Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 763 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
new file mode 100644
index 000000000..f2734a5c5
--- /dev/null
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -0,0 +1,763 @@
+/*
+ * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
+ * Copyright (c) 2005 Cisco Systems.  All rights reserved.
+ * Copyright (c) 2005 Mellanox Technologies. 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/mm.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <asm/page.h>
+
+#include "mthca_memfree.h"
+#include "mthca_dev.h"
+#include "mthca_cmd.h"
+
+/*
+ * We allocate in as big chunks as we can, up to a maximum of 256 KB
+ * per chunk.
+ */
+enum {
+	MTHCA_ICM_ALLOC_SIZE   = 1 << 18,
+	MTHCA_TABLE_CHUNK_SIZE = 1 << 18
+};
+
+struct mthca_user_db_table {
+	struct mutex mutex;
+	struct {
+		u64                uvirt;
+		struct scatterlist mem;
+		int                refcount;
+	} page[];
+};
+
+static void mthca_free_icm_pages(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
+{
+	int i;
+
+	if (chunk->nsg > 0)
+		dma_unmap_sg(&dev->pdev->dev, chunk->mem, chunk->npages,
+			     DMA_BIDIRECTIONAL);
+
+	for (i = 0; i < chunk->npages; ++i)
+		__free_pages(sg_page(&chunk->mem[i]),
+			     get_order(chunk->mem[i].length));
+}
+
+static void mthca_free_icm_coherent(struct mthca_dev *dev, struct mthca_icm_chunk *chunk)
+{
+	int i;
+
+	for (i = 0; i < chunk->npages; ++i) {
+		dma_free_coherent(&dev->pdev->dev, chunk->mem[i].length,
+				  lowmem_page_address(sg_page(&chunk->mem[i])),
+				  sg_dma_address(&chunk->mem[i]));
+	}
+}
+
+void mthca_free_icm(struct mthca_dev *dev, struct mthca_icm *icm, int coherent)
+{
+	struct mthca_icm_chunk *chunk, *tmp;
+
+	if (!icm)
+		return;
+
+	list_for_each_entry_safe(chunk, tmp, &icm->chunk_list, list) {
+		if (coherent)
+			mthca_free_icm_coherent(dev, chunk);
+		else
+			mthca_free_icm_pages(dev, chunk);
+
+		kfree(chunk);
+	}
+
+	kfree(icm);
+}
+
+static int mthca_alloc_icm_pages(struct scatterlist *mem, int order, gfp_t gfp_mask)
+{
+	struct page *page;
+
+	/*
+	 * Use __GFP_ZERO because buggy firmware assumes ICM pages are
+	 * cleared, and subtle failures are seen if they aren't.
+	 */
+	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
+	if (!page)
+		return -ENOMEM;
+
+	sg_set_page(mem, page, PAGE_SIZE << order, 0);
+	return 0;
+}
+
+static int mthca_alloc_icm_coherent(struct device *dev, struct scatterlist *mem,
+				    int order, gfp_t gfp_mask)
+{
+	void *buf = dma_alloc_coherent(dev, PAGE_SIZE << order, &sg_dma_address(mem),
+				       gfp_mask);
+	if (!buf)
+		return -ENOMEM;
+
+	sg_set_buf(mem, buf, PAGE_SIZE << order);
+	BUG_ON(mem->offset);
+	sg_dma_len(mem) = PAGE_SIZE << order;
+	return 0;
+}
+
+struct mthca_icm *mthca_alloc_icm(struct mthca_dev *dev, int npages,
+				  gfp_t gfp_mask, int coherent)
+{
+	struct mthca_icm *icm;
+	struct mthca_icm_chunk *chunk = NULL;
+	int cur_order;
+	int ret;
+
+	/* We use sg_set_buf for coherent allocs, which assumes low memory */
+	BUG_ON(coherent && (gfp_mask & __GFP_HIGHMEM));
+
+	icm = kmalloc(sizeof *icm, gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
