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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 detect duplicate keys on a socket? hmm.
44 * - an rdma is an mlock, apply rlimit?
48 * get the number of pages by looking at the page indices that the start and
49 * end addresses fall in.
51 * Returns 0 if the vec is invalid. It is invalid if the number of bytes
52 * causes the address to wrap or overflows an unsigned int. This comes
53 * from being stored in the 'length' member of 'struct scatterlist'.
55 static unsigned int rds_pages_in_vec(struct rds_iovec *vec)
57 if ((vec->addr + vec->bytes <= vec->addr) ||
58 (vec->bytes > (u64)UINT_MAX))
61 return ((vec->addr + vec->bytes + PAGE_SIZE - 1) >> PAGE_SHIFT) -
62 (vec->addr >> PAGE_SHIFT);
65 static struct rds_mr *rds_mr_tree_walk(struct rb_root *root, u64 key,
66 struct rds_mr *insert)
68 struct rb_node **p = &root->rb_node;
69 struct rb_node *parent = NULL;
74 mr = rb_entry(parent, struct rds_mr, r_rb_node);
78 else if (key > mr->r_key)
85 rb_link_node(&insert->r_rb_node, parent, p);
86 rb_insert_color(&insert->r_rb_node, root);
87 refcount_inc(&insert->r_refcount);
93 * Destroy the transport-specific part of a MR.
95 static void rds_destroy_mr(struct rds_mr *mr)
97 struct rds_sock *rs = mr->r_sock;
98 void *trans_private = NULL;
101 rdsdebug("RDS: destroy mr key is %x refcnt %u\n",
102 mr->r_key, refcount_read(&mr->r_refcount));
104 if (test_and_set_bit(RDS_MR_DEAD, &mr->r_state))
107 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
108 if (!RB_EMPTY_NODE(&mr->r_rb_node))
109 rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
110 trans_private = mr->r_trans_private;
111 mr->r_trans_private = NULL;
112 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
115 mr->r_trans->free_mr(trans_private, mr->r_invalidate);
118 void __rds_put_mr_final(struct rds_mr *mr)
125 * By the time this is called we can't have any more ioctls called on
126 * the socket so we don't need to worry about racing with others.
128 void rds_rdma_drop_keys(struct rds_sock *rs)
131 struct rb_node *node;
134 /* Release any MRs associated with this socket */
135 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
136 while ((node = rb_first(&rs->rs_rdma_keys))) {
137 mr = rb_entry(node, struct rds_mr, r_rb_node);
138 if (mr->r_trans == rs->rs_transport)
139 mr->r_invalidate = 0;
140 rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
141 RB_CLEAR_NODE(&mr->r_rb_node);
142 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
145 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
147 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
149 if (rs->rs_transport && rs->rs_transport->flush_mrs)
150 rs->rs_transport->flush_mrs();
154 * Helper function to pin user pages.
156 static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages,
157 struct page **pages, int write)
161 ret = get_user_pages_fast(user_addr, nr_pages, write ? FOLL_WRITE : 0,
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,
175 struct rds_conn_path *cp)
177 struct rds_mr *mr = NULL, *found;
178 unsigned int nr_pages;
179 struct page **pages = NULL;
180 struct scatterlist *sg;
183 rds_rdma_cookie_t cookie;
188 if (ipv6_addr_any(&rs->rs_bound_addr) || !rs->rs_transport) {
189 ret = -ENOTCONN; /* XXX not a great errno */
193 if (!rs->rs_transport->get_mr) {
198 nr_pages = rds_pages_in_vec(&args->vec);
204 /* Restrict the size of mr irrespective of underlying transport
205 * To account for unaligned mr regions, subtract one from nr_pages
207 if ((nr_pages - 1) > (RDS_MAX_MSG_SIZE >> PAGE_SHIFT)) {
212 rdsdebug("RDS: get_mr addr %llx len %llu nr_pages %u\n",
213 args->vec.addr, args->vec.bytes, nr_pages);
215 /* XXX clamp nr_pages to limit the size of this alloc? */
216 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
222 mr = kzalloc(sizeof(struct rds_mr), GFP_KERNEL);
228 refcount_set(&mr->r_refcount, 1);
229 RB_CLEAR_NODE(&mr->r_rb_node);
230 mr->r_trans = rs->rs_transport;
233 if (args->flags & RDS_RDMA_USE_ONCE)
235 if (args->flags & RDS_RDMA_INVALIDATE)
236 mr->r_invalidate = 1;
237 if (args->flags & RDS_RDMA_READWRITE)
241 * Pin the pages that make up the user buffer and transfer the page
242 * pointers to the mr's sg array. We check to see if we've mapped
243 * the whole region after transferring the partial page references
244 * to the sg array so that we can have one page ref cleanup path.
