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block: use an xarray for disk->part_tbl
Now that no fast path lookups in the partition table are left, there is no point in micro-optimizing the data structure for it. Just use a bog standard xarray. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig
Jens Axboe
parent
0470dd9d5f
commit
a33df75c63
@ -865,7 +865,7 @@ void blk_queue_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
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* we do nothing special as far as the block layer is concerned.
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*/
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if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) ||
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disk_has_partitions(disk))
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!xa_empty(&disk->part_tbl))
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model = BLK_ZONED_NONE;
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break;
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case BLK_ZONED_NONE:
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@ -345,7 +345,6 @@ int bdev_add_partition(struct block_device *bdev, int partno,
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int bdev_del_partition(struct block_device *bdev, int partno);
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int bdev_resize_partition(struct block_device *bdev, int partno,
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sector_t start, sector_t length);
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int disk_expand_part_tbl(struct gendisk *disk, int target);
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int bio_add_hw_page(struct request_queue *q, struct bio *bio,
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struct page *page, unsigned int len, unsigned int offset,
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163
block/genhd.c
163
block/genhd.c
@ -161,15 +161,6 @@ static void part_in_flight_rw(struct block_device *part,
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inflight[1] = 0;
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}
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static struct block_device *__disk_get_part(struct gendisk *disk, int partno)
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{
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struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
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if (unlikely(partno < 0 || partno >= ptbl->len))
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return NULL;
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return rcu_dereference(ptbl->part[partno]);
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}
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/**
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* disk_part_iter_init - initialize partition iterator
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* @piter: iterator to initialize
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@ -204,41 +195,26 @@ void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
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*/
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struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
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{
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struct disk_part_tbl *ptbl;
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struct block_device *part;
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unsigned long idx;
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/* put the last partition */
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disk_part_iter_exit(piter);
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/* get part_tbl */
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rcu_read_lock();
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ptbl = rcu_dereference(piter->disk->part_tbl);
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/* iterate to the next partition */
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for (; piter->idx != ptbl->len; piter->idx += 1) {
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struct block_device *part;
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part = rcu_dereference(ptbl->part[piter->idx]);
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if (!part)
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continue;
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piter->part = bdgrab(part);
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if (!piter->part)
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continue;
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xa_for_each_start(&piter->disk->part_tbl, idx, part, piter->idx) {
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if (!bdev_nr_sectors(part) &&
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!(piter->flags & DISK_PITER_INCL_EMPTY) &&
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!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
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piter->idx == 0)) {
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bdput(piter->part);
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piter->part = NULL;
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piter->idx == 0))
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continue;
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}
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piter->part = bdgrab(part);
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if (!piter->part)
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continue;
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piter->idx += 1;
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piter->idx = idx + 1;
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break;
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}
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rcu_read_unlock();
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return piter->part;
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@ -260,42 +236,6 @@ void disk_part_iter_exit(struct disk_part_iter *piter)
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piter->part = NULL;
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}
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/**
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* disk_has_partitions
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* @disk: gendisk of interest
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*
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* Walk through the partition table and check if valid partition exists.
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*
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* CONTEXT:
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* Don't care.
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*
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* RETURNS:
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* True if the gendisk has at least one valid non-zero size partition.
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* Otherwise false.
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*/
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bool disk_has_partitions(struct gendisk *disk)
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{
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struct disk_part_tbl *ptbl;
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int i;
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bool ret = false;
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rcu_read_lock();
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ptbl = rcu_dereference(disk->part_tbl);
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/* Iterate partitions skipping the whole device at index 0 */
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for (i = 1; i < ptbl->len; i++) {
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if (rcu_dereference(ptbl->part[i])) {
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ret = true;
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break;
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}
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}
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rcu_read_unlock();
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return ret;
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}
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EXPORT_SYMBOL_GPL(disk_has_partitions);
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/*
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* Can be deleted altogether. Later.
