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block: merge struct block_device and struct hd_struct
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Instead of having two structures that represent each block device with
different life time rules, merge them into a single one.  This also
greatly simplifies the reference counting rules, as we can use the inode
reference count as the main reference count for the new struct
block_device, with the device model reference front ending it for device
model interaction.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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@axboe
Christoph Hellwig authored and axboe committed Dec 1, 2020
1 parent 9499ffc commit 0d02129
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Showing 10 changed files with 108 additions and 230 deletions.
8 changes: 4 additions & 4 deletions block/blk-cgroup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -820,17 +820,17 @@ static void blkcg_fill_root_iostats(void)

class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
while ((dev = class_dev_iter_next(&iter))) {
struct gendisk *disk = dev_to_disk(dev);
struct hd_struct *part = disk_get_part(disk, 0);
struct blkcg_gq *blkg = blk_queue_root_blkg(disk->queue);
struct block_device *bdev = dev_to_bdev(dev);
struct blkcg_gq *blkg =
blk_queue_root_blkg(bdev->bd_disk->queue);
struct blkg_iostat tmp;
int cpu;

memset(&tmp, 0, sizeof(tmp));
for_each_possible_cpu(cpu) {
struct disk_stats *cpu_dkstats;

cpu_dkstats = per_cpu_ptr(part->bdev->bd_stats, cpu);
cpu_dkstats = per_cpu_ptr(bdev->bd_stats, cpu);
tmp.ios[BLKG_IOSTAT_READ] +=
cpu_dkstats->ios[STAT_READ];
tmp.ios[BLKG_IOSTAT_WRITE] +=
Expand Down
2 changes: 1 addition & 1 deletion block/blk.h
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Original file line number Diff line number Diff line change
Expand Up @@ -356,7 +356,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf);
#define ADDPART_FLAG_NONE 0
#define ADDPART_FLAG_RAID 1
#define ADDPART_FLAG_WHOLEDISK 2
void delete_partition(struct hd_struct *part);
void delete_partition(struct block_device *part);
int bdev_add_partition(struct block_device *bdev, int partno,
sector_t start, sector_t length);
int bdev_del_partition(struct block_device *bdev, int partno);
Expand Down
90 changes: 26 additions & 64 deletions block/genhd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -106,13 +106,14 @@ const char *bdevname(struct block_device *bdev, char *buf)
}
EXPORT_SYMBOL(bdevname);

static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
static void part_stat_read_all(struct block_device *part,
struct disk_stats *stat)
{
int cpu;

memset(stat, 0, sizeof(struct disk_stats));
for_each_possible_cpu(cpu) {
struct disk_stats *ptr = per_cpu_ptr(part->bdev->bd_stats, cpu);
struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);
int group;

for (group = 0; group < NR_STAT_GROUPS; group++) {
Expand Down Expand Up @@ -167,39 +168,6 @@ struct block_device *__disk_get_part(struct gendisk *disk, int partno)
return rcu_dereference(ptbl->part[partno]);
}

/**
* disk_get_part - get partition
* @disk: disk to look partition from
* @partno: partition number
*
* Look for partition @partno from @disk. If found, increment
* reference count and return it.
*
* CONTEXT:
* Don't care.
*
* RETURNS:
* Pointer to the found partition on success, NULL if not found.
*/
struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
{
struct block_device *bdev;
struct hd_struct *part;

rcu_read_lock();
bdev = __disk_get_part(disk, partno);
if (!bdev)
goto fail;
part = bdev->bd_part;
if (!kobject_get_unless_zero(&part_to_dev(part)->kobj))
goto fail;
rcu_read_unlock();
return part;
fail:
rcu_read_unlock();
return NULL;
}

/**
* disk_part_iter_init - initialize partition iterator
* @piter: iterator to initialize
Expand Down Expand Up @@ -859,7 +827,7 @@ void del_gendisk(struct gendisk *disk)
DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
while ((part = disk_part_iter_next(&piter))) {
invalidate_partition(part);
delete_partition(part->bd_part);
delete_partition(part);
}
disk_part_iter_exit(&piter);