246 * For now we have no flag that tells us whether the mapping is
247 * r/o or r/w. We need to assume r/w, or we'll do a lot of RDMA to
250 ret = rds_pin_pages(args->vec.addr, nr_pages, pages, 1);
255 sg = kcalloc(nents, sizeof(*sg), GFP_KERNEL);
261 sg_init_table(sg, nents);
263 /* Stick all pages into the scatterlist */
264 for (i = 0 ; i < nents; i++)
265 sg_set_page(&sg[i], pages[i], PAGE_SIZE, 0);
267 rdsdebug("RDS: trans_private nents is %u\n", nents);
269 /* Obtain a transport specific MR. If this succeeds, the
270 * s/g list is now owned by the MR.
271 * Note that dma_map() implies that pending writes are
272 * flushed to RAM, so no dma_sync is needed here. */
273 trans_private = rs->rs_transport->get_mr(sg, nents, rs,
275 cp ? cp->cp_conn : NULL);
277 if (IS_ERR(trans_private)) {
278 for (i = 0 ; i < nents; i++)
279 put_page(sg_page(&sg[i]));
281 ret = PTR_ERR(trans_private);
285 mr->r_trans_private = trans_private;
287 rdsdebug("RDS: get_mr put_user key is %x cookie_addr %p\n",
288 mr->r_key, (void *)(unsigned long) args->cookie_addr);
290 /* The user may pass us an unaligned address, but we can only
291 * map page aligned regions. So we keep the offset, and build
292 * a 64bit cookie containing <R_Key, offset> and pass that
294 cookie = rds_rdma_make_cookie(mr->r_key, args->vec.addr & ~PAGE_MASK);
296 *cookie_ret = cookie;
298 if (args->cookie_addr && put_user(cookie, (u64 __user *)(unsigned long) args->cookie_addr)) {
303 /* Inserting the new MR into the rbtree bumps its
304 * reference count. */
305 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
306 found = rds_mr_tree_walk(&rs->rs_rdma_keys, mr->r_key, mr);
307 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
309 BUG_ON(found && found != mr);
311 rdsdebug("RDS: get_mr key is %x\n", mr->r_key);
313 refcount_inc(&mr->r_refcount);
325 int rds_get_mr(struct rds_sock *rs, char __user *optval, int optlen)
327 struct rds_get_mr_args args;
329 if (optlen != sizeof(struct rds_get_mr_args))
332 if (copy_from_user(&args, (struct rds_get_mr_args __user *)optval,
333 sizeof(struct rds_get_mr_args)))
336 return __rds_rdma_map(rs, &args, NULL, NULL, NULL);
339 int rds_get_mr_for_dest(struct rds_sock *rs, char __user *optval, int optlen)
341 struct rds_get_mr_for_dest_args args;
342 struct rds_get_mr_args new_args;
344 if (optlen != sizeof(struct rds_get_mr_for_dest_args))
347 if (copy_from_user(&args, (struct rds_get_mr_for_dest_args __user *)optval,
348 sizeof(struct rds_get_mr_for_dest_args)))
352 * Initially, just behave like get_mr().
353 * TODO: Implement get_mr as wrapper around this
356 new_args.vec = args.vec;
357 new_args.cookie_addr = args.cookie_addr;
358 new_args.flags = args.flags;
360 return __rds_rdma_map(rs, &new_args, NULL, NULL, NULL);
364 * Free the MR indicated by the given R_Key
366 int rds_free_mr(struct rds_sock *rs, char __user *optval, int optlen)
368 struct rds_free_mr_args args;
372 if (optlen != sizeof(struct rds_free_mr_args))
375 if (copy_from_user(&args, (struct rds_free_mr_args __user *)optval,
376 sizeof(struct rds_free_mr_args)))
379 /* Special case - a null cookie means flush all unused MRs */
380 if (args.cookie == 0) {
381 if (!rs->rs_transport || !rs->rs_transport->flush_mrs)
383 rs->rs_transport->flush_mrs();
387 /* Look up the MR given its R_key and remove it from the rbtree
388 * so nobody else finds it.