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*
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@ -858,7 +798,7 @@ struct block_device *bdget_disk(struct gendisk *disk, int partno)
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struct block_device *bdev = NULL;
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rcu_read_lock();
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bdev = __disk_get_part(disk, partno);
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bdev = xa_load(&disk->part_tbl, partno);
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if (bdev && !bdgrab(bdev))
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bdev = NULL;
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rcu_read_unlock();
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@ -1248,83 +1188,6 @@ static const struct attribute_group *disk_attr_groups[] = {
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NULL
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};
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/**
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* disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
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* @disk: disk to replace part_tbl for
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* @new_ptbl: new part_tbl to install
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*
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* Replace disk->part_tbl with @new_ptbl in RCU-safe way. The
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* original ptbl is freed using RCU callback.
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*
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* LOCKING:
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* Matching bd_mutex locked or the caller is the only user of @disk.
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*/
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static void disk_replace_part_tbl(struct gendisk *disk,
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struct disk_part_tbl *new_ptbl)
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{
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struct disk_part_tbl *old_ptbl =
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rcu_dereference_protected(disk->part_tbl, 1);
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rcu_assign_pointer(disk->part_tbl, new_ptbl);
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if (old_ptbl) {
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rcu_assign_pointer(old_ptbl->last_lookup, NULL);
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kfree_rcu(old_ptbl, rcu_head);
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}
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}
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/**
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* disk_expand_part_tbl - expand disk->part_tbl
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* @disk: disk to expand part_tbl for
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* @partno: expand such that this partno can fit in
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*
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* Expand disk->part_tbl such that @partno can fit in. disk->part_tbl
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* uses RCU to allow unlocked dereferencing for stats and other stuff.
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*
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* LOCKING:
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* Matching bd_mutex locked or the caller is the only user of @disk.
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* Might sleep.
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*
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* RETURNS:
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* 0 on success, -errno on failure.
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*/
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int disk_expand_part_tbl(struct gendisk *disk, int partno)
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{
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struct disk_part_tbl *old_ptbl =
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rcu_dereference_protected(disk->part_tbl, 1);
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struct disk_part_tbl *new_ptbl;
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int len = old_ptbl ? old_ptbl->len : 0;
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int i, target;
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/*
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* check for int overflow, since we can get here from blkpg_ioctl()
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* with a user passed 'partno'.
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*/
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target = partno + 1;
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if (target < 0)
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return -EINVAL;
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/* disk_max_parts() is zero during initialization, ignore if so */
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if (disk_max_parts(disk) && target > disk_max_parts(disk))
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return -EINVAL;
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if (target <= len)
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return 0;
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new_ptbl = kzalloc_node(struct_size(new_ptbl, part, target), GFP_KERNEL,
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disk->node_id);
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if (!new_ptbl)
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return -ENOMEM;
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new_ptbl->len = target;
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for (i = 0; i < len; i++)
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rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
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disk_replace_part_tbl(disk, new_ptbl);
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return 0;
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}
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/**
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* disk_release - releases all allocated resources of the gendisk
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* @dev: the device representing this disk
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@ -1348,7 +1211,7 @@ static void disk_release(struct device *dev)
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blk_free_devt(dev->devt);
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disk_release_events(disk);
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kfree(disk->random);
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disk_replace_part_tbl(disk, NULL);
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xa_destroy(&disk->part_tbl);
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bdput(disk->part0);
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if (disk->queue)
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blk_put_queue(disk->queue);
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@ -1501,7 +1364,6 @@ dev_t blk_lookup_devt(const char *name, int partno)
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struct gendisk *__alloc_disk_node(int minors, int node_id)
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{
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struct gendisk *disk;
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struct disk_part_tbl *ptbl;
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if (minors > DISK_MAX_PARTS) {
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printk(KERN_ERR
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@ -1519,11 +1381,9 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
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goto out_free_disk;
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disk->node_id = node_id;
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if (disk_expand_part_tbl(disk, 0))
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goto out_bdput;
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ptbl = rcu_dereference_protected(disk->part_tbl, 1);
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rcu_assign_pointer(ptbl->part[0], disk->part0);
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xa_init(&disk->part_tbl);
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if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
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goto out_destroy_part_tbl;
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disk->minors = minors;
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rand_initialize_disk(disk);
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@ -1532,7 +1392,8 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
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device_initialize(disk_to_dev(disk));
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return disk;
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out_bdput:
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out_destroy_part_tbl:
