)
227 mr
->r_invalidate
= 1;
228 if (args
->flags
& RDS_RDMA_READWRITE
)
232 * Pin the pages that make up the user buffer and transfer the page
233 * pointers to the mr's sg array. We check to see if we've mapped
234 * the whole region after transferring the partial page references
235 * to the sg array so that we can have one page ref cleanup path.
237 * For now we have no flag that tells us whether the mapping is
238 * r/o or r/w. We need to assume r/w, or we'll do a lot of RDMA to
241 ret
= rds_pin_pages(args
->vec
.addr
& PAGE_MASK
, nr_pages
, pages
, 1);
246 sg
= kcalloc(nents
, sizeof(*sg
), GFP_KERNEL
);
252 sg_init_table(sg
, nents
);
254 /* Stick all pages into the scatterlist */
255 for (i
= 0 ; i
< nents
; i
++)
256 sg_set_page(&sg
[i
], pages
[i
], PAGE_SIZE
, 0);
258 rdsdebug("RDS: trans_private nents is %u\n", nents
);
260 /* Obtain a transport specific MR. If this succeeds, the
261 * s/g list is now owned by the MR.
262 * Note that dma_map() implies that pending writes are
263 * flushed to RAM, so no dma_sync is needed here. */
264 trans_private
= rs
->rs_transport
->get_mr(sg
, nents
, rs
,
267 if (IS_ERR(trans_private
)) {
268 for (i
= 0 ; i
< nents
; i
++)
269 put_page(sg_page(&sg
[i
]));
271 ret
= PTR_ERR(trans_private
);
275 mr
->r_trans_private
= trans_private
;
277 rdsdebug("RDS: get_mr put_user key is %x cookie_addr %p\n",
278 mr
->r_key
, (void *)(unsigned long) args
->cookie_addr
);
280 /* The user may pass us an unaligned address, but we can only
281 * map page aligned regions. So we keep the offset, and build
282 * a 64bit cookie containing <R_Key, offset> and pass that
284 cookie
= rds_rdma_make_cookie(mr
->r_key
, args
->vec
.addr
& ~PAGE_MASK
);
286 *cookie_ret
= cookie
;
288 if (args
->cookie_addr
&& put_user(cookie
, (u64 __user
*)(unsigned long) args
->cookie_addr
)) {
293 /* Inserting the new MR into the rbtree bumps its
294 * reference count. */
295 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
296 found
= rds_mr_tree_walk(&rs
->rs_rdma_keys
, mr
->r_key
, mr
);
297 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
299 BUG_ON(found
&& found
!= mr
);
301 rdsdebug("RDS: get_mr key is %x\n", mr
->r_key
);
303 atomic_inc(&mr
->r_refcount
);
315 int rds_get_mr(struct rds_sock
*rs
, char __user
*optval
, int optlen
)
317 struct rds_get_mr_args args
;
319 if (optlen
!= sizeof(struct rds_get_mr_args
))
322 if (copy_from_user(&args
, (struct rds_get_mr_args __user
*)optval
,
323 sizeof(struct rds_get_mr_args
)))
326 return __rds_rdma_map(rs
, &args
, NULL
, NULL
);
329 int rds_get_mr_for_dest(struct rds_sock
*rs
, char __user
*optval
, int optlen
)
331 struct rds_get_mr_for_dest_args args
;
332 struct rds_get_mr_args new_args
;
334 if (optlen
!= sizeof(struct rds_get_mr_for_dest_args
))
337 if (copy_from_user(&args
, (struct rds_get_mr_for_dest_args __user
*)optval
,
338 sizeof(struct rds_get_mr_for_dest_args
)))
342 * Initially, just behave like get_mr().
343 * TODO: Implement get_mr as wrapper around this
346 new_args
.vec
= args
.vec
;
347 new_args
.cookie_addr
= args
.cookie_addr
;
348 new_args
.flags
= args
.flags
;
350 return __rds_rdma_map(rs
, &new_args
, NULL
, NULL
);
354 * Free the MR indicated by the given R_Key
356 int rds_free_mr(struct rds_sock
*rs
, char __user
*optval
, int optlen
)
358 struct rds_free_mr_args args
;
362 if (optlen
!= sizeof(struct rds_free_mr_args
))
365 if (copy_from_user(&args
, (struct rds_free_mr_args __user
*)optval
,
366 sizeof(struct rds_free_mr_args
)))
369 /* Special case - a null cookie means flush all unused MRs */
370 if (args
.cookie
== 0) {
371 if (!rs
->rs_transport
|| !rs
->rs_transport
->flush_mrs
)
373 rs
->rs_transport
->flush_mrs();
377 /* Look up the MR given its R_key and remove it from the rbtree
378 * so nobody else finds it.
379 * This should also prevent races with rds_rdma_unuse.
