Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 978 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/user_exp_rcv.c b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
new file mode 100644
index 000000000..4e417ed08
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/user_exp_rcv.c
@@ -0,0 +1,978 @@
+/*
+ * Copyright(c) 2015-2018 Intel Corporation.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * BSD LICENSE
+ *
+ * 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.
+ *  - Neither the name of Intel Corporation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+#include <asm/page.h>
+#include <linux/string.h>
+
+#include "mmu_rb.h"
+#include "user_exp_rcv.h"
+#include "trace.h"
+
+static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
+			    struct exp_tid_set *set,
+			    struct hfi1_filedata *fd);
+static u32 find_phys_blocks(struct tid_user_buf *tidbuf, unsigned int npages);
+static int set_rcvarray_entry(struct hfi1_filedata *fd,
+			      struct tid_user_buf *tbuf,
+			      u32 rcventry, struct tid_group *grp,
+			      u16 pageidx, unsigned int npages);
+static int tid_rb_insert(void *arg, struct mmu_rb_node *node);
+static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
+				    struct tid_rb_node *tnode);
+static void tid_rb_remove(void *arg, struct mmu_rb_node *node);
+static int tid_rb_invalidate(void *arg, struct mmu_rb_node *mnode);
+static int program_rcvarray(struct hfi1_filedata *fd, struct tid_user_buf *,
+			    struct tid_group *grp,
+			    unsigned int start, u16 count,
+			    u32 *tidlist, unsigned int *tididx,
+			    unsigned int *pmapped);
+static int unprogram_rcvarray(struct hfi1_filedata *fd, u32 tidinfo,
+			      struct tid_group **grp);
+static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node);
+
+static struct mmu_rb_ops tid_rb_ops = {
+	.insert = tid_rb_insert,
+	.remove = tid_rb_remove,
+	.invalidate = tid_rb_invalidate
+};
+
+/*
+ * Initialize context and file private data needed for Expected
+ * receive caching. This needs to be done after the context has
+ * been configured with the eager/expected RcvEntry counts.
+ */
+int hfi1_user_exp_rcv_init(struct hfi1_filedata *fd,
+			   struct hfi1_ctxtdata *uctxt)
+{
+	struct hfi1_devdata *dd = uctxt->dd;
+	int ret = 0;
+
+	fd->entry_to_rb = kcalloc(uctxt->expected_count,
+				  sizeof(struct rb_node *),
+				  GFP_KERNEL);
+	if (!fd->entry_to_rb)
+		return -ENOMEM;
+
+	if (!HFI1_CAP_UGET_MASK(uctxt->flags, TID_UNMAP)) {
+		fd->invalid_tid_idx = 0;
+		fd->invalid_tids = kcalloc(uctxt->expected_count,
+					   sizeof(*fd->invalid_tids),
+					   GFP_KERNEL);
+		if (!fd->invalid_tids) {
+			kfree(fd->entry_to_rb);
+			fd->entry_to_rb = NULL;
+			return -ENOMEM;
+		}
+
+		/*
+		 * Register MMU notifier callbacks. If the registration
+		 * fails, continue without TID caching for this context.
+		 */
+		ret = hfi1_mmu_rb_register(fd, fd->mm, &tid_rb_ops,
+					   dd->pport->hfi1_wq,
+					   &fd->handler);
+		if (ret) {
+			dd_dev_info(dd,
+				    "Failed MMU notifier registration %d\n",
+				    ret);
+			ret = 0;
+		}
+	}
+
+	/*
+	 * PSM does not have a good way to separate, count, and
+	 * effectively enforce a limit on RcvArray entries used by
+	 * subctxts (when context sharing is used) when TID caching
+	 * is enabled. To help with that, we calculate a per-process
+	 * RcvArray entry share and enforce that.
+	 * If TID caching is not in use, PSM deals with usage on its
+	 * own. In that case, we allow any subctxt to take all of the
+	 * entries.
+	 *
+	 * Make sure that we set the tid counts only after successful
+	 * init.
+	 */
+	spin_lock(&fd->tid_lock);
+	if (uctxt->subctxt_cnt && fd->handler) {
+		u16 remainder;
+
+		fd->tid_limit = uctxt->expected_count / uctxt->subctxt_cnt;
+		remainder = uctxt->expected_count % uctxt->subctxt_cnt;
+		if (remainder && fd->subctxt < remainder)
+			fd->tid_limit++;
+	} else {
+		fd->tid_limit = uctxt->expected_count;
+	}
+	spin_unlock(&fd->tid_lock);
+
+	return ret;
+}
+
+void hfi1_user_exp_rcv_free(struct hfi1_filedata *fd)
+{
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+
+	/*
+	 * The notifier would have been removed when the process'es mm
+	 * was freed.