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xa_destroy(&disk->part_tbl);
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bdput(disk->part0);
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out_free_disk:
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kfree(disk);
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@ -287,13 +287,7 @@ struct device_type part_type = {
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*/
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void delete_partition(struct block_device *part)
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{
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struct gendisk *disk = part->bd_disk;
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struct disk_part_tbl *ptbl =
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rcu_dereference_protected(disk->part_tbl, 1);
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rcu_assign_pointer(ptbl->part[part->bd_partno], NULL);
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rcu_assign_pointer(ptbl->last_lookup, NULL);
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xa_erase(&part->bd_disk->part_tbl, part->bd_partno);
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kobject_put(part->bd_holder_dir);
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device_del(&part->bd_device);
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@ -325,7 +319,6 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
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struct device *ddev = disk_to_dev(disk);
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struct device *pdev;
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struct block_device *bdev;
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struct disk_part_tbl *ptbl;
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const char *dname;
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int err;
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@ -347,12 +340,7 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
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break;
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}
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err = disk_expand_part_tbl(disk, partno);
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if (err)
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return ERR_PTR(err);
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ptbl = rcu_dereference_protected(disk->part_tbl, 1);
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if (ptbl->part[partno])
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if (xa_load(&disk->part_tbl, partno))
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return ERR_PTR(-EBUSY);
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bdev = bdev_alloc(disk, partno);
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@ -405,8 +393,10 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
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}
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/* everything is up and running, commence */
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err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL);
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if (err)
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goto out_del;
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bdev_add(bdev, devt);
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rcu_assign_pointer(ptbl->part[partno], bdev);
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/* suppress uevent if the disk suppresses it */
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if (!dev_get_uevent_suppress(ddev))
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@ -612,7 +602,7 @@ static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
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int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
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{
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struct parsed_partitions *state;
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int ret = -EAGAIN, p, highest;
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int ret = -EAGAIN, p;
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if (!disk_part_scan_enabled(disk))
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return 0;
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@ -660,15 +650,6 @@ int blk_add_partitions(struct gendisk *disk, struct block_device *bdev)
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/* tell userspace that the media / partition table may have changed */
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kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
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/*
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* Detect the highest partition number and preallocate disk->part_tbl.
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* This is an optimization and not strictly necessary.
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*/
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for (p = 1, highest = 0; p < state->limit; p++)
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if (state->parts[p].size)
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highest = p;
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disk_expand_part_tbl(disk, highest);
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for (p = 1; p < state->limit; p++)
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if (!blk_add_partition(disk, bdev, state, p))
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goto out_free_state;
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@ -32,6 +32,7 @@ extern struct class block_class;
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/workqueue.h>
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#include <linux/xarray.h>
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#define PARTITION_META_INFO_VOLNAMELTH 64
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/*
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@ -116,13 +117,6 @@ enum {
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DISK_EVENT_FLAG_UEVENT = 1 << 1,
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};
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struct disk_part_tbl {
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struct rcu_head rcu_head;
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int len;
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struct block_device __rcu *last_lookup;
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struct block_device __rcu *part[];
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};
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struct disk_events;
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struct badblocks;
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@ -148,12 +142,7 @@ struct gendisk {
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unsigned short events; /* supported events */
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unsigned short event_flags; /* flags related to event processing */
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/* Array of pointers to partitions indexed by partno.
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* Protected with matching bdev lock but stat and other
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* non-critical accesses use RCU. Always access through
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* helpers.
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*/
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struct disk_part_tbl __rcu *part_tbl;
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struct xarray part_tbl;
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struct block_device *part0;
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const struct block_device_operations *fops;
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@ -225,7 +214,7 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action);
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struct disk_part_iter {
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struct gendisk *disk;
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struct block_device *part;
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int idx;
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unsigned long idx;
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unsigned int flags;
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};
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@ -233,7 +222,6 @@ extern void disk_part_iter_init(struct disk_part_iter *piter,
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struct gendisk *disk, unsigned int flags);
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struct block_device *disk_part_iter_next(struct disk_part_iter *piter);
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extern void disk_part_iter_exit(struct disk_part_iter *piter);
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extern bool disk_has_partitions(struct gendisk *disk);
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/* block/genhd.c */
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extern void device_add_disk(struct device *parent, struct gendisk *disk,
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