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-rw-r--r--block/genhd.c85
1 files changed, 74 insertions, 11 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 1a7659327664..8b1e9f48957c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -38,8 +38,6 @@ static struct kobject *block_depr;
static DEFINE_SPINLOCK(ext_devt_lock);
static DEFINE_IDR(ext_devt_idr);
-static const struct device_type disk_type;
-
static void disk_check_events(struct disk_events *ev,
unsigned int *clearing_ptr);
static void disk_alloc_events(struct gendisk *disk);
@@ -876,11 +874,32 @@ static void invalidate_partition(struct gendisk *disk, int partno)
bdput(bdev);
}
+/**
+ * del_gendisk - remove the gendisk
+ * @disk: the struct gendisk to remove
+ *
+ * Removes the gendisk and all its associated resources. This deletes the
+ * partitions associated with the gendisk, and unregisters the associated
+ * request_queue.
+ *
+ * This is the counter to the respective __device_add_disk() call.
+ *
+ * The final removal of the struct gendisk happens when its refcount reaches 0
+ * with put_disk(), which should be called after del_gendisk(), if
+ * __device_add_disk() was used.
+ *
+ * Drivers exist which depend on the release of the gendisk to be synchronous,
+ * it should not be deferred.
+ *
+ * Context: can sleep
+ */
void del_gendisk(struct gendisk *disk)
{
struct disk_part_iter piter;
struct hd_struct *part;
+ might_sleep();
+
blk_integrity_del(disk);
disk_del_events(disk);
@@ -971,11 +990,15 @@ static ssize_t disk_badblocks_store(struct device *dev,
*
* This function gets the structure containing partitioning
* information for the given device @devt.
+ *
+ * Context: can sleep
*/
struct gendisk *get_gendisk(dev_t devt, int *partno)
{
struct gendisk *disk = NULL;
+ might_sleep();
+
if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
struct kobject *kobj;
@@ -1514,10 +1537,31 @@ int disk_expand_part_tbl(struct gendisk *disk, int partno)
return 0;
}
+/**
+ * disk_release - releases all allocated resources of the gendisk
+ * @dev: the device representing this disk
+ *
+ * This function releases all allocated resources of the gendisk.
+ *
+ * The struct gendisk refcount is incremented with get_gendisk() or
+ * get_disk_and_module(), and its refcount is decremented with
+ * put_disk_and_module() or put_disk(). Once the refcount reaches 0 this
+ * function is called.
+ *
+ * Drivers which used __device_add_disk() have a gendisk with a request_queue
+ * assigned. Since the request_queue sits on top of the gendisk for these
+ * drivers we also call blk_put_queue() for them, and we expect the
+ * request_queue refcount to reach 0 at this point, and so the request_queue
+ * will also be freed prior to the disk.
+ *
+ * Context: can sleep
+ */
static void disk_release(struct device *dev)
{
struct gendisk *disk = dev_to_disk(dev);
+ might_sleep();
+
blk_free_devt(dev->devt);
disk_release_events(disk);
kfree(disk->random);
@@ -1541,7 +1585,7 @@ static char *block_devnode(struct device *dev, umode_t *mode,
return NULL;
}
-static const struct device_type disk_type = {
+const struct device_type disk_type = {
.name = "disk",
.groups = disk_attr_groups,
.release = disk_release,
@@ -1727,6 +1771,15 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
}
EXPORT_SYMBOL(__alloc_disk_node);
+/**
+ * get_disk_and_module - increments the gendisk and gendisk fops module refcount
+ * @disk: the struct gendisk to to increment the refcount for
+ *
+ * This increments the refcount for the struct gendisk, and the gendisk's
+ * fops module owner.
+ *
+ * Context: Any context.
+ */
struct kobject *get_disk_and_module(struct gendisk *disk)
{
struct module *owner;
@@ -1747,6 +1800,16 @@ struct kobject *get_disk_and_module(struct gendisk *disk)
}
EXPORT_SYMBOL(get_disk_and_module);
+/**
+ * put_disk - decrements the gendisk refcount
+ * @disk: the struct gendisk to to decrement the refcount for
+ *
+ * This decrements the refcount for the struct gendisk. When this reaches 0
+ * we'll have disk_release() called.
+ *
+ * Context: Any context, but the last reference must not be dropped from
+ * atomic context.
+ */
void put_disk(struct gendisk *disk)
{
if (disk)
@@ -1754,9 +1817,15 @@ void put_disk(struct gendisk *disk)
}
EXPORT_SYMBOL(put_disk);
-/*
+/**
+ * put_disk_and_module - decrements the module and gendisk refcount
+ * @disk: the struct gendisk to to decrement the refcount for
+ *
* This is a counterpart of get_disk_and_module() and thus also of
* get_gendisk().
+ *
+ * Context: Any context, but the last reference must not be dropped from
+ * atomic context.
*/
void put_disk_and_module(struct gendisk *disk)
{
@@ -1985,18 +2054,12 @@ void disk_flush_events(struct gendisk *disk, unsigned int mask)
*/
unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
{
- const struct block_device_operations *bdops = disk->fops;
struct disk_events *ev = disk->ev;
unsigned int pending;
unsigned int clearing = mask;
- if (!ev) {
- /* for drivers still using the old ->media_changed method */
- if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
- bdops->media_changed && bdops->media_changed(disk))
- return DISK_EVENT_MEDIA_CHANGE;
+ if (!ev)
return 0;
- }
disk_block_events(disk);