+	 */
+	if (fd->handler) {
+		hfi1_mmu_rb_unregister(fd->handler);
+	} else {
+		mutex_lock(&uctxt->exp_mutex);
+		if (!EXP_TID_SET_EMPTY(uctxt->tid_full_list))
+			unlock_exp_tids(uctxt, &uctxt->tid_full_list, fd);
+		if (!EXP_TID_SET_EMPTY(uctxt->tid_used_list))
+			unlock_exp_tids(uctxt, &uctxt->tid_used_list, fd);
+		mutex_unlock(&uctxt->exp_mutex);
+	}
+
+	kfree(fd->invalid_tids);
+	fd->invalid_tids = NULL;
+
+	kfree(fd->entry_to_rb);
+	fd->entry_to_rb = NULL;
+}
+
+/**
+ * Release pinned receive buffer pages.
+ *
+ * @mapped - true if the pages have been DMA mapped. false otherwise.
+ * @idx - Index of the first page to unpin.
+ * @npages - No of pages to unpin.
+ *
+ * If the pages have been DMA mapped (indicated by mapped parameter), their
+ * info will be passed via a struct tid_rb_node. If they haven't been mapped,
+ * their info will be passed via a struct tid_user_buf.
+ */
+static void unpin_rcv_pages(struct hfi1_filedata *fd,
+			    struct tid_user_buf *tidbuf,
+			    struct tid_rb_node *node,
+			    unsigned int idx,
+			    unsigned int npages,
+			    bool mapped)
+{
+	struct page **pages;
+	struct hfi1_devdata *dd = fd->uctxt->dd;
+
+	if (mapped) {
+		pci_unmap_single(dd->pcidev, node->dma_addr,
+				 node->mmu.len, PCI_DMA_FROMDEVICE);
+		pages = &node->pages[idx];
+	} else {
+		pages = &tidbuf->pages[idx];
+	}
+	hfi1_release_user_pages(fd->mm, pages, npages, mapped);
+	fd->tid_n_pinned -= npages;
+}
+
+/**
+ * Pin receive buffer pages.
+ */
+static int pin_rcv_pages(struct hfi1_filedata *fd, struct tid_user_buf *tidbuf)
+{
+	int pinned;
+	unsigned int npages;
+	unsigned long vaddr = tidbuf->vaddr;
+	struct page **pages = NULL;
+	struct hfi1_devdata *dd = fd->uctxt->dd;
+
+	/* Get the number of pages the user buffer spans */
+	npages = num_user_pages(vaddr, tidbuf->length);
+	if (!npages)
+		return -EINVAL;
+
+	if (npages > fd->uctxt->expected_count) {
+		dd_dev_err(dd, "Expected buffer too big\n");
+		return -EINVAL;
+	}
+
+	/* Verify that access is OK for the user buffer */
+	if (!access_ok(VERIFY_WRITE, (void __user *)vaddr,
+		       npages * PAGE_SIZE)) {
+		dd_dev_err(dd, "Fail vaddr %p, %u pages, !access_ok\n",
+			   (void *)vaddr, npages);
+		return -EFAULT;
+	}
+	/* Allocate the array of struct page pointers needed for pinning */
+	pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
+	if (!pages)
+		return -ENOMEM;
+
+	/*
+	 * Pin all the pages of the user buffer. If we can't pin all the
+	 * pages, accept the amount pinned so far and program only that.
+	 * User space knows how to deal with partially programmed buffers.
+	 */
+	if (!hfi1_can_pin_pages(dd, fd->mm, fd->tid_n_pinned, npages)) {
+		kfree(pages);
+		return -ENOMEM;
+	}
+
+	pinned = hfi1_acquire_user_pages(fd->mm, vaddr, npages, true, pages);
+	if (pinned <= 0) {
+		kfree(pages);
+		return pinned;
+	}
+	tidbuf->pages = pages;
+	tidbuf->npages = npages;
+	fd->tid_n_pinned += pinned;
+	return pinned;
+}
+
+/*
+ * RcvArray entry allocation for Expected Receives is done by the
+ * following algorithm:
+ *
+ * The context keeps 3 lists of groups of RcvArray entries:
+ *   1. List of empty groups - tid_group_list
+ *      This list is created during user context creation and
+ *      contains elements which describe sets (of 8) of empty
+ *      RcvArray entries.
