From f331c0296f2a9fee0d396a70598b954062603015 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 3 Sep 2008 09:01:48 +0200 Subject: block: don't depend on consecutive minor space * Implement disk_devt() and part_devt() and use them to directly access devt instead of computing it from ->major and ->first_minor. Note that all references to ->major and ->first_minor outside of block layer is used to determine devt of the disk (the part0) and as ->major and ->first_minor will continue to represent devt for the disk, converting these users aren't strictly necessary. However, convert them for consistency. * Implement disk_max_parts() to avoid directly deferencing genhd->minors. * Update bdget_disk() such that it doesn't assume consecutive minor space. * Move devt computation from register_disk() to add_disk() and make it the only one (all other usages use the initially determined value). These changes clean up the code and will help disk->part dereference fix and extended block device numbers. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- include/linux/genhd.h | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index d1723c0a860..0ff75329199 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -111,10 +111,14 @@ 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(). + */ int major; /* major number of driver */ int first_minor; int minors; /* maximum number of minors, =1 for * disks that can't be partitioned. */ + char disk_name[32]; /* name of major driver */ struct hd_struct **part; /* [indexed by minor - 1] */ struct block_device_operations *fops; @@ -152,6 +156,21 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part) return NULL; } +static inline int disk_max_parts(struct gendisk *disk) +{ + return disk->minors - 1; +} + +static inline dev_t disk_devt(struct gendisk *disk) +{ + return disk->dev.devt; +} + +static inline dev_t part_devt(struct hd_struct *part) +{ + return part->dev.devt; +} + /* * Macros to operate on percpu disk statistics: * @@ -163,7 +182,7 @@ static inline struct hd_struct *disk_map_sector(struct gendisk *gendiskp, { struct hd_struct *part; int i; - for (i = 0; i < gendiskp->minors - 1; i++) { + for (i = 0; i < disk_max_parts(gendiskp); i++) { part = gendiskp->part[i]; if (part && part->start_sect <= sector && sector < part->start_sect + part->nr_sects) @@ -366,6 +385,7 @@ extern void add_disk(struct gendisk *disk); extern void del_gendisk(struct gendisk *gp); extern void unlink_gendisk(struct gendisk *gp); extern struct gendisk *get_gendisk(dev_t dev, int *partno); +extern struct block_device *bdget_disk(struct gendisk *disk, int partno); extern void set_device_ro(struct block_device *bdev, int flag); extern void set_disk_ro(struct gendisk *disk, int flag); @@ -553,11 +573,6 @@ extern void blk_register_region(dev_t devt, unsigned long range, void *data); extern void blk_unregister_region(dev_t devt, unsigned long range); -static inline struct block_device *bdget_disk(struct gendisk *disk, int partno) -{ - return bdget(MKDEV(disk->major, disk->first_minor) + partno); -} - #else /* CONFIG_BLOCK */ static inline void printk_all_partitions(void) { } -- cgit v1.2.3