*/
struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
{
- struct hd_struct *part;
+ struct hd_struct *part = NULL;
+ struct disk_part_tbl *ptbl;
- if (unlikely(partno < 0 || partno >= disk_max_parts(disk)))
+ if (unlikely(partno < 0))
return NULL;
+
rcu_read_lock();
- part = rcu_dereference(disk->__part[partno]);
- if (part)
- get_device(part_to_dev(part));
+
+ ptbl = rcu_dereference(disk->part_tbl);
+ if (likely(partno < ptbl->len)) {
+ part = rcu_dereference(ptbl->part[partno]);
+ if (part)
+ get_device(part_to_dev(part));
+ }
+
rcu_read_unlock();
return part;
void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
unsigned int flags)
{
+ struct disk_part_tbl *ptbl;
+
+ rcu_read_lock();
+ ptbl = rcu_dereference(disk->part_tbl);
+
piter->disk = disk;
piter->part = NULL;
if (flags & DISK_PITER_REVERSE)
- piter->idx = disk_max_parts(piter->disk) - 1;
+ piter->idx = ptbl->len - 1;
else if (flags & DISK_PITER_INCL_PART0)
piter->idx = 0;
else
piter->idx = 1;
piter->flags = flags;
+
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(disk_part_iter_init);
*/
struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
{
+ struct disk_part_tbl *ptbl;
int inc, end;
/* put the last partition */
disk_put_part(piter->part);
piter->part = NULL;
+ /* get part_tbl */
rcu_read_lock();
+ ptbl = rcu_dereference(piter->disk->part_tbl);
/* determine iteration parameters */
if (piter->flags & DISK_PITER_REVERSE) {
end = 0;
} else {
inc = 1;
- end = disk_max_parts(piter->disk);
+ end = ptbl->len;
}
/* iterate to the next partition */
for (; piter->idx != end; piter->idx += inc) {
struct hd_struct *part;
- part = rcu_dereference(piter->disk->__part[piter->idx]);
+ part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)
*/
struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
{
+ struct disk_part_tbl *ptbl;
int i;
- for (i = 1; i < disk_max_parts(disk); i++) {
- struct hd_struct *part = rcu_dereference(disk->__part[i]);
+ ptbl = rcu_dereference(disk->part_tbl);
+
+ for (i = 1; i < ptbl->len; i++) {
+ struct hd_struct *part = rcu_dereference(ptbl->part[i]);
if (part && part->start_sect <= sector &&
sector < part->start_sect + part->nr_sects)
NULL
};
+static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
+{
+ struct disk_part_tbl *ptbl =
+ container_of(head, struct disk_part_tbl, rcu_head);
+
+ kfree(ptbl);
+}
+
+/**
+ * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
+ * @disk: disk to replace part_tbl for
+ * @new_ptbl: new part_tbl to install
+ *
+ * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The
+ * original ptbl is freed using RCU callback.
+ *
+ * LOCKING:
+ * Matching bd_mutx locked.
+ */
+static void disk_replace_part_tbl(struct gendisk *disk,
+ struct disk_part_tbl *new_ptbl)
+{
+ struct disk_part_tbl *old_ptbl = disk->part_tbl;
+
+ rcu_assign_pointer(disk->part_tbl, new_ptbl);
+ if (old_ptbl)
+ call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
+}
+
+/**
+ * disk_expand_part_tbl - expand disk->part_tbl
+ * @disk: disk to expand part_tbl for
+ * @partno: expand such that this partno can fit in
+ *
+ * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl
+ * uses RCU to allow unlocked dereferencing for stats and other stuff.
+ *
+ * LOCKING:
+ * Matching bd_mutex locked, might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int disk_expand_part_tbl(struct gendisk *disk, int partno)
+{
+ struct disk_part_tbl *old_ptbl = disk->part_tbl;
+ struct disk_part_tbl *new_ptbl;
+ int len = old_ptbl ? old_ptbl->len : 0;
+ int target = partno + 1;
+ size_t size;
+ int i;
+
+ /* disk_max_parts() is zero during initialization, ignore if so */
+ if (disk_max_parts(disk) && target > disk_max_parts(disk))
+ return -EINVAL;
+
+ if (target <= len)
+ return 0;
+
+ size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
+ new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
+ if (!new_ptbl)
+ return -ENOMEM;
+
+ INIT_RCU_HEAD(&new_ptbl->rcu_head);
+ new_ptbl->len = target;
+
+ for (i = 0; i < len; i++)
+ rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
+
+ disk_replace_part_tbl(disk, new_ptbl);
+ return 0;
+}
+
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
kfree(disk->random);
- kfree(disk->__part);
+ disk_replace_part_tbl(disk, NULL);
free_part_stats(&disk->part0);
kfree(disk);
}
disk = kmalloc_node(sizeof(struct gendisk),
GFP_KERNEL | __GFP_ZERO, node_id);
if (disk) {
- int tot_minors = minors + ext_minors;
- int size = tot_minors * sizeof(struct hd_struct *);
-
if (!init_part_stats(&disk->part0)) {
kfree(disk);
return NULL;
}
-
- disk->__part = kmalloc_node(size, GFP_KERNEL | __GFP_ZERO,
- node_id);
- if (!disk->__part) {
- free_part_stats(&disk->part0);
+ if (disk_expand_part_tbl(disk, 0)) {
+ free_part_stats(&disk->part0);
kfree(disk);
return NULL;
}
- disk->__part[0] = &disk->part0;
+ disk->part_tbl->part[0] = &disk->part0;
disk->minors = minors;
disk->ext_minors = ext_minors;
device_initialize(disk_to_dev(disk));
INIT_WORK(&disk->async_notify,
media_change_notify_thread);
+ disk->node_id = node_id;
}
return disk;
}
projects / mirror_ubuntu-bionic-kernel.git / blobdiff