+ *   2. List of partially used groups - tid_used_list
+ *      This list contains sets of RcvArray entries which are
+ *      not completely used up. Another mapping request could
+ *      use some of all of the remaining entries.
+ *   3. List of full groups - tid_full_list
+ *      This is the list where sets that are completely used
+ *      up go.
+ *
+ * An attempt to optimize the usage of RcvArray entries is
+ * made by finding all sets of physically contiguous pages in a
+ * user's buffer.
+ * These physically contiguous sets are further split into
+ * sizes supported by the receive engine of the HFI. The
+ * resulting sets of pages are stored in struct tid_pageset,
+ * which describes the sets as:
+ *    * .count - number of pages in this set
+ *    * .idx - starting index into struct page ** array
+ *                    of this set
+ *
+ * From this point on, the algorithm deals with the page sets
+ * described above. The number of pagesets is divided by the
+ * RcvArray group size to produce the number of full groups
+ * needed.
+ *
+ * Groups from the 3 lists are manipulated using the following
+ * rules:
+ *   1. For each set of 8 pagesets, a complete group from
+ *      tid_group_list is taken, programmed, and moved to
+ *      the tid_full_list list.
+ *   2. For all remaining pagesets:
+ *      2.1 If the tid_used_list is empty and the tid_group_list
+ *          is empty, stop processing pageset and return only
+ *          what has been programmed up to this point.
+ *      2.2 If the tid_used_list is empty and the tid_group_list
+ *          is not empty, move a group from tid_group_list to
+ *          tid_used_list.
+ *      2.3 For each group is tid_used_group, program as much as
+ *          can fit into the group. If the group becomes fully
+ *          used, move it to tid_full_list.
+ */
+int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
+			    struct hfi1_tid_info *tinfo)
+{
+	int ret = 0, need_group = 0, pinned;
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct hfi1_devdata *dd = uctxt->dd;
+	unsigned int ngroups, pageidx = 0, pageset_count,
+		tididx = 0, mapped, mapped_pages = 0;
+	u32 *tidlist = NULL;
+	struct tid_user_buf *tidbuf;
+
+	if (!PAGE_ALIGNED(tinfo->vaddr))
+		return -EINVAL;
+
+	tidbuf = kzalloc(sizeof(*tidbuf), GFP_KERNEL);
+	if (!tidbuf)
+		return -ENOMEM;
+
+	tidbuf->vaddr = tinfo->vaddr;
+	tidbuf->length = tinfo->length;
+	tidbuf->psets = kcalloc(uctxt->expected_count, sizeof(*tidbuf->psets),
+				GFP_KERNEL);
+	if (!tidbuf->psets) {
+		kfree(tidbuf);
+		return -ENOMEM;
+	}
+
+	pinned = pin_rcv_pages(fd, tidbuf);
+	if (pinned <= 0) {
+		kfree(tidbuf->psets);
+		kfree(tidbuf);
+		return pinned;
+	}
+
+	/* Find sets of physically contiguous pages */
+	tidbuf->n_psets = find_phys_blocks(tidbuf, pinned);
+
+	/*
+	 * We don't need to access this under a lock since tid_used is per
+	 * process and the same process cannot be in hfi1_user_exp_rcv_clear()
+	 * and hfi1_user_exp_rcv_setup() at the same time.
+	 */
+	spin_lock(&fd->tid_lock);
+	if (fd->tid_used + tidbuf->n_psets > fd->tid_limit)
+		pageset_count = fd->tid_limit - fd->tid_used;
+	else
+		pageset_count = tidbuf->n_psets;
+	spin_unlock(&fd->tid_lock);
+
+	if (!pageset_count)
+		goto bail;
+
+	ngroups = pageset_count / dd->rcv_entries.group_size;
+	tidlist = kcalloc(pageset_count, sizeof(*tidlist), GFP_KERNEL);
+	if (!tidlist) {
+		ret = -ENOMEM;
+		goto nomem;
+	}
+
+	tididx = 0;
+
+	/*
+	 * From this point on, we are going to be using shared (between master
+	 * and subcontexts) context resources. We need to take the lock.
+	 */
+	mutex_lock(&uctxt->exp_mutex);
+	/*
+	 * The first step is to program the RcvArray entries which are complete
+	 * groups.
