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-rw-r--r--block/genhd.c120
1 files changed, 115 insertions, 5 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 430626e..7bbfed0 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -16,6 +16,7 @@
#include <linux/kobj_map.h>
#include <linux/buffer_head.h>
#include <linux/mutex.h>
+#include <linux/idr.h>
#include "blk.h"
@@ -24,6 +25,15 @@ static DEFINE_MUTEX(block_class_lock);
struct kobject *block_depr;
#endif
+/* for extended dynamic devt allocation, currently only one major is used */
+#define MAX_EXT_DEVT (1 << MINORBITS)
+
+/* For extended devt allocation. ext_devt_mutex prevents look up
+ * results from going away underneath its user.
+ */
+static DEFINE_MUTEX(ext_devt_mutex);
+static DEFINE_IDR(ext_devt_idr);
+
static struct device_type disk_type;
/**
@@ -288,6 +298,74 @@ EXPORT_SYMBOL(unregister_blkdev);
static struct kobj_map *bdev_map;
+/**
+ * blk_alloc_devt - allocate a dev_t for a partition
+ * @part: partition to allocate dev_t for
+ * @gfp_mask: memory allocation flag
+ * @devt: out parameter for resulting dev_t
+ *
+ * Allocate a dev_t for block device.
+ *
+ * RETURNS:
+ * 0 on success, allocated dev_t is returned in *@devt. -errno on
+ * failure.
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
+{
+ struct gendisk *disk = part_to_disk(part);
+ int idx, rc;
+
+ /* in consecutive minor range? */
+ if (part->partno < disk->minors) {
+ *devt = MKDEV(disk->major, disk->first_minor + part->partno);
+ return 0;
+ }
+
+ /* allocate ext devt */
+ do {
+ if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
+ return -ENOMEM;
+ rc = idr_get_new(&ext_devt_idr, part, &idx);
+ } while (rc == -EAGAIN);
+
+ if (rc)
+ return rc;
+
+ if (idx > MAX_EXT_DEVT) {
+ idr_remove(&ext_devt_idr, idx);
+ return -EBUSY;
+ }
+
+ *devt = MKDEV(BLOCK_EXT_MAJOR, idx);
+ return 0;
+}
+
+/**
+ * blk_free_devt - free a dev_t
+ * @devt: dev_t to free
+ *
+ * Free @devt which was allocated using blk_alloc_devt().
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void blk_free_devt(dev_t devt)
+{
+ might_sleep();
+
+ if (devt == MKDEV(0, 0))
+ return;
+
+ if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
+ mutex_lock(&ext_devt_mutex);
+ idr_remove(&ext_devt_idr, MINOR(devt));
+ mutex_unlock(&ext_devt_mutex);
+ }
+}
+
/*
* Register device numbers dev..(dev+range-1)
* range must be nonzero
@@ -371,10 +449,27 @@ void unlink_gendisk(struct gendisk *disk)
*/
struct gendisk *get_gendisk(dev_t devt, int *partno)
{
- struct kobject *kobj = kobj_lookup(bdev_map, devt, partno);
- struct device *dev = kobj_to_dev(kobj);
+ struct gendisk *disk = NULL;
+
+ if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
+ struct kobject *kobj;
+
+ kobj = kobj_lookup(bdev_map, devt, partno);
+ if (kobj)
+ disk = dev_to_disk(kobj_to_dev(kobj));
+ } else {
+ struct hd_struct *part;
+
+ mutex_lock(&ext_devt_mutex);
+ part = idr_find(&ext_devt_idr, MINOR(devt));
+ if (part && get_disk(part_to_disk(part))) {
+ *partno = part->partno;
+ disk = part_to_disk(part);
+ }
+ mutex_unlock(&ext_devt_mutex);
+ }
- return kobj ? dev_to_disk(dev) : NULL;
+ return disk;
}
/**
@@ -878,17 +973,29 @@ struct gendisk *alloc_disk(int minors)
struct gendisk *alloc_disk_node(int minors, int node_id)
{
+ return alloc_disk_ext_node(minors, 0, node_id);
+}
+
+struct gendisk *alloc_disk_ext(int minors, int ext_minors)
+{
+ return alloc_disk_ext_node(minors, ext_minors, -1);
+}
+
+struct gendisk *alloc_disk_ext_node(int minors, int ext_minors, int node_id)
+{
struct gendisk *disk;
disk = kmalloc_node(sizeof(struct gendisk),
GFP_KERNEL | __GFP_ZERO, node_id);
if (disk) {
+ int tot_minors = minors + ext_minors;
+
if (!init_disk_stats(disk)) {
kfree(disk);
return NULL;
}
- if (minors > 1) {
- int size = (minors - 1) * sizeof(struct hd_struct *);
+ if (tot_minors > 1) {
+ int size = (tot_minors - 1) * sizeof(struct hd_struct *);
disk->__part = kmalloc_node(size,
GFP_KERNEL | __GFP_ZERO, node_id);
if (!disk->__part) {
@@ -898,6 +1005,7 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
}
}
disk->minors = minors;
+ disk->ext_minors = ext_minors;
rand_initialize_disk(disk);
disk->dev.class = &block_class;
disk->dev.type = &disk_type;
@@ -910,6 +1018,8 @@ struct gendisk *alloc_disk_node(int minors, int node_id)
EXPORT_SYMBOL(alloc_disk);
EXPORT_SYMBOL(alloc_disk_node);
+EXPORT_SYMBOL(alloc_disk_ext);
+EXPORT_SYMBOL(alloc_disk_ext_node);
struct kobject *get_disk(struct gendisk *disk)
{
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