Commit 99e6608c authored by Vishal Verma's avatar Vishal Verma Committed by Dan Williams
Browse files

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: default avatarVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 9e0e252a

block/genhd.c

+76 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/idr.h>

#include <linux/log2.h>

#include <linux/pm_runtime.h>

#include <linux/badblocks.h>



#include "blk.h"
@@ -505,6 +506,16 @@ static int exact_lock(dev_t devt, void *data) 
	return 0;

}



int disk_alloc_badblocks(struct gendisk *disk)

{

	disk->bb = kzalloc(sizeof(*(disk->bb)), GFP_KERNEL);

	if (!disk->bb)

		return -ENOMEM;



	return badblocks_init(disk->bb, 1);

}

EXPORT_SYMBOL(disk_alloc_badblocks);



static void register_disk(struct gendisk *disk)

{

	struct device *ddev = disk_to_dev(disk);
@@ -659,6 +670,11 @@ void del_gendisk(struct gendisk *disk) 
	blk_unregister_queue(disk);

	blk_unregister_region(disk_devt(disk), disk->minors);



	if (disk->bb) {

		badblocks_free(disk->bb);

		kfree(disk->bb);

	}



	part_stat_set_all(&disk->part0, 0);

	disk->part0.stamp = 0;
@@ -671,6 +687,63 @@ void del_gendisk(struct gendisk *disk) 
}

EXPORT_SYMBOL(del_gendisk);



/*

 * The gendisk usage of badblocks does not track acknowledgements for

 * badblocks. We always assume they are acknowledged.

 */

int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,

		   sector_t *first_bad, int *bad_sectors)

{

	if (!disk->bb)

		return 0;



	return badblocks_check(disk->bb, s, sectors, first_bad, bad_sectors);

}

EXPORT_SYMBOL(disk_check_badblocks);



int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors)

{

	if (!disk->bb)

		return 0;



	return badblocks_set(disk->bb, s, sectors, 1);

}

EXPORT_SYMBOL(disk_set_badblocks);



int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors)

{

	if (!disk->bb)

		return 0;



	return badblocks_clear(disk->bb, s, sectors);

}

EXPORT_SYMBOL(disk_clear_badblocks);



/* sysfs access to bad-blocks list. */

static ssize_t disk_badblocks_show(struct device *dev,

					struct device_attribute *attr,

					char *page)

{

	struct gendisk *disk = dev_to_disk(dev);



	if (!disk->bb)

		return sprintf(page, "\n");



	return badblocks_show(disk->bb, page, 0);

}



static ssize_t disk_badblocks_store(struct device *dev,

					struct device_attribute *attr,

					const char *page, size_t len)

{

	struct gendisk *disk = dev_to_disk(dev);



	if (!disk->bb)

		return -ENXIO;



	return badblocks_store(disk->bb, page, len, 0);

}



/**

 * get_gendisk - get partitioning information for a given device

 * @devt: device to get partitioning information for
@@ -989,6 +1062,8 @@ static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show, 
static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);

static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);

static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);

static DEVICE_ATTR(badblocks, S_IRUGO | S_IWUSR, disk_badblocks_show,

		disk_badblocks_store);

#ifdef CONFIG_FAIL_MAKE_REQUEST

static struct device_attribute dev_attr_fail =

	__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
@@ -1010,6 +1085,7 @@ static struct attribute *disk_attrs[] = { 
	&dev_attr_capability.attr,

	&dev_attr_stat.attr,

	&dev_attr_inflight.attr,

	&dev_attr_badblocks.attr,

#ifdef CONFIG_FAIL_MAKE_REQUEST

	&dev_attr_fail.attr,

#endif

include/linux/genhd.h

+7 −0
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ struct disk_part_tbl { 
};



struct disk_events;

struct badblocks;



#if defined(CONFIG_BLK_DEV_INTEGRITY)
@@ -213,6 +214,7 @@ struct gendisk { 
	struct kobject integrity_kobj;

#endif	/* CONFIG_BLK_DEV_INTEGRITY */

	int node_id;

	struct badblocks *bb;

};



static inline struct gendisk *part_to_disk(struct hd_struct *part)
@@ -433,6 +435,11 @@ extern void add_disk(struct gendisk *disk); 
extern void del_gendisk(struct gendisk *gp);

extern struct gendisk *get_gendisk(dev_t dev, int *partno);

extern struct block_device *bdget_disk(struct gendisk *disk, int partno);

int disk_alloc_badblocks(struct gendisk *disk);

extern int disk_check_badblocks(struct gendisk *disk, sector_t s, int sectors,

		   sector_t *first_bad, int *bad_sectors);

extern int disk_set_badblocks(struct gendisk *disk, sector_t s, int sectors);

extern int disk_clear_badblocks(struct gendisk *disk, sector_t s, int sectors);



extern void set_device_ro(struct block_device *bdev, int flag);

extern void set_disk_ro(struct gendisk *disk, int flag);

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