+	 */
+	while (ngroups && uctxt->tid_group_list.count) {
+		struct tid_group *grp =
+			tid_group_pop(&uctxt->tid_group_list);
+
+		ret = program_rcvarray(fd, tidbuf, grp,
+				       pageidx, dd->rcv_entries.group_size,
+				       tidlist, &tididx, &mapped);
+		/*
+		 * If there was a failure to program the RcvArray
+		 * entries for the entire group, reset the grp fields
+		 * and add the grp back to the free group list.
+		 */
+		if (ret <= 0) {
+			tid_group_add_tail(grp, &uctxt->tid_group_list);
+			hfi1_cdbg(TID,
+				  "Failed to program RcvArray group %d", ret);
+			goto unlock;
+		}
+
+		tid_group_add_tail(grp, &uctxt->tid_full_list);
+		ngroups--;
+		pageidx += ret;
+		mapped_pages += mapped;
+	}
+
+	while (pageidx < pageset_count) {
+		struct tid_group *grp, *ptr;
+		/*
+		 * If we don't have any partially used tid groups, check
+		 * if we have empty groups. If so, take one from there and
+		 * put in the partially used list.
+		 */
+		if (!uctxt->tid_used_list.count || need_group) {
+			if (!uctxt->tid_group_list.count)
+				goto unlock;
+
+			grp = tid_group_pop(&uctxt->tid_group_list);
+			tid_group_add_tail(grp, &uctxt->tid_used_list);
+			need_group = 0;
+		}
+		/*
+		 * There is an optimization opportunity here - instead of
+		 * fitting as many page sets as we can, check for a group
+		 * later on in the list that could fit all of them.
+		 */
+		list_for_each_entry_safe(grp, ptr, &uctxt->tid_used_list.list,
+					 list) {
+			unsigned use = min_t(unsigned, pageset_count - pageidx,
+					     grp->size - grp->used);
+
+			ret = program_rcvarray(fd, tidbuf, grp,
+					       pageidx, use, tidlist,
+					       &tididx, &mapped);
+			if (ret < 0) {
+				hfi1_cdbg(TID,
+					  "Failed to program RcvArray entries %d",
+					  ret);
+				goto unlock;
+			} else if (ret > 0) {
+				if (grp->used == grp->size)
+					tid_group_move(grp,
+						       &uctxt->tid_used_list,
+						       &uctxt->tid_full_list);
+				pageidx += ret;
+				mapped_pages += mapped;
+				need_group = 0;
+				/* Check if we are done so we break out early */
+				if (pageidx >= pageset_count)
+					break;
+			} else if (WARN_ON(ret == 0)) {
+				/*
+				 * If ret is 0, we did not program any entries
+				 * into this group, which can only happen if
+				 * we've screwed up the accounting somewhere.
+				 * Warn and try to continue.
+				 */
+				need_group = 1;
+			}
+		}
+	}
+unlock:
+	mutex_unlock(&uctxt->exp_mutex);
+nomem:
+	hfi1_cdbg(TID, "total mapped: tidpairs:%u pages:%u (%d)", tididx,
+		  mapped_pages, ret);
+	if (tididx) {
+		spin_lock(&fd->tid_lock);
+		fd->tid_used += tididx;
+		spin_unlock(&fd->tid_lock);
+		tinfo->tidcnt = tididx;
+		tinfo->length = mapped_pages * PAGE_SIZE;
+
+		if (copy_to_user(u64_to_user_ptr(tinfo->tidlist),
+				 tidlist, sizeof(tidlist[0]) * tididx)) {
+			/*
+			 * On failure to copy to the user level, we need to undo
+			 * everything done so far so we don't leak resources.
+			 */
+			tinfo->tidlist = (unsigned long)&tidlist;
+			hfi1_user_exp_rcv_clear(fd, tinfo);
+			tinfo->tidlist = 0;
+			ret = -EFAULT;
+			goto bail;
+		}
+	}
+
+	/*
+	 * If not everything was mapped (due to insufficient RcvArray entries,
+	 * for example), unpin all unmapped pages so we can pin them nex time.
