diff options
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 120 |
1 files changed, 115 insertions, 5 deletions
diff --git a/block/genhd.c b/block/genhd.c index 430626e440f..7bbfed05cec 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) { |