+	if (!icm)
+		return icm;
+
+	icm->refcount = 0;
+	INIT_LIST_HEAD(&icm->chunk_list);
+
+	cur_order = get_order(MTHCA_ICM_ALLOC_SIZE);
+
+	while (npages > 0) {
+		if (!chunk) {
+			chunk = kmalloc(sizeof *chunk,
+					gfp_mask & ~(__GFP_HIGHMEM | __GFP_NOWARN));
+			if (!chunk)
+				goto fail;
+
+			sg_init_table(chunk->mem, MTHCA_ICM_CHUNK_LEN);
+			chunk->npages = 0;
+			chunk->nsg    = 0;
+			list_add_tail(&chunk->list, &icm->chunk_list);
+		}
+
+		while (1 << cur_order > npages)
+			--cur_order;
+
+		if (coherent)
+			ret = mthca_alloc_icm_coherent(&dev->pdev->dev,
+						       &chunk->mem[chunk->npages],
+						       cur_order, gfp_mask);
+		else
+			ret = mthca_alloc_icm_pages(&chunk->mem[chunk->npages],
+						    cur_order, gfp_mask);
+
+		if (!ret) {
+			++chunk->npages;
+
+			if (coherent)
+				++chunk->nsg;
+			else if (chunk->npages == MTHCA_ICM_CHUNK_LEN) {
+				chunk->nsg =
+					dma_map_sg(&dev->pdev->dev, chunk->mem,
+						   chunk->npages,
+						   DMA_BIDIRECTIONAL);
+
+				if (chunk->nsg <= 0)
+					goto fail;
+			}
+
+			if (chunk->npages == MTHCA_ICM_CHUNK_LEN)
+				chunk = NULL;
+
+			npages -= 1 << cur_order;
+		} else {
+			--cur_order;
+			if (cur_order < 0)
+				goto fail;
+		}
+	}
+
+	if (!coherent && chunk) {
+		chunk->nsg = dma_map_sg(&dev->pdev->dev, chunk->mem,
+					chunk->npages, DMA_BIDIRECTIONAL);
+
+		if (chunk->nsg <= 0)
+			goto fail;
+	}
+
+	return icm;
+
+fail:
+	mthca_free_icm(dev, icm, coherent);
+	return NULL;
+}
+
+int mthca_table_get(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
+{
+	int i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
+	int ret = 0;
+
+	mutex_lock(&table->mutex);
+
+	if (table->icm[i]) {
+		++table->icm[i]->refcount;
+		goto out;
+	}
+
+	table->icm[i] = mthca_alloc_icm(dev, MTHCA_TABLE_CHUNK_SIZE >> PAGE_SHIFT,
+					(table->lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
+					__GFP_NOWARN, table->coherent);
+	if (!table->icm[i]) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (mthca_MAP_ICM(dev, table->icm[i],
+			  table->virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
+		mthca_free_icm(dev, table->icm[i], table->coherent);
+		table->icm[i] = NULL;
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	++table->icm[i]->refcount;
+
+out:
+	mutex_unlock(&table->mutex);
+	return ret;
+}
+
+void mthca_table_put(struct mthca_dev *dev, struct mthca_icm_table *table, int obj)
+{
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return;
+
+	i = (obj & (table->num_obj - 1)) * table->obj_size / MTHCA_TABLE_CHUNK_SIZE;
+
+	mutex_lock(&table->mutex);
+
+	if (--table->icm[i]->refcount == 0) {
+		mthca_UNMAP_ICM(dev, table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
+				MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
+		mthca_free_icm(dev, table->icm[i], table->coherent);
+		table->icm[i] = NULL;
+	}
+
+	mutex_unlock(&table->mutex);
+}
+
+void *mthca_table_find(struct mthca_icm_table *table, int obj, dma_addr_t *dma_handle)
+{
+	int idx, offset, dma_offset, i;
+	struct mthca_icm_chunk *chunk;
+	struct mthca_icm *icm;
+	struct page *page = NULL;
+
+	if (!table->lowmem)