+	 */
+	if (mapped_pages != pinned)
+		unpin_rcv_pages(fd, tidbuf, NULL, mapped_pages,
+				(pinned - mapped_pages), false);
+bail:
+	kfree(tidbuf->psets);
+	kfree(tidlist);
+	kfree(tidbuf->pages);
+	kfree(tidbuf);
+	return ret > 0 ? 0 : ret;
+}
+
+int hfi1_user_exp_rcv_clear(struct hfi1_filedata *fd,
+			    struct hfi1_tid_info *tinfo)
+{
+	int ret = 0;
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	u32 *tidinfo;
+	unsigned tididx;
+
+	if (unlikely(tinfo->tidcnt > fd->tid_used))
+		return -EINVAL;
+
+	tidinfo = memdup_user(u64_to_user_ptr(tinfo->tidlist),
+			      sizeof(tidinfo[0]) * tinfo->tidcnt);
+	if (IS_ERR(tidinfo))
+		return PTR_ERR(tidinfo);
+
+	mutex_lock(&uctxt->exp_mutex);
+	for (tididx = 0; tididx < tinfo->tidcnt; tididx++) {
+		ret = unprogram_rcvarray(fd, tidinfo[tididx], NULL);
+		if (ret) {
+			hfi1_cdbg(TID, "Failed to unprogram rcv array %d",
+				  ret);
+			break;
+		}
+	}
+	spin_lock(&fd->tid_lock);
+	fd->tid_used -= tididx;
+	spin_unlock(&fd->tid_lock);
+	tinfo->tidcnt = tididx;
+	mutex_unlock(&uctxt->exp_mutex);
+
+	kfree(tidinfo);
+	return ret;
+}
+
+int hfi1_user_exp_rcv_invalid(struct hfi1_filedata *fd,
+			      struct hfi1_tid_info *tinfo)
+{
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	unsigned long *ev = uctxt->dd->events +
+		(uctxt_offset(uctxt) + fd->subctxt);
+	u32 *array;
+	int ret = 0;
+
+	/*
+	 * copy_to_user() can sleep, which will leave the invalid_lock
+	 * locked and cause the MMU notifier to be blocked on the lock
+	 * for a long time.
+	 * Copy the data to a local buffer so we can release the lock.
+	 */
+	array = kcalloc(uctxt->expected_count, sizeof(*array), GFP_KERNEL);
+	if (!array)
+		return -EFAULT;
+
+	spin_lock(&fd->invalid_lock);
+	if (fd->invalid_tid_idx) {
+		memcpy(array, fd->invalid_tids, sizeof(*array) *
+		       fd->invalid_tid_idx);
+		memset(fd->invalid_tids, 0, sizeof(*fd->invalid_tids) *
+		       fd->invalid_tid_idx);
+		tinfo->tidcnt = fd->invalid_tid_idx;
+		fd->invalid_tid_idx = 0;
+		/*
+		 * Reset the user flag while still holding the lock.
+		 * Otherwise, PSM can miss events.
+		 */
+		clear_bit(_HFI1_EVENT_TID_MMU_NOTIFY_BIT, ev);
+	} else {
+		tinfo->tidcnt = 0;
+	}
+	spin_unlock(&fd->invalid_lock);
+
+	if (tinfo->tidcnt) {
+		if (copy_to_user((void __user *)tinfo->tidlist,
+				 array, sizeof(*array) * tinfo->tidcnt))
+			ret = -EFAULT;
+	}
+	kfree(array);
+
+	return ret;
+}
+
+static u32 find_phys_blocks(struct tid_user_buf *tidbuf, unsigned int npages)
+{
+	unsigned pagecount, pageidx, setcount = 0, i;
+	unsigned long pfn, this_pfn;
+	struct page **pages = tidbuf->pages;
+	struct tid_pageset *list = tidbuf->psets;
+
+	if (!npages)
+		return 0;
+
+	/*
+	 * Look for sets of physically contiguous pages in the user buffer.
+	 * This will allow us to optimize Expected RcvArray entry usage by
+	 * using the bigger supported sizes.
+	 */
+	pfn = page_to_pfn(pages[0]);
+	for (pageidx = 0, pagecount = 1, i = 1; i <= npages; i++) {
+		this_pfn = i < npages ? page_to_pfn(pages[i]) : 0;
+
+		/*
+		 * If the pfn's are not sequential, pages are not physically
+		 * contiguous.
+		 */
+		if (this_pfn != ++pfn) {
+			/*
+			 * At this point we have to loop over the set of
+			 * physically contiguous pages and break them down it
+			 * sizes supported by the HW.
+			 * There are two main constraints:
+			 *     1. The max buffer size is MAX_EXPECTED_BUFFER.
+			 *        If the total set size is bigger than that
+			 *        program only a MAX_EXPECTED_BUFFER chunk.