389 * This should also prevent races with rds_rdma_unuse.
391 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
392 mr = rds_mr_tree_walk(&rs->rs_rdma_keys, rds_rdma_cookie_key(args.cookie), NULL);
394 rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
395 RB_CLEAR_NODE(&mr->r_rb_node);
396 if (args.flags & RDS_RDMA_INVALIDATE)
397 mr->r_invalidate = 1;
399 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
405 * call rds_destroy_mr() ourselves so that we're sure it's done by the time
406 * we return. If we let rds_mr_put() do it it might not happen until
407 * someone else drops their ref.
415 * This is called when we receive an extension header that
416 * tells us this MR was used. It allows us to implement
419 void rds_rdma_unuse(struct rds_sock *rs, u32 r_key, int force)
425 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
426 mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
428 pr_debug("rds: trying to unuse MR with unknown r_key %u!\n",
430 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
434 if (mr->r_use_once || force) {
435 rb_erase(&mr->r_rb_node, &rs->rs_rdma_keys);
436 RB_CLEAR_NODE(&mr->r_rb_node);
439 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
441 /* May have to issue a dma_sync on this memory region.
442 * Note we could avoid this if the operation was a RDMA READ,
443 * but at this point we can't tell. */
444 if (mr->r_trans->sync_mr)
445 mr->r_trans->sync_mr(mr->r_trans_private, DMA_FROM_DEVICE);
447 /* If the MR was marked as invalidate, this will
448 * trigger an async flush. */
455 void rds_rdma_free_op(struct rm_rdma_op *ro)
459 for (i = 0; i < ro->op_nents; i++) {
460 struct page *page = sg_page(&ro->op_sg[i]);
462 /* Mark page dirty if it was possibly modified, which
463 * is the case for a RDMA_READ which copies from remote
466 WARN_ON(!page->mapping && irqs_disabled());
467 set_page_dirty(page);
472 kfree(ro->op_notifier);
473 ro->op_notifier = NULL;
477 void rds_atomic_free_op(struct rm_atomic_op *ao)
479 struct page *page = sg_page(ao->op_sg);
481 /* Mark page dirty if it was possibly modified, which
482 * is the case for a RDMA_READ which copies from remote
484 set_page_dirty(page);
487 kfree(ao->op_notifier);
488 ao->op_notifier = NULL;
494 * Count the number of pages needed to describe an incoming iovec array.
496 static int rds_rdma_pages(struct rds_iovec iov[], int nr_iovecs)
499 unsigned int nr_pages;
502 /* figure out the number of pages in the vector */
503 for (i = 0; i < nr_iovecs; i++) {
504 nr_pages = rds_pages_in_vec(&iov[i]);
508 tot_pages += nr_pages;
511 * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
512 * so tot_pages cannot overflow without first going negative.
521 int rds_rdma_extra_size(struct rds_rdma_args *args,
522 struct rds_iov_vector *iov)
524 struct rds_iovec *vec;
525 struct rds_iovec __user *local_vec;
527 unsigned int nr_pages;
530 local_vec = (struct rds_iovec __user *)(unsigned long) args->local_vec_addr;
532 if (args->nr_local == 0)
535 iov->iov = kcalloc(args->nr_local,
536 sizeof(struct rds_iovec),
543 if (copy_from_user(vec, local_vec, args->nr_local *
544 sizeof(struct rds_iovec)))
546 iov->len = args->nr_local;
548 /* figure out the number of pages in the vector */
549 for (i = 0; i < args->nr_local; i++, vec++) {
551 nr_pages = rds_pages_in_vec(vec);
555 tot_pages += nr_pages;
558 * nr_pages for one entry is limited to (UINT_MAX>>PAGE_SHIFT)+1,
559 * so tot_pages cannot overflow without first going negative.
565 return tot_pages * sizeof(struct scatterlist);
569 * The application asks for a RDMA transfer.