+		return NULL;
+
+	mutex_lock(&table->mutex);
+
+	idx = (obj & (table->num_obj - 1)) * table->obj_size;
+	icm = table->icm[idx / MTHCA_TABLE_CHUNK_SIZE];
+	dma_offset = offset = idx % MTHCA_TABLE_CHUNK_SIZE;
+
+	if (!icm)
+		goto out;
+
+	list_for_each_entry(chunk, &icm->chunk_list, list) {
+		for (i = 0; i < chunk->npages; ++i) {
+			if (dma_handle && dma_offset >= 0) {
+				if (sg_dma_len(&chunk->mem[i]) > dma_offset)
+					*dma_handle = sg_dma_address(&chunk->mem[i]) +
+						dma_offset;
+				dma_offset -= sg_dma_len(&chunk->mem[i]);
+			}
+			/* DMA mapping can merge pages but not split them,
+			 * so if we found the page, dma_handle has already
+			 * been assigned to. */
+			if (chunk->mem[i].length > offset) {
+				page = sg_page(&chunk->mem[i]);
+				goto out;
+			}
+			offset -= chunk->mem[i].length;
+		}
+	}
+
+out:
+	mutex_unlock(&table->mutex);
+	return page ? lowmem_page_address(page) + offset : NULL;
+}
+
+int mthca_table_get_range(struct mthca_dev *dev, struct mthca_icm_table *table,
+			  int start, int end)
+{
+	int inc = MTHCA_TABLE_CHUNK_SIZE / table->obj_size;
+	int i, err;
+
+	for (i = start; i <= end; i += inc) {
+		err = mthca_table_get(dev, table, i);
+		if (err)
+			goto fail;
+	}
+
+	return 0;
+
+fail:
+	while (i > start) {
+		i -= inc;
+		mthca_table_put(dev, table, i);
+	}
+
+	return err;
+}
+
+void mthca_table_put_range(struct mthca_dev *dev, struct mthca_icm_table *table,
+			   int start, int end)
+{
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return;
+
+	for (i = start; i <= end; i += MTHCA_TABLE_CHUNK_SIZE / table->obj_size)
+		mthca_table_put(dev, table, i);
+}
+
+struct mthca_icm_table *mthca_alloc_icm_table(struct mthca_dev *dev,
+					      u64 virt, int obj_size,
+					      int nobj, int reserved,
+					      int use_lowmem, int use_coherent)
+{
+	struct mthca_icm_table *table;
+	int obj_per_chunk;
+	int num_icm;
+	unsigned chunk_size;
+	int i;
+
+	obj_per_chunk = MTHCA_TABLE_CHUNK_SIZE / obj_size;
+	num_icm = DIV_ROUND_UP(nobj, obj_per_chunk);
+
+	table = kmalloc(struct_size(table, icm, num_icm), GFP_KERNEL);
+	if (!table)
+		return NULL;
+
+	table->virt     = virt;
+	table->num_icm  = num_icm;
+	table->num_obj  = nobj;
+	table->obj_size = obj_size;
+	table->lowmem   = use_lowmem;
+	table->coherent = use_coherent;
+	mutex_init(&table->mutex);
+
+	for (i = 0; i < num_icm; ++i)
+		table->icm[i] = NULL;
+
+	for (i = 0; i * MTHCA_TABLE_CHUNK_SIZE < reserved * obj_size; ++i) {
+		chunk_size = MTHCA_TABLE_CHUNK_SIZE;
+		if ((i + 1) * MTHCA_TABLE_CHUNK_SIZE > nobj * obj_size)
+			chunk_size = nobj * obj_size - i * MTHCA_TABLE_CHUNK_SIZE;
+
+		table->icm[i] = mthca_alloc_icm(dev, chunk_size >> PAGE_SHIFT,
+						(use_lowmem ? GFP_KERNEL : GFP_HIGHUSER) |
+						__GFP_NOWARN, use_coherent);
+		if (!table->icm[i])
+			goto err;
+		if (mthca_MAP_ICM(dev, table->icm[i],
+				  virt + i * MTHCA_TABLE_CHUNK_SIZE)) {
+			mthca_free_icm(dev, table->icm[i], table->coherent);
+			table->icm[i] = NULL;
+			goto err;
+		}
+
+		/*
+		 * Add a reference to this ICM chunk so that it never
+		 * gets freed (since it contains reserved firmware objects).