+			 *     2. The buffer size has to be a power of two. If
+			 *        it is not, round down to the closes power of
+			 *        2 and program that size.
+			 */
+			while (pagecount) {
+				int maxpages = pagecount;
+				u32 bufsize = pagecount * PAGE_SIZE;
+
+				if (bufsize > MAX_EXPECTED_BUFFER)
+					maxpages =
+						MAX_EXPECTED_BUFFER >>
+						PAGE_SHIFT;
+				else if (!is_power_of_2(bufsize))
+					maxpages =
+						rounddown_pow_of_two(bufsize) >>
+						PAGE_SHIFT;
+
+				list[setcount].idx = pageidx;
+				list[setcount].count = maxpages;
+				pagecount -= maxpages;
+				pageidx += maxpages;
+				setcount++;
+			}
+			pageidx = i;
+			pagecount = 1;
+			pfn = this_pfn;
+		} else {
+			pagecount++;
+		}
+	}
+	return setcount;
+}
+
+/**
+ * program_rcvarray() - program an RcvArray group with receive buffers
+ * @fd: filedata pointer
+ * @tbuf: pointer to struct tid_user_buf that has the user buffer starting
+ *	  virtual address, buffer length, page pointers, pagesets (array of
+ *	  struct tid_pageset holding information on physically contiguous
+ *	  chunks from the user buffer), and other fields.
+ * @grp: RcvArray group
+ * @start: starting index into sets array
+ * @count: number of struct tid_pageset's to program
+ * @tidlist: the array of u32 elements when the information about the
+ *           programmed RcvArray entries is to be encoded.
+ * @tididx: starting offset into tidlist
+ * @pmapped: (output parameter) number of pages programmed into the RcvArray
+ *           entries.
+ *
+ * This function will program up to 'count' number of RcvArray entries from the
+ * group 'grp'. To make best use of write-combining writes, the function will
+ * perform writes to the unused RcvArray entries which will be ignored by the
+ * HW. Each RcvArray entry will be programmed with a physically contiguous
+ * buffer chunk from the user's virtual buffer.
+ *
+ * Return:
+ * -EINVAL if the requested count is larger than the size of the group,
+ * -ENOMEM or -EFAULT on error from set_rcvarray_entry(), or
+ * number of RcvArray entries programmed.
+ */
+static int program_rcvarray(struct hfi1_filedata *fd, struct tid_user_buf *tbuf,
+			    struct tid_group *grp,
+			    unsigned int start, u16 count,
+			    u32 *tidlist, unsigned int *tididx,
+			    unsigned int *pmapped)
+{
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct hfi1_devdata *dd = uctxt->dd;
+	u16 idx;
+	u32 tidinfo = 0, rcventry, useidx = 0;
+	int mapped = 0;
+
+	/* Count should never be larger than the group size */
+	if (count > grp->size)
+		return -EINVAL;
+
+	/* Find the first unused entry in the group */
+	for (idx = 0; idx < grp->size; idx++) {
+		if (!(grp->map & (1 << idx))) {
+			useidx = idx;
+			break;
+		}
+		rcv_array_wc_fill(dd, grp->base + idx);
+	}
+
+	idx = 0;
+	while (idx < count) {
+		u16 npages, pageidx, setidx = start + idx;
+		int ret = 0;
+
+		/*
+		 * If this entry in the group is used, move to the next one.
+		 * If we go past the end of the group, exit the loop.
+		 */
+		if (useidx >= grp->size) {
+			break;
+		} else if (grp->map & (1 << useidx)) {
+			rcv_array_wc_fill(dd, grp->base + useidx);
+			useidx++;
+			continue;
+		}
+
+		rcventry = grp->base + useidx;
+		npages = tbuf->psets[setidx].count;
+		pageidx = tbuf->psets[setidx].idx;
+
+		ret = set_rcvarray_entry(fd, tbuf,
+					 rcventry, grp, pageidx,
+					 npages);
+		if (ret)
+			return ret;
+		mapped += npages;
+
+		tidinfo = rcventry2tidinfo(rcventry - uctxt->expected_base) |
+			EXP_TID_SET(LEN, npages);
+		tidlist[(*tididx)++] = tidinfo;
+		grp->used++;
+		grp->map |= 1 << useidx++;
+		idx++;
+	}
+
+	/* Fill the rest of the group with "blank" writes */
+	for (; useidx < grp->size; useidx++)
+		rcv_array_wc_fill(dd, grp->base + useidx);
+	*pmapped = mapped;
+	return idx;
+}
+
+static int set_rcvarray_entry(struct hfi1_filedata *fd,
+			      struct tid_user_buf *tbuf,
+			      u32 rcventry, struct tid_group *grp,
+			      u16 pageidx, unsigned int npages)
+{
+	int ret;
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct tid_rb_node *node;
+	struct hfi1_devdata *dd = uctxt->dd;
+	dma_addr_t phys;
+	struct page **pages = tbuf->pages + pageidx;
+
+	/*
+	 * Allocate the node first so we can handle a potential
+	 * failure before we've programmed anything.
