1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/nvdimm/badrange.c b/drivers/nvdimm/badrange.c
new file mode 100644
index 000000000000..0b67dcf43234
--- /dev/null
+++ b/drivers/nvdimm/badrange.c
@@ -0,0 +1,294 @@
+/*
+ * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ *
+ * 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.
+ */
+#include <linux/libnvdimm.h>
+#include <linux/badblocks.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/blkdev.h>
+#include <linux/device.h>
+#include <linux/ctype.h>
+#include <linux/ndctl.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include "nd-core.h"
+#include "nd.h"
+
+void badrange_init(struct badrange *badrange)
+{
+	INIT_LIST_HEAD(&badrange->list);
+	spin_lock_init(&badrange->lock);
+}
+EXPORT_SYMBOL_GPL(badrange_init);
+
+static void append_badrange_entry(struct badrange *badrange,
+		struct badrange_entry *bre, u64 addr, u64 length)
+{
+	lockdep_assert_held(&badrange->lock);
+	bre->start = addr;
+	bre->length = length;
+	list_add_tail(&bre->list, &badrange->list);
+}
+
+static int alloc_and_append_badrange_entry(struct badrange *badrange,
+		u64 addr, u64 length, gfp_t flags)
+{
+	struct badrange_entry *bre;
+
+	bre = kzalloc(sizeof(*bre), flags);
+	if (!bre)
+		return -ENOMEM;
+
+	append_badrange_entry(badrange, bre, addr, length);
+	return 0;
+}
+
+static int add_badrange(struct badrange *badrange, u64 addr, u64 length)
+{
+	struct badrange_entry *bre, *bre_new;
+
+	spin_unlock(&badrange->lock);
+	bre_new = kzalloc(sizeof(*bre_new), GFP_KERNEL);
+	spin_lock(&badrange->lock);
+
+	if (list_empty(&badrange->list)) {
+		if (!bre_new)
+			return -ENOMEM;
+		append_badrange_entry(badrange, bre_new, addr, length);
+		return 0;
+	}
+
+	/*
+	 * There is a chance this is a duplicate, check for those first.
+	 * This will be the common case as ARS_STATUS returns all known
+	 * errors in the SPA space, and we can't query it per region
+	 */
+	list_for_each_entry(bre, &badrange->list, list)
+		if (bre->start == addr) {
+			/* If length has changed, update this list entry */
+			if (bre->length != length)
+				bre->length = length;
+			kfree(bre_new);
+			return 0;
+		}
+
+	/*
+	 * If not a duplicate or a simple length update, add the entry as is,
+	 * as any overlapping ranges will get resolved when the list is consumed
+	 * and converted to badblocks
+	 */
+	if (!bre_new)
+		return -ENOMEM;
+	append_badrange_entry(badrange, bre_new, addr, length);
+
+	return 0;
+}
+
+int badrange_add(struct badrange *badrange, u64 addr, u64 length)
+{
+	int rc;
+
+	spin_lock(&badrange->lock);
+	rc = add_badrange(badrange, addr, length);
+	spin_unlock(&badrange->lock);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(badrange_add);
+
+void badrange_forget(struct badrange *badrange, phys_addr_t start,
+		unsigned int len)
+{
+	struct list_head *badrange_list = &badrange->list;
+	u64 clr_end = start + len - 1;
+	struct badrange_entry *bre, *next;
+
+	spin_lock(&badrange->lock);
+	WARN_ON_ONCE(list_empty(badrange_list));
+
+	/*
+	 * [start, clr_end] is the badrange interval being cleared.
+	 * [bre->start, bre_end] is the badrange_list entry we're comparing
+	 * the above interval against. The badrange list entry may need
+	 * to be modified (update either start or length), deleted, or
+	 * split into two based on the overlap characteristics
+	 */
+
+	list_for_each_entry_safe(bre, next, badrange_list, list) {
+		u64 bre_end = bre->start + bre->length - 1;
+
+		/* Skip intervals with no intersection */
+		if (bre_end < start)
+			continue;
+		if (bre->start >  clr_end)
+			continue;
+		/* Delete completely overlapped badrange entries */
+		if ((bre->start >= start) && (bre_end <= clr_end)) {
+			list_del(&bre->list);
+			kfree(bre);
+			continue;
+		}
+		/* Adjust start point of partially cleared entries */
+		if ((start <= bre->start) && (clr_end > bre->start)) {
+			bre->length -= clr_end - bre->start + 1;
+			bre->start = clr_end + 1;
+			continue;
+		}
+		/* Adjust bre->length for partial clearing at the tail end */
+		if ((bre->start < start) && (bre_end <= clr_end)) {
+			/* bre->start remains the same */
+			bre->length = start - bre->start;
+			continue;
+		}
+		/*
+		 * If clearing in the middle of an entry, we split it into
+		 * two by modifying the current entry to represent one half of
+		 * the split, and adding a new entry for the second half.