570 * Extract all arguments and set up the rdma_op
572 int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
573 struct cmsghdr *cmsg,
574 struct rds_iov_vector *vec)
576 struct rds_rdma_args *args;
577 struct rm_rdma_op *op = &rm->rdma;
579 unsigned int nr_bytes;
580 struct page **pages = NULL;
581 struct rds_iovec *iovs;
585 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_rdma_args))
586 || rm->rdma.op_active)
589 args = CMSG_DATA(cmsg);
591 if (ipv6_addr_any(&rs->rs_bound_addr)) {
592 ret = -ENOTCONN; /* XXX not a great errno */
596 if (args->nr_local > UIO_MAXIOV) {
601 if (vec->len != args->nr_local) {
608 nr_pages = rds_rdma_pages(iovs, args->nr_local);
614 pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
620 op->op_write = !!(args->flags & RDS_RDMA_READWRITE);
621 op->op_fence = !!(args->flags & RDS_RDMA_FENCE);
622 op->op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
623 op->op_silent = !!(args->flags & RDS_RDMA_SILENT);
625 op->op_recverr = rs->rs_recverr;
627 op->op_sg = rds_message_alloc_sgs(rm, nr_pages, &ret);
631 if (op->op_notify || op->op_recverr) {
632 /* We allocate an uninitialized notifier here, because
633 * we don't want to do that in the completion handler. We
634 * would have to use GFP_ATOMIC there, and don't want to deal
635 * with failed allocations.
637 op->op_notifier = kmalloc(sizeof(struct rds_notifier), GFP_KERNEL);
638 if (!op->op_notifier) {
642 op->op_notifier->n_user_token = args->user_token;
643 op->op_notifier->n_status = RDS_RDMA_SUCCESS;
646 /* The cookie contains the R_Key of the remote memory region, and
647 * optionally an offset into it. This is how we implement RDMA into
649 * When setting up the RDMA, we need to add that offset to the
650 * destination address (which is really an offset into the MR)
651 * FIXME: We may want to move this into ib_rdma.c
653 op->op_rkey = rds_rdma_cookie_key(args->cookie);
654 op->op_remote_addr = args->remote_vec.addr + rds_rdma_cookie_offset(args->cookie);
658 rdsdebug("RDS: rdma prepare nr_local %llu rva %llx rkey %x\n",
659 (unsigned long long)args->nr_local,
660 (unsigned long long)args->remote_vec.addr,
663 for (i = 0; i < args->nr_local; i++) {
664 struct rds_iovec *iov = &iovs[i];
665 /* don't need to check, rds_rdma_pages() verified nr will be +nonzero */
666 unsigned int nr = rds_pages_in_vec(iov);
668 rs->rs_user_addr = iov->addr;
669 rs->rs_user_bytes = iov->bytes;
671 /* If it's a WRITE operation, we want to pin the pages for reading.
672 * If it's a READ operation, we need to pin the pages for writing.
674 ret = rds_pin_pages(iov->addr, nr, pages, !op->op_write);
680 rdsdebug("RDS: nr_bytes %u nr %u iov->bytes %llu iov->addr %llx\n",
681 nr_bytes, nr, iov->bytes, iov->addr);
683 nr_bytes += iov->bytes;
685 for (j = 0; j < nr; j++) {
686 unsigned int offset = iov->addr & ~PAGE_MASK;
687 struct scatterlist *sg;
689 sg = &op->op_sg[op->op_nents + j];
690 sg_set_page(sg, pages[j],
691 min_t(unsigned int, iov->bytes, PAGE_SIZE - offset),
694 rdsdebug("RDS: sg->offset %x sg->len %x iov->addr %llx iov->bytes %llu\n",
695 sg->offset, sg->length, iov->addr, iov->bytes);
697 iov->addr += sg->length;
698 iov->bytes -= sg->length;
704 if (nr_bytes > args->remote_vec.bytes) {
705 rdsdebug("RDS nr_bytes %u remote_bytes %u do not match\n",
707 (unsigned int) args->remote_vec.bytes);
711 op->op_bytes = nr_bytes;
717 rds_rdma_free_op(op);
719 rds_stats_inc(s_send_rdma);
725 * The application wants us to pass an RDMA destination (aka MR)
728 int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
729 struct cmsghdr *cmsg)
736 if (cmsg->cmsg_len < CMSG_LEN(sizeof(rds_rdma_cookie_t)) ||
737 rm->m_rdma_cookie != 0)
740 memcpy(&rm->m_rdma_cookie, CMSG_DATA(cmsg), sizeof(rm->m_rdma_cookie));
742 /* We are reusing a previously mapped MR here. Most likely, the
743 * application has written to the buffer, so we need to explicitly
744 * flush those writes to RAM. Otherwise the HCA may not see them
745 * when doing a DMA from that buffer.
