From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vishal Verma Subject: [PATCH 2/3] block: Add badblock management for gendisks Date: Fri, 20 Nov 2015 17:49:19 -0700 Message-ID: <1448066960-20119-3-git-send-email-vishal.l.verma@intel.com> References: <1448066960-20119-1-git-send-email-vishal.l.verma@intel.com> Return-path: In-Reply-To: <1448066960-20119-1-git-send-email-vishal.l.verma@intel.com> Sender: linux-raid-owner@vger.kernel.org To: linux-nvdimm@lists.01.org Cc: Vishal Verma , linux-block@vger.kernel.org, linux-raid@vger.kernel.org, linux-scsi@vger.kernel.org, Jens Axboe , NeilBrown , Jeff Moyer List-Id: linux-raid.ids 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 --- block/genhd.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/genhd.h | 6 +++++ 2 files changed, 70 insertions(+) diff --git a/block/genhd.c b/block/genhd.c index 0c706f3..4209c32 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "blk.h" @@ -505,6 +506,20 @@ static int exact_lock(dev_t devt, void *data) return 0; } +static void disk_alloc_badblocks(struct gendisk *disk) +{ + disk->bb = kzalloc(sizeof(disk->bb), GFP_KERNEL); + if (!disk->bb) { + pr_warn("%s: failed to allocate space for badblocks\n", + disk->disk_name); + return; + } + + if (badblocks_init(disk->bb, 1)) + pr_warn("%s: failed to initialize badblocks\n", + disk->disk_name); +} + static void register_disk(struct gendisk *disk) { struct device *ddev = disk_to_dev(disk); @@ -609,6 +624,7 @@ void add_disk(struct gendisk *disk) disk->first_minor = MINOR(devt); disk_alloc_events(disk); + disk_alloc_badblocks(disk); /* Register BDI before referencing it from bdev */ bdi = &disk->queue->backing_dev_info; @@ -657,6 +673,9 @@ void del_gendisk(struct gendisk *disk) blk_unregister_queue(disk); blk_unregister_region(disk_devt(disk), disk->minors); + badblocks_free(disk->bb); + kfree(disk->bb); + part_stat_set_all(&disk->part0, 0); disk->part0.stamp = 0; @@ -670,6 +689,48 @@ 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) +{ + 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) +{ + 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) +{ + 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); + + 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); + + return badblocks_store(disk->bb, page, len, 0); +} + /** * get_gendisk - get partitioning information for a given device * @devt: device to get partitioning information for @@ -988,6 +1049,8 @@ 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); @@ -1009,6 +1072,7 @@ 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 diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 2adbfa6..5563bde 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -162,6 +162,7 @@ struct disk_part_tbl { }; struct disk_events; +struct badblocks; struct gendisk { /* major, first_minor and minors are input parameters only, @@ -201,6 +202,7 @@ struct gendisk { struct blk_integrity *integrity; #endif int node_id; + struct badblocks *bb; }; static inline struct gendisk *part_to_disk(struct hd_struct *part) @@ -421,6 +423,10 @@ 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); +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); -- 2.5.0