381 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
382 mr
= rds_mr_tree_walk(&rs
->rs_rdma_keys
, rds_rdma_cookie_key(args
.cookie
), NULL
);
384 rb_erase(&mr
->r_rb_node
, &rs
->rs_rdma_keys
);
385 RB_CLEAR_NODE(&mr
->r_rb_node
);
386 if (args
.flags
& RDS_RDMA_INVALIDATE
)
387 mr
->r_invalidate
= 1;
389 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
395 * call rds_destroy_mr() ourselves so that we're sure it's done by the time
396 * we return. If we let rds_mr_put() do it it might not happen until
397 * someone else drops their ref.
405 * This is called when we receive an extension header that
406 * tells us this MR was used. It allows us to implement
409 void rds_rdma_unuse(struct rds_sock
*rs
, u32 r_key
, int force
)
415 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
416 mr
= rds_mr_tree_walk(&rs
->rs_rdma_keys
, r_key
, NULL
);
417 if (mr
&& (mr
->r_use_once
|| force
)) {
418 rb_erase(&mr
->r_rb_node
, &rs
->rs_rdma_keys
);
419 RB_CLEAR_NODE(&mr
->r_rb_node
);
422 atomic_inc(&mr
->r_refcount
);
423 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
425 /* May have to issue a dma_sync on this memory region.
426 * Note we could avoid this if the operation was a RDMA READ,
427 * but at this point we can't tell. */
429 if (mr
->r_trans
->sync_mr
)
430 mr
->r_trans
->sync_mr(mr
->r_trans_private
, DMA_FROM_DEVICE
);
432 /* If the MR was marked as invalidate, this will
433 * trigger an async flush. */
440 void rds_rdma_free_op(struct rds_rdma_op
*ro
)
444 for (i
= 0; i
< ro
->r_nents
; i
++) {
445 struct page
*page
= sg_page(&ro
->r_sg
[i
]);
447 /* Mark page dirty if it was possibly modified, which
448 * is the case for a RDMA_READ which copies from remote
451 BUG_ON(irqs_disabled());
452 set_page_dirty(page
);
457 kfree(ro
->r_notifier
);
462 * args is a pointer to an in-kernel copy in the sendmsg cmsg.
464 static struct rds_rdma_op
*rds_rdma_prepare(struct rds_sock
*rs
,
465 struct rds_rdma_args
*args
)
467 struct rds_iovec vec
;
468 struct rds_rdma_op
*op
= NULL
;
469 unsigned int nr_pages
;
470 unsigned int max_pages
;
471 unsigned int nr_bytes
;
472 struct page
**pages
= NULL
;
473 struct rds_iovec __user
*local_vec
;
474 struct scatterlist
*sg
;
480 if (rs
->rs_bound_addr
== 0) {
481 ret
= -ENOTCONN
; /* XXX not a great errno */
485 if (args
->nr_local
> (u64
)UINT_MAX
) {
493 local_vec
= (struct rds_iovec __user
*)(unsigned long) args
->local_vec_addr
;
495 /* figure out the number of pages in the vector */
496 for (i
= 0; i
< args
->nr_local
; i
++) {
497 if (copy_from_user(&vec
, &local_vec
[i
],
498 sizeof(struct rds_iovec
))) {
503 nr
= rds_pages_in_vec(&vec
);
509 max_pages
= max(nr
, max_pages
);
513 pages
= kcalloc(max_pages
, sizeof(struct page
*), GFP_KERNEL
);
519 op
= kzalloc(offsetof(struct rds_rdma_op
, r_sg
[nr_pages
]), GFP_KERNEL
);
525 op
->r_write
= !!(args
->flags
& RDS_RDMA_READWRITE
);
526 op
->r_fence
= !!(args
->flags
& RDS_RDMA_FENCE
);
527 op
->r_notify
= !!(args
->flags
& RDS_RDMA_NOTIFY_ME
);
528 op
->r_recverr
= rs
->rs_recverr
;
530 sg_init_table(op
->r_sg
, nr_pages
);
532 if (op
->r_notify
|| op
->r_recverr
) {
533 /* We allocate an uninitialized notifier here, because
534 * we don't want to do that in the completion handler. We
535 * would have to use GFP_ATOMIC there, and don't want to deal
536 * with failed allocations.