747 r_key = rds_rdma_cookie_key(rm->m_rdma_cookie);
749 spin_lock_irqsave(&rs->rs_rdma_lock, flags);
750 mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
752 err = -EINVAL; /* invalid r_key */
754 refcount_inc(&mr->r_refcount);
755 spin_unlock_irqrestore(&rs->rs_rdma_lock, flags);
758 mr->r_trans->sync_mr(mr->r_trans_private, DMA_TO_DEVICE);
759 rm->rdma.op_rdma_mr = mr;
765 * The application passes us an address range it wants to enable RDMA
766 * to/from. We map the area, and save the <R_Key,offset> pair
767 * in rm->m_rdma_cookie. This causes it to be sent along to the peer
768 * in an extension header.
770 int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
771 struct cmsghdr *cmsg)
773 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_get_mr_args)) ||
774 rm->m_rdma_cookie != 0)
777 return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie,
778 &rm->rdma.op_rdma_mr, rm->m_conn_path);
782 * Fill in rds_message for an atomic request.
784 int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
785 struct cmsghdr *cmsg)
787 struct page *page = NULL;
788 struct rds_atomic_args *args;
791 if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_atomic_args))
792 || rm->atomic.op_active)
795 args = CMSG_DATA(cmsg);
797 /* Nonmasked & masked cmsg ops converted to masked hw ops */
798 switch (cmsg->cmsg_type) {
799 case RDS_CMSG_ATOMIC_FADD:
800 rm->atomic.op_type = RDS_ATOMIC_TYPE_FADD;
801 rm->atomic.op_m_fadd.add = args->fadd.add;
802 rm->atomic.op_m_fadd.nocarry_mask = 0;
804 case RDS_CMSG_MASKED_ATOMIC_FADD:
805 rm->atomic.op_type = RDS_ATOMIC_TYPE_FADD;
806 rm->atomic.op_m_fadd.add = args->m_fadd.add;
807 rm->atomic.op_m_fadd.nocarry_mask = args->m_fadd.nocarry_mask;
809 case RDS_CMSG_ATOMIC_CSWP:
810 rm->atomic.op_type = RDS_ATOMIC_TYPE_CSWP;
811 rm->atomic.op_m_cswp.compare = args->cswp.compare;
812 rm->atomic.op_m_cswp.swap = args->cswp.swap;
813 rm->atomic.op_m_cswp.compare_mask = ~0;
814 rm->atomic.op_m_cswp.swap_mask = ~0;
816 case RDS_CMSG_MASKED_ATOMIC_CSWP:
817 rm->atomic.op_type = RDS_ATOMIC_TYPE_CSWP;
818 rm->atomic.op_m_cswp.compare = args->m_cswp.compare;
819 rm->atomic.op_m_cswp.swap = args->m_cswp.swap;
820 rm->atomic.op_m_cswp.compare_mask = args->m_cswp.compare_mask;
821 rm->atomic.op_m_cswp.swap_mask = args->m_cswp.swap_mask;
824 BUG(); /* should never happen */
827 rm->atomic.op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
828 rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT);
829 rm->atomic.op_active = 1;
830 rm->atomic.op_recverr = rs->rs_recverr;
831 rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1, &ret);
832 if (!rm->atomic.op_sg)
835 /* verify 8 byte-aligned */
836 if (args->local_addr & 0x7) {
841 ret = rds_pin_pages(args->local_addr, 1, &page, 1);
846 sg_set_page(rm->atomic.op_sg, page, 8, offset_in_page(args->local_addr));
848 if (rm->atomic.op_notify || rm->atomic.op_recverr) {
849 /* We allocate an uninitialized notifier here, because
850 * we don't want to do that in the completion handler. We
851 * would have to use GFP_ATOMIC there, and don't want to deal
852 * with failed allocations.
854 rm->atomic.op_notifier = kmalloc(sizeof(*rm->atomic.op_notifier), GFP_KERNEL);
855 if (!rm->atomic.op_notifier) {
860 rm->atomic.op_notifier->n_user_token = args->user_token;
861 rm->atomic.op_notifier->n_status = RDS_RDMA_SUCCESS;
864 rm->atomic.op_rkey = rds_rdma_cookie_key(args->cookie);
865 rm->atomic.op_remote_addr = args->remote_addr + rds_rdma_cookie_offset(args->cookie);
871 rm->atomic.op_active = 0;
872 kfree(rm->atomic.op_notifier);