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block: Add badblock management for gendisks
NVDIMM devices, which can behave more like DRAM rather than block devices, may develop bad cache lines, or 'poison'. A block device exposed by the pmem driver can then consume poison via a read (or write), and cause a machine check. On platforms without machine check recovery features, this would mean a crash. The block device maintaining a runtime list of all known sectors that have poison can directly avoid this, and also provide a path forward to enable proper handling/recovery for DAX faults on such a device. Use the new badblock management interfaces to add a badblocks list to gendisks. Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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‎block/genhd.c

Lines changed: 76 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,7 @@
2020
#include <linux/idr.h>
2121
#include <linux/log2.h>
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#include <linux/pm_runtime.h>
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#include <linux/badblocks.h>
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2425
#include "blk.h"
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@@ -505,6 +506,16 @@ static int exact_lock(dev_t devt, void *data)
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return 0;
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}
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int disk_alloc_badblocks(struct gendisk *disk)
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{
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disk->bb = kzalloc(sizeof(*(disk->bb)), GFP_KERNEL);
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if (!disk->bb)
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return -ENOMEM;
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return badblocks_init(disk->bb, 1);
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}
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EXPORT_SYMBOL(disk_alloc_badblocks);
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static void register_disk(struct gendisk *disk)
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{
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struct device *ddev = disk_to_dev(disk);
@@ -659,6 +670,11 @@ void del_gendisk(struct gendisk *disk)
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blk_unregister_queue(disk);
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blk_unregister_region(disk_devt(disk), disk->minors);
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if (disk->bb) {
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badblocks_free(disk->bb);
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kfree(disk->bb);
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}
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part_stat_set_all(&disk->part0, 0);
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disk->part0.stamp = 0;
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@@ -671,6 +687,63 @@ void del_gendisk(struct gendisk *disk)
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}
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EXPORT_SYMBOL(del_gendisk);
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/*
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* The gendisk usage of badblocks does not track acknowledgements for
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* badblocks. We always assume they are acknowledged.
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*/
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int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,
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sector_t *first_bad, int *bad_sectors)
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{
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if (!disk->bb)
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return 0;
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return badblocks_check(disk->bb, s, sectors, first_bad, bad_sectors);
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}
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EXPORT_SYMBOL(disk_check_badblocks);
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int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors)
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{
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if (!disk->bb)
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return 0;
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return badblocks_set(disk->bb, s, sectors, 1);
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}
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EXPORT_SYMBOL(disk_set_badblocks);
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int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors)
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{
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if (!disk->bb)
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return 0;
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return badblocks_clear(disk->bb, s, sectors);
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}
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EXPORT_SYMBOL(disk_clear_badblocks);
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/* sysfs access to bad-blocks list. */
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static ssize_t disk_badblocks_show(struct device *dev,
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struct device_attribute *attr,
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char *page)
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{
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struct gendisk *disk = dev_to_disk(dev);
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if (!disk->bb)
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return sprintf(page, "\n");
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return badblocks_show(disk->bb, page, 0);
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}
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static ssize_t disk_badblocks_store(struct device *dev,
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struct device_attribute *attr,
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const char *page, size_t len)
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{
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struct gendisk *disk = dev_to_disk(dev);
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if (!disk->bb)
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return -ENXIO;
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return badblocks_store(disk->bb, page, len, 0);
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}
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/**
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* get_gendisk - get partitioning information for a given device
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* @devt: device to get partitioning information for
@@ -989,6 +1062,8 @@ static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
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static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
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static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
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static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
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static DEVICE_ATTR(badblocks, S_IRUGO | S_IWUSR, disk_badblocks_show,
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disk_badblocks_store);
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#ifdef CONFIG_FAIL_MAKE_REQUEST
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static struct device_attribute dev_attr_fail =
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__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
@@ -1010,6 +1085,7 @@ static struct attribute *disk_attrs[] = {
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&dev_attr_capability.attr,
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&dev_attr_stat.attr,
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&dev_attr_inflight.attr,
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&dev_attr_badblocks.attr,
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#ifdef CONFIG_FAIL_MAKE_REQUEST
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&dev_attr_fail.attr,
10151091
#endif

‎include/linux/genhd.h

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -162,6 +162,7 @@ struct disk_part_tbl {
162162
};
163163

164164
struct disk_events;
165+
struct badblocks;
165166

166167
#if defined(CONFIG_BLK_DEV_INTEGRITY)
167168

@@ -213,6 +214,7 @@ struct gendisk {
213214
struct kobject integrity_kobj;
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#endif /* CONFIG_BLK_DEV_INTEGRITY */
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int node_id;
217+
struct badblocks *bb;
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};
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static inline struct gendisk *part_to_disk(struct hd_struct *part)
@@ -433,6 +435,11 @@ extern void add_disk(struct gendisk *disk);
433435
extern void del_gendisk(struct gendisk *gp);
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extern struct gendisk *get_gendisk(dev_t dev, int *partno);
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extern struct block_device *bdget_disk(struct gendisk *disk, int partno);
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int disk_alloc_badblocks(struct gendisk *disk);
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extern int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,
440+
sector_t *first_bad, int *bad_sectors);
441+
extern int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors);
442+
extern int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors);
436443

437444
extern void set_device_ro(struct block_device *bdev, int flag);
438445
extern void set_disk_ro(struct gendisk *disk, int flag);

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