+		 */
+		++table->icm[i]->refcount;
+	}
+
+	return table;
+
+err:
+	for (i = 0; i < num_icm; ++i)
+		if (table->icm[i]) {
+			mthca_UNMAP_ICM(dev, virt + i * MTHCA_TABLE_CHUNK_SIZE,
+					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
+			mthca_free_icm(dev, table->icm[i], table->coherent);
+		}
+
+	kfree(table);
+
+	return NULL;
+}
+
+void mthca_free_icm_table(struct mthca_dev *dev, struct mthca_icm_table *table)
+{
+	int i;
+
+	for (i = 0; i < table->num_icm; ++i)
+		if (table->icm[i]) {
+			mthca_UNMAP_ICM(dev,
+					table->virt + i * MTHCA_TABLE_CHUNK_SIZE,
+					MTHCA_TABLE_CHUNK_SIZE / MTHCA_ICM_PAGE_SIZE);
+			mthca_free_icm(dev, table->icm[i], table->coherent);
+		}
+
+	kfree(table);
+}
+
+static u64 mthca_uarc_virt(struct mthca_dev *dev, struct mthca_uar *uar, int page)
+{
+	return dev->uar_table.uarc_base +
+		uar->index * dev->uar_table.uarc_size +
+		page * MTHCA_ICM_PAGE_SIZE;
+}
+
+int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
+		      struct mthca_user_db_table *db_tab, int index, u64 uaddr)
+{
+	struct page *pages[1];
+	int ret = 0;
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return 0;
+
+	if (index < 0 || index > dev->uar_table.uarc_size / 8)
+		return -EINVAL;
+
+	mutex_lock(&db_tab->mutex);
+
+	i = index / MTHCA_DB_REC_PER_PAGE;
+
+	if ((db_tab->page[i].refcount >= MTHCA_DB_REC_PER_PAGE)       ||
+	    (db_tab->page[i].uvirt && db_tab->page[i].uvirt != uaddr) ||
+	    (uaddr & 4095)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (db_tab->page[i].refcount) {
+		++db_tab->page[i].refcount;
+		goto out;
+	}
+
+	ret = pin_user_pages_fast(uaddr & PAGE_MASK, 1,
+				  FOLL_WRITE | FOLL_LONGTERM, pages);
+	if (ret < 0)
+		goto out;
+
+	sg_set_page(&db_tab->page[i].mem, pages[0], MTHCA_ICM_PAGE_SIZE,
+			uaddr & ~PAGE_MASK);
+
+	ret = dma_map_sg(&dev->pdev->dev, &db_tab->page[i].mem, 1,
+			 DMA_TO_DEVICE);
+	if (ret < 0) {
+		unpin_user_page(pages[0]);
+		goto out;
+	}
+
+	ret = mthca_MAP_ICM_page(dev, sg_dma_address(&db_tab->page[i].mem),
+				 mthca_uarc_virt(dev, uar, i));
+	if (ret) {
+		dma_unmap_sg(&dev->pdev->dev, &db_tab->page[i].mem, 1,
+			     DMA_TO_DEVICE);
+		unpin_user_page(sg_page(&db_tab->page[i].mem));
+		goto out;
+	}
+
+	db_tab->page[i].uvirt    = uaddr;
+	db_tab->page[i].refcount = 1;
+
+out:
+	mutex_unlock(&db_tab->mutex);
+	return ret;
+}
+
+void mthca_unmap_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
+			 struct mthca_user_db_table *db_tab, int index)
+{
+	if (!mthca_is_memfree(dev))
+		return;
+
+	/*
+	 * To make our bookkeeping simpler, we don't unmap DB
+	 * pages until we clean up the whole db table.