+	 */
+	node = kzalloc(sizeof(*node) + (sizeof(struct page *) * npages),
+		       GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+
+	phys = pci_map_single(dd->pcidev,
+			      __va(page_to_phys(pages[0])),
+			      npages * PAGE_SIZE, PCI_DMA_FROMDEVICE);
+	if (dma_mapping_error(&dd->pcidev->dev, phys)) {
+		dd_dev_err(dd, "Failed to DMA map Exp Rcv pages 0x%llx\n",
+			   phys);
+		kfree(node);
+		return -EFAULT;
+	}
+
+	node->mmu.addr = tbuf->vaddr + (pageidx * PAGE_SIZE);
+	node->mmu.len = npages * PAGE_SIZE;
+	node->phys = page_to_phys(pages[0]);
+	node->npages = npages;
+	node->rcventry = rcventry;
+	node->dma_addr = phys;
+	node->grp = grp;
+	node->freed = false;
+	memcpy(node->pages, pages, sizeof(struct page *) * npages);
+
+	if (!fd->handler)
+		ret = tid_rb_insert(fd, &node->mmu);
+	else
+		ret = hfi1_mmu_rb_insert(fd->handler, &node->mmu);
+
+	if (ret) {
+		hfi1_cdbg(TID, "Failed to insert RB node %u 0x%lx, 0x%lx %d",
+			  node->rcventry, node->mmu.addr, node->phys, ret);
+		pci_unmap_single(dd->pcidev, phys, npages * PAGE_SIZE,
+				 PCI_DMA_FROMDEVICE);
+		kfree(node);
+		return -EFAULT;
+	}
+	hfi1_put_tid(dd, rcventry, PT_EXPECTED, phys, ilog2(npages) + 1);
+	trace_hfi1_exp_tid_reg(uctxt->ctxt, fd->subctxt, rcventry, npages,
+			       node->mmu.addr, node->phys, phys);
+	return 0;
+}
+
+static int unprogram_rcvarray(struct hfi1_filedata *fd, u32 tidinfo,
+			      struct tid_group **grp)
+{
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct hfi1_devdata *dd = uctxt->dd;
+	struct tid_rb_node *node;
+	u8 tidctrl = EXP_TID_GET(tidinfo, CTRL);
+	u32 tididx = EXP_TID_GET(tidinfo, IDX) << 1, rcventry;
+
+	if (tididx >= uctxt->expected_count) {
+		dd_dev_err(dd, "Invalid RcvArray entry (%u) index for ctxt %u\n",
+			   tididx, uctxt->ctxt);
+		return -EINVAL;
+	}
+
+	if (tidctrl == 0x3)
+		return -EINVAL;
+
+	rcventry = tididx + (tidctrl - 1);
+
+	node = fd->entry_to_rb[rcventry];
+	if (!node || node->rcventry != (uctxt->expected_base + rcventry))
+		return -EBADF;
+
+	if (grp)
+		*grp = node->grp;
+
+	if (!fd->handler)
+		cacheless_tid_rb_remove(fd, node);
+	else
+		hfi1_mmu_rb_remove(fd->handler, &node->mmu);
+
+	return 0;
+}
+
+static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node)
+{
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct hfi1_devdata *dd = uctxt->dd;
+
+	trace_hfi1_exp_tid_unreg(uctxt->ctxt, fd->subctxt, node->rcventry,
+				 node->npages, node->mmu.addr, node->phys,
+				 node->dma_addr);
+
+	/*
+	 * Make sure device has seen the write before we unpin the
+	 * pages.