+		 */
+		if ((bre->start < start) && (bre_end > clr_end)) {
+			u64 new_start = clr_end + 1;
+			u64 new_len = bre_end - new_start + 1;
+
+			/* Add new entry covering the right half */
+			alloc_and_append_badrange_entry(badrange, new_start,
+					new_len, GFP_NOWAIT);
+			/* Adjust this entry to cover the left half */
+			bre->length = start - bre->start;
+			continue;
+		}
+	}
+	spin_unlock(&badrange->lock);
+}
+EXPORT_SYMBOL_GPL(badrange_forget);
+
+static void set_badblock(struct badblocks *bb, sector_t s, int num)
+{
+	dev_dbg(bb->dev, "Found a bad range (0x%llx, 0x%llx)\n",
+			(u64) s * 512, (u64) num * 512);
+	/* this isn't an error as the hardware will still throw an exception */
+	if (badblocks_set(bb, s, num, 1))
+		dev_info_once(bb->dev, "%s: failed for sector %llx\n",
+				__func__, (u64) s);
+}
+
+/**
+ * __add_badblock_range() - Convert a physical address range to bad sectors
+ * @bb:		badblocks instance to populate
+ * @ns_offset:	namespace offset where the error range begins (in bytes)
+ * @len:	number of bytes of badrange to be added
+ *
+ * This assumes that the range provided with (ns_offset, len) is within
+ * the bounds of physical addresses for this namespace, i.e. lies in the
+ * interval [ns_start, ns_start + ns_size)
+ */
+static void __add_badblock_range(struct badblocks *bb, u64 ns_offset, u64 len)
+{
+	const unsigned int sector_size = 512;
+	sector_t start_sector, end_sector;
+	u64 num_sectors;
+	u32 rem;
+
+	start_sector = div_u64(ns_offset, sector_size);
+	end_sector = div_u64_rem(ns_offset + len, sector_size, &rem);
+	if (rem)
+		end_sector++;
+	num_sectors = end_sector - start_sector;
+
+	if (unlikely(num_sectors > (u64)INT_MAX)) {
+		u64 remaining = num_sectors;
+		sector_t s = start_sector;
+
+		while (remaining) {
+			int done = min_t(u64, remaining, INT_MAX);
+
+			set_badblock(bb, s, done);
+			remaining -= done;
+			s += done;
+		}
+	} else
+		set_badblock(bb, start_sector, num_sectors);
+}
+
+static void badblocks_populate(struct badrange *badrange,
+		struct badblocks *bb, const struct resource *res)
+{
+	struct badrange_entry *bre;
+
+	if (list_empty(&badrange->list))
+		return;
+
+	list_for_each_entry(bre, &badrange->list, list) {
+		u64 bre_end = bre->start + bre->length - 1;
+
+		/* Discard intervals with no intersection */
+		if (bre_end < res->start)
+			continue;
+		if (bre->start >  res->end)
+			continue;
+		/* Deal with any overlap after start of the namespace */
+		if (bre->start >= res->start) {
+			u64 start = bre->start;
+			u64 len;
+
+			if (bre_end <= res->end)
+				len = bre->length;
+			else
+				len = res->start + resource_size(res)
+					- bre->start;
+			__add_badblock_range(bb, start - res->start, len);
+			continue;
+		}
+		/*
+		 * Deal with overlap for badrange starting before
+		 * the namespace.
+		 */
+		if (bre->start < res->start) {
+			u64 len;
+
+			if (bre_end < res->end)
+				len = bre->start + bre->length - res->start;
+			else
+				len = resource_size(res);
+			__add_badblock_range(bb, 0, len);
+		}
+	}
+}
+
+/**
+ * nvdimm_badblocks_populate() - Convert a list of badranges to badblocks
+ * @region: parent region of the range to interrogate
+ * @bb: badblocks instance to populate
+ * @res: resource range to consider
+ *
+ * The badrange list generated during bus initialization may contain
+ * multiple, possibly overlapping physical address ranges.  Compare each
+ * of these ranges to the resource range currently being initialized,
+ * and add badblocks entries for all matching sub-ranges
+ */
+void nvdimm_badblocks_populate(struct nd_region *nd_region,
+		struct badblocks *bb, const struct resource *res)
+{
+	struct nvdimm_bus *nvdimm_bus;
+
+	if (!is_memory(&nd_region->dev)) {
+		dev_WARN_ONCE(&nd_region->dev, 1,
+				"%s only valid for pmem regions\n", __func__);
+		return;
+	}
+	nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
+
+	nvdimm_bus_lock(&nvdimm_bus->dev);
+	badblocks_populate(&nvdimm_bus->badrange, bb, res);
+	nvdimm_bus_unlock(&nvdimm_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_badblocks_populate);