538 op
->r_notifier
= kmalloc(sizeof(struct rds_notifier
), GFP_KERNEL
);
539 if (!op
->r_notifier
) {
543 op
->r_notifier
->n_user_token
= args
->user_token
;
544 op
->r_notifier
->n_status
= RDS_RDMA_SUCCESS
;
547 /* The cookie contains the R_Key of the remote memory region, and
548 * optionally an offset into it. This is how we implement RDMA into
550 * When setting up the RDMA, we need to add that offset to the
551 * destination address (which is really an offset into the MR)
552 * FIXME: We may want to move this into ib_rdma.c
554 op
->r_key
= rds_rdma_cookie_key(args
->cookie
);
555 op
->r_remote_addr
= args
->remote_vec
.addr
+ rds_rdma_cookie_offset(args
->cookie
);
559 rdsdebug("RDS: rdma prepare nr_local %llu rva %llx rkey %x\n",
560 (unsigned long long)args
->nr_local
,
561 (unsigned long long)args
->remote_vec
.addr
,
564 for (i
= 0; i
< args
->nr_local
; i
++) {
565 if (copy_from_user(&vec
, &local_vec
[i
],
566 sizeof(struct rds_iovec
))) {
571 nr
= rds_pages_in_vec(&vec
);
577 rs
->rs_user_addr
= vec
.addr
;
578 rs
->rs_user_bytes
= vec
.bytes
;
580 /* did the user change the vec under us? */
581 if (nr
> max_pages
|| op
->r_nents
+ nr
> nr_pages
) {
585 /* If it's a WRITE operation, we want to pin the pages for reading.
586 * If it's a READ operation, we need to pin the pages for writing.
588 ret
= rds_pin_pages(vec
.addr
& PAGE_MASK
, nr
, pages
, !op
->r_write
);
592 rdsdebug("RDS: nr_bytes %u nr %u vec.bytes %llu vec.addr %llx\n",
593 nr_bytes
, nr
, vec
.bytes
, vec
.addr
);
595 nr_bytes
+= vec
.bytes
;
597 for (j
= 0; j
< nr
; j
++) {
598 unsigned int offset
= vec
.addr
& ~PAGE_MASK
;
600 sg
= &op
->r_sg
[op
->r_nents
+ j
];
601 sg_set_page(sg
, pages
[j
],
602 min_t(unsigned int, vec
.bytes
, PAGE_SIZE
- offset
),
605 rdsdebug("RDS: sg->offset %x sg->len %x vec.addr %llx vec.bytes %llu\n",
606 sg
->offset
, sg
->length
, vec
.addr
, vec
.bytes
);
608 vec
.addr
+= sg
->length
;
609 vec
.bytes
-= sg
->length
;
616 if (nr_bytes
> args
->remote_vec
.bytes
) {
617 rdsdebug("RDS nr_bytes %u remote_bytes %u do not match\n",
619 (unsigned int) args
->remote_vec
.bytes
);
623 op
->r_bytes
= nr_bytes
;
630 rds_rdma_free_op(op
);
637 * The application asks for a RDMA transfer.
638 * Extract all arguments and set up the rdma_op
640 int rds_cmsg_rdma_args(struct rds_sock
*rs
, struct rds_message
*rm
,
641 struct cmsghdr
*cmsg
)
643 struct rds_rdma_op
*op
;
645 if (cmsg
->cmsg_len
< CMSG_LEN(sizeof(struct rds_rdma_args
)) ||
649 op
= rds_rdma_prepare(rs
, CMSG_DATA(cmsg
));
652 rds_stats_inc(s_send_rdma
);
658 * The application wants us to pass an RDMA destination (aka MR)
661 int rds_cmsg_rdma_dest(struct rds_sock
*rs
, struct rds_message
*rm
,
662 struct cmsghdr
*cmsg
)
669 if (cmsg
->cmsg_len
< CMSG_LEN(sizeof(rds_rdma_cookie_t
)) ||
670 rm
->m_rdma_cookie
!= 0)
673 memcpy(&rm
->m_rdma_cookie
, CMSG_DATA(cmsg
), sizeof(rm
->m_rdma_cookie
));
675 /* We are reusing a previously mapped MR here. Most likely, the
676 * application has written to the buffer, so we need to explicitly
677 * flush those writes to RAM. Otherwise the HCA may not see them
678 * when doing a DMA from that buffer.
680 r_key
= rds_rdma_cookie_key(rm
->m_rdma_cookie
);
682 spin_lock_irqsave(&rs
->rs_rdma_lock
, flags
);
683 mr
= rds_mr_tree_walk(&rs
->rs_rdma_keys
, r_key
, NULL
);
685 err
= -EINVAL
; /* invalid r_key */
687 atomic_inc(&mr
->r_refcount
);
688 spin_unlock_irqrestore(&rs
->rs_rdma_lock
, flags
);
691 mr
->r_trans
->sync_mr(mr
->r_trans_private
, DMA_TO_DEVICE
);
698 * The application passes us an address range it wants to enable RDMA
699 * to/from. We map the area, and save the <R_Key,offset> pair
700 * in rm->m_rdma_cookie. This causes it to be sent along to the peer
701 * in an extension header.
703 int rds_cmsg_rdma_map(struct rds_sock
*rs
, struct rds_message
*rm
,
704 struct cmsghdr
*cmsg
)
706 if (cmsg
->cmsg_len
< CMSG_LEN(sizeof(struct rds_get_mr_args
)) ||
707 rm
->m_rdma_cookie
!= 0)
710 return __rds_rdma_map(rs
, CMSG_DATA(cmsg
), &rm
->m_rdma_cookie
, &rm
->m_rdma_mr
);