+	 */
+
+	mutex_lock(&db_tab->mutex);
+
+	--db_tab->page[index / MTHCA_DB_REC_PER_PAGE].refcount;
+
+	mutex_unlock(&db_tab->mutex);
+}
+
+struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
+{
+	struct mthca_user_db_table *db_tab;
+	int npages;
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return NULL;
+
+	npages = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
+	db_tab = kmalloc(struct_size(db_tab, page, npages), GFP_KERNEL);
+	if (!db_tab)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&db_tab->mutex);
+	for (i = 0; i < npages; ++i) {
+		db_tab->page[i].refcount = 0;
+		db_tab->page[i].uvirt    = 0;
+		sg_init_table(&db_tab->page[i].mem, 1);
+	}
+
+	return db_tab;
+}
+
+void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
+			       struct mthca_user_db_table *db_tab)
+{
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return;
+
+	for (i = 0; i < dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE; ++i) {
+		if (db_tab->page[i].uvirt) {
+			mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1);
+			dma_unmap_sg(&dev->pdev->dev, &db_tab->page[i].mem, 1,
+				     DMA_TO_DEVICE);
+			unpin_user_page(sg_page(&db_tab->page[i].mem));
+		}
+	}
+
+	kfree(db_tab);
+}
+
+int mthca_alloc_db(struct mthca_dev *dev, enum mthca_db_type type,
+		   u32 qn, __be32 **db)
+{
+	int group;
+	int start, end, dir;
+	int i, j;
+	struct mthca_db_page *page;
+	int ret = 0;
+
+	mutex_lock(&dev->db_tab->mutex);
+
+	switch (type) {
+	case MTHCA_DB_TYPE_CQ_ARM:
+	case MTHCA_DB_TYPE_SQ:
+		group = 0;
+		start = 0;
+		end   = dev->db_tab->max_group1;
+		dir   = 1;
+		break;
+
+	case MTHCA_DB_TYPE_CQ_SET_CI:
+	case MTHCA_DB_TYPE_RQ:
+	case MTHCA_DB_TYPE_SRQ:
+		group = 1;
+		start = dev->db_tab->npages - 1;
+		end   = dev->db_tab->min_group2;
+		dir   = -1;
+		break;
+
+	default:
+		ret = -EINVAL;
+		goto out;
+	}
+
+	for (i = start; i != end; i += dir)
+		if (dev->db_tab->page[i].db_rec &&
+		    !bitmap_full(dev->db_tab->page[i].used,
+				 MTHCA_DB_REC_PER_PAGE)) {
+			page = dev->db_tab->page + i;
+			goto found;
+		}
+
+	for (i = start; i != end; i += dir)
+		if (!dev->db_tab->page[i].db_rec) {
+			page = dev->db_tab->page + i;
+			goto alloc;
+		}
+
+	if (dev->db_tab->max_group1 >= dev->db_tab->min_group2 - 1) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (group == 0)
+		++dev->db_tab->max_group1;
+	else
+		--dev->db_tab->min_group2;
+
+	page = dev->db_tab->page + end;
+
+alloc:
+	page->db_rec = dma_alloc_coherent(&dev->pdev->dev,
+					  MTHCA_ICM_PAGE_SIZE, &page->mapping,
+					  GFP_KERNEL);
+	if (!page->db_rec) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = mthca_MAP_ICM_page(dev, page->mapping,
+				 mthca_uarc_virt(dev, &dev->driver_uar, i));
+	if (ret) {
+		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
+				  page->db_rec, page->mapping);
+		goto out;
+	}
+