Expand Down Expand Up @@ -952,13 +920,13 @@ void blk_request_module(dev_t devt)
*/
struct block_device *bdget_disk(struct gendisk *disk, int partno)
{
struct hd_struct *part;
struct block_device *bdev = NULL;

part = disk_get_part(disk, partno);
if (part)
bdev = bdget_part(part);
disk_put_part(part);
rcu_read_lock();
bdev = __disk_get_part(disk, partno);
if (bdev && !bdgrab(bdev))
bdev = NULL;
rcu_read_unlock();

return bdev;
}
Expand Down Expand Up @@ -1175,24 +1143,22 @@ static ssize_t disk_ro_show(struct device *dev,
ssize_t part_size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);

return sprintf(buf, "%llu\n", bdev_nr_sectors(p->bdev));
return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
}

ssize_t part_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
struct request_queue *q = part_to_disk(p)->queue;
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev->bd_disk->queue;
struct disk_stats stat;
unsigned int inflight;

part_stat_read_all(p, &stat);
part_stat_read_all(bdev, &stat);
if (queue_is_mq(q))
inflight = blk_mq_in_flight(q, p->bdev);
inflight = blk_mq_in_flight(q, bdev);
else
inflight = part_in_flight(p->bdev);
inflight = part_in_flight(bdev);

return sprintf(buf,
"%8lu %8lu %8llu %8u "
Expand Down Expand Up @@ -1227,14 +1193,14 @@ ssize_t part_stat_show(struct device *dev,
ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct hd_struct *p = dev_to_part(dev);
struct request_queue *q = part_to_disk(p)->queue;
struct block_device *bdev = dev_to_bdev(dev);
struct request_queue *q = bdev->bd_disk->queue;
unsigned int inflight[2];

if (queue_is_mq(q))
blk_mq_in_flight_rw(q, p->bdev, inflight);
blk_mq_in_flight_rw(q, bdev, inflight);
else
part_in_flight_rw(p->bdev, inflight);
part_in_flight_rw(bdev, inflight);

return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);
}
Expand Down Expand Up @@ -1282,20 +1248,17 @@ static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
ssize_t part_fail_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);

return sprintf(buf, "%d\n", p->bdev->bd_make_it_fail);
return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
}

ssize_t part_fail_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct hd_struct *p = dev_to_part(dev);
int i;

if (count > 0 && sscanf(buf, "%d", &i) > 0)
p->bdev->bd_make_it_fail = i;
dev_to_bdev(dev)->bd_make_it_fail = i;

return count;
}
Expand Down Expand Up @@ -1505,7 +1468,7 @@ static int diskstats_show(struct seq_file *seqf, void *v)

disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
while ((hd = disk_part_iter_next(&piter))) {
part_stat_read_all(hd->bd_part, &stat);
part_stat_read_all(hd, &stat);
if (queue_is_mq(gp->queue))
inflight = blk_mq_in_flight(gp->queue, hd);
else
Expand Down Expand Up @@ -1577,7 +1540,7 @@ dev_t blk_lookup_devt(const char *name, int partno)
class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
while ((dev = class_dev_iter_next(&iter))) {
struct gendisk *disk = dev_to_disk(dev);
struct hd_struct *part;
struct block_device *part;

if (strcmp(dev_name(dev), name))
continue;
Expand All @@ -1590,13 +1553,12 @@ dev_t blk_lookup_devt(const char *name, int partno)
MINOR(dev->devt) + partno);
break;
}
part = disk_get_part(disk, partno);
part = bdget_disk(disk, partno);
if (part) {
devt = part_devt(part);
disk_put_part(part);
devt = part->bd_dev;
bdput(part);
break;
}
disk_put_part(part);
}
class_dev_iter_exit(&iter);
return devt;
Expand Down
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