+	 */
+	hfi1_put_tid(dd, node->rcventry, PT_INVALID_FLUSH, 0, 0);
+
+	unpin_rcv_pages(fd, NULL, node, 0, node->npages, true);
+
+	node->grp->used--;
+	node->grp->map &= ~(1 << (node->rcventry - node->grp->base));
+
+	if (node->grp->used == node->grp->size - 1)
+		tid_group_move(node->grp, &uctxt->tid_full_list,
+			       &uctxt->tid_used_list);
+	else if (!node->grp->used)
+		tid_group_move(node->grp, &uctxt->tid_used_list,
+			       &uctxt->tid_group_list);
+	kfree(node);
+}
+
+/*
+ * As a simple helper for hfi1_user_exp_rcv_free, this function deals with
+ * clearing nodes in the non-cached case.
+ */
+static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
+			    struct exp_tid_set *set,
+			    struct hfi1_filedata *fd)
+{
+	struct tid_group *grp, *ptr;
+	int i;
+
+	list_for_each_entry_safe(grp, ptr, &set->list, list) {
+		list_del_init(&grp->list);
+
+		for (i = 0; i < grp->size; i++) {
+			if (grp->map & (1 << i)) {
+				u16 rcventry = grp->base + i;
+				struct tid_rb_node *node;
+
+				node = fd->entry_to_rb[rcventry -
+							  uctxt->expected_base];
+				if (!node || node->rcventry != rcventry)
+					continue;
+
+				cacheless_tid_rb_remove(fd, node);
+			}
+		}
+	}
+}
+
+/*
+ * Always return 0 from this function.  A non-zero return indicates that the
+ * remove operation will be called and that memory should be unpinned.
+ * However, the driver cannot unpin out from under PSM.  Instead, retain the
+ * memory (by returning 0) and inform PSM that the memory is going away.  PSM
+ * will call back later when it has removed the memory from its list.
+ */
+static int tid_rb_invalidate(void *arg, struct mmu_rb_node *mnode)
+{
+	struct hfi1_filedata *fdata = arg;
+	struct hfi1_ctxtdata *uctxt = fdata->uctxt;
+	struct tid_rb_node *node =
+		container_of(mnode, struct tid_rb_node, mmu);
+
+	if (node->freed)
+		return 0;
+
+	trace_hfi1_exp_tid_inval(uctxt->ctxt, fdata->subctxt, node->mmu.addr,
+				 node->rcventry, node->npages, node->dma_addr);
+	node->freed = true;
+
+	spin_lock(&fdata->invalid_lock);
+	if (fdata->invalid_tid_idx < uctxt->expected_count) {
+		fdata->invalid_tids[fdata->invalid_tid_idx] =
+			rcventry2tidinfo(node->rcventry - uctxt->expected_base);
+		fdata->invalid_tids[fdata->invalid_tid_idx] |=
+			EXP_TID_SET(LEN, node->npages);
+		if (!fdata->invalid_tid_idx) {
+			unsigned long *ev;
+
+			/*
+			 * hfi1_set_uevent_bits() sets a user event flag
+			 * for all processes. Because calling into the
+			 * driver to process TID cache invalidations is
+			 * expensive and TID cache invalidations are
+			 * handled on a per-process basis, we can
+			 * optimize this to set the flag only for the
+			 * process in question.
+			 */
+			ev = uctxt->dd->events +
+				(uctxt_offset(uctxt) + fdata->subctxt);
+			set_bit(_HFI1_EVENT_TID_MMU_NOTIFY_BIT, ev);
+		}
+		fdata->invalid_tid_idx++;
+	}
+	spin_unlock(&fdata->invalid_lock);
+	return 0;
+}
+
+static int tid_rb_insert(void *arg, struct mmu_rb_node *node)
+{
+	struct hfi1_filedata *fdata = arg;
+	struct tid_rb_node *tnode =
+		container_of(node, struct tid_rb_node, mmu);
+	u32 base = fdata->uctxt->expected_base;
+
+	fdata->entry_to_rb[tnode->rcventry - base] = tnode;
+	return 0;
+}
+
+static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
+				    struct tid_rb_node *tnode)
+{
+	u32 base = fdata->uctxt->expected_base;
+
+	fdata->entry_to_rb[tnode->rcventry - base] = NULL;
+	clear_tid_node(fdata, tnode);
+}
+
+static void tid_rb_remove(void *arg, struct mmu_rb_node *node)
+{
+	struct hfi1_filedata *fdata = arg;
+	struct tid_rb_node *tnode =
+		container_of(node, struct tid_rb_node, mmu);
+
+	cacheless_tid_rb_remove(fdata, tnode);
+}