+	bitmap_zero(page->used, MTHCA_DB_REC_PER_PAGE);
+
+found:
+	j = find_first_zero_bit(page->used, MTHCA_DB_REC_PER_PAGE);
+	set_bit(j, page->used);
+
+	if (group == 1)
+		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
+
+	ret = i * MTHCA_DB_REC_PER_PAGE + j;
+
+	page->db_rec[j] = cpu_to_be64((qn << 8) | (type << 5));
+
+	*db = (__be32 *) &page->db_rec[j];
+
+out:
+	mutex_unlock(&dev->db_tab->mutex);
+
+	return ret;
+}
+
+void mthca_free_db(struct mthca_dev *dev, int type, int db_index)
+{
+	int i, j;
+	struct mthca_db_page *page;
+
+	i = db_index / MTHCA_DB_REC_PER_PAGE;
+	j = db_index % MTHCA_DB_REC_PER_PAGE;
+
+	page = dev->db_tab->page + i;
+
+	mutex_lock(&dev->db_tab->mutex);
+
+	page->db_rec[j] = 0;
+	if (i >= dev->db_tab->min_group2)
+		j = MTHCA_DB_REC_PER_PAGE - 1 - j;
+	clear_bit(j, page->used);
+
+	if (bitmap_empty(page->used, MTHCA_DB_REC_PER_PAGE) &&
+	    i >= dev->db_tab->max_group1 - 1) {
+		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
+
+		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
+				  page->db_rec, page->mapping);
+		page->db_rec = NULL;
+
+		if (i == dev->db_tab->max_group1) {
+			--dev->db_tab->max_group1;
+			/* XXX may be able to unmap more pages now */
+		}
+		if (i == dev->db_tab->min_group2)
+			++dev->db_tab->min_group2;
+	}
+
+	mutex_unlock(&dev->db_tab->mutex);
+}
+
+int mthca_init_db_tab(struct mthca_dev *dev)
+{
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return 0;
+
+	dev->db_tab = kmalloc(sizeof *dev->db_tab, GFP_KERNEL);
+	if (!dev->db_tab)
+		return -ENOMEM;
+
+	mutex_init(&dev->db_tab->mutex);
+
+	dev->db_tab->npages     = dev->uar_table.uarc_size / MTHCA_ICM_PAGE_SIZE;
+	dev->db_tab->max_group1 = 0;
+	dev->db_tab->min_group2 = dev->db_tab->npages - 1;
+
+	dev->db_tab->page = kmalloc_array(dev->db_tab->npages,
+					  sizeof(*dev->db_tab->page),
+					  GFP_KERNEL);
+	if (!dev->db_tab->page) {
+		kfree(dev->db_tab);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < dev->db_tab->npages; ++i)
+		dev->db_tab->page[i].db_rec = NULL;
+
+	return 0;
+}
+
+void mthca_cleanup_db_tab(struct mthca_dev *dev)
+{
+	int i;
+
+	if (!mthca_is_memfree(dev))
+		return;
+
+	/*
+	 * Because we don't always free our UARC pages when they
+	 * become empty to make mthca_free_db() simpler we need to
+	 * make a sweep through the doorbell pages and free any
+	 * leftover pages now.
+	 */
+	for (i = 0; i < dev->db_tab->npages; ++i) {
+		if (!dev->db_tab->page[i].db_rec)
+			continue;
+
+		if (!bitmap_empty(dev->db_tab->page[i].used, MTHCA_DB_REC_PER_PAGE))
+			mthca_warn(dev, "Kernel UARC page %d not empty\n", i);
+
+		mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1);
+
+		dma_free_coherent(&dev->pdev->dev, MTHCA_ICM_PAGE_SIZE,
+				  dev->db_tab->page[i].db_rec,
+				  dev->db_tab->page[i].mapping);
+	}
+
+	kfree(dev->db_tab->page);
+	kfree(dev->db_tab);
+}