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-rw-r--r--block/genhd.c120
-rw-r--r--fs/partitions/check.c9
-rw-r--r--include/linux/genhd.h13
-rw-r--r--include/linux/major.h2
4 files changed, 135 insertions, 9 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)
{
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index c442f0a..0d4b7f2 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -333,6 +333,7 @@ void delete_partition(struct gendisk *disk, int partno)
if (!part)
return;
+ blk_free_devt(part_devt(part));
rcu_assign_pointer(disk->__part[partno-1], NULL);
kobject_put(part->holder_dir);
device_del(&part->dev);
@@ -352,6 +353,7 @@ int add_partition(struct gendisk *disk, int partno,
sector_t start, sector_t len, int flags)
{
struct hd_struct *p;
+ dev_t devt = MKDEV(0, 0);
int err;
if (disk->__part[partno - 1])
@@ -378,11 +380,15 @@ int add_partition(struct gendisk *disk, int partno,
"%s%d", disk->dev.bus_id, partno);
device_initialize(&p->dev);
- p->dev.devt = MKDEV(disk->major, disk->first_minor + partno);
p->dev.class = &block_class;
p->dev.type = &part_type;
p->dev.parent = &disk->dev;
+ err = blk_alloc_devt(p, &devt);
+ if (err)
+ goto out_put;
+ p->dev.devt = devt;
+
/* delay uevent until 'holders' subdir is created */
p->dev.uevent_suppress = 1;
err = device_add(&p->dev);
@@ -419,6 +425,7 @@ out_del:
device_del(&p->dev);
out_put:
put_device(&p->dev);
+ blk_free_devt(devt);
return err;
}
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index ac8a901..6fc5324 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -113,13 +113,15 @@ struct hd_struct {
#define GENHD_FL_FAIL 64
struct gendisk {
- /* major, first_minor and minors are input parameters only,
- * don't use directly. Use disk_devt() and disk_max_parts().
+ /* major, first_minor, minors and ext_minors are input
+ * parameters only, don't use directly. Use disk_devt() and
+ * disk_max_parts().
*/
int major; /* major number of driver */
int first_minor;
int minors; /* maximum number of minors, =1 for
* disks that can't be partitioned. */
+ int ext_minors; /* number of extended dynamic minors */
char disk_name[32]; /* name of major driver */
@@ -167,7 +169,7 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part)
static inline int disk_max_parts(struct gendisk *disk)
{
- return disk->minors - 1;
+ return disk->minors + disk->ext_minors - 1;
}
static inline dev_t disk_devt(struct gendisk *disk)
@@ -554,6 +556,8 @@ struct unixware_disklabel {
#define ADDPART_FLAG_RAID 1
#define ADDPART_FLAG_WHOLEDISK 2
+extern int blk_alloc_devt(struct hd_struct *part, dev_t *devt);
+extern void blk_free_devt(dev_t devt);
extern dev_t blk_lookup_devt(const char *name, int partno);
extern char *disk_name (struct gendisk *hd, int partno, char *buf);
@@ -564,6 +568,9 @@ extern void printk_all_partitions(void);
extern struct gendisk *alloc_disk_node(int minors, int node_id);
extern struct gendisk *alloc_disk(int minors);
+extern struct gendisk *alloc_disk_ext_node(int minors, int ext_minrs,
+ int node_id);
+extern struct gendisk *alloc_disk_ext(int minors, int ext_minors);
extern struct kobject *get_disk(struct gendisk *disk);
extern void put_disk(struct gendisk *disk);
extern void blk_register_region(dev_t devt, unsigned long range,
diff --git a/include/linux/major.h b/include/linux/major.h
index 53d5faf..8824945 100644
--- a/include/linux/major.h
+++ b/include/linux/major.h
@@ -170,4 +170,6 @@
#define VIOTAPE_MAJOR 230
+#define BLOCK_EXT_MAJOR 259
+
#endif
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