| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 1991-1998 Linus Torvalds |
| * Re-organised Feb 1998 Russell King |
| */ |
| #include <linux/fs.h> |
| #include <linux/slab.h> |
| #include <linux/ctype.h> |
| #include <linux/genhd.h> |
| #include <linux/vmalloc.h> |
| #include <linux/blktrace_api.h> |
| #include <linux/raid/detect.h> |
| #include "check.h" |
| |
| static int (*check_part[])(struct parsed_partitions *) = { |
| /* |
| * Probe partition formats with tables at disk address 0 |
| * that also have an ADFS boot block at 0xdc0. |
| */ |
| #ifdef CONFIG_ACORN_PARTITION_ICS |
| adfspart_check_ICS, |
| #endif |
| #ifdef CONFIG_ACORN_PARTITION_POWERTEC |
| adfspart_check_POWERTEC, |
| #endif |
| #ifdef CONFIG_ACORN_PARTITION_EESOX |
| adfspart_check_EESOX, |
| #endif |
| |
| /* |
| * Now move on to formats that only have partition info at |
| * disk address 0xdc0. Since these may also have stale |
| * PC/BIOS partition tables, they need to come before |
| * the msdos entry. |
| */ |
| #ifdef CONFIG_ACORN_PARTITION_CUMANA |
| adfspart_check_CUMANA, |
| #endif |
| #ifdef CONFIG_ACORN_PARTITION_ADFS |
| adfspart_check_ADFS, |
| #endif |
| |
| #ifdef CONFIG_CMDLINE_PARTITION |
| cmdline_partition, |
| #endif |
| #ifdef CONFIG_EFI_PARTITION |
| efi_partition, /* this must come before msdos */ |
| #endif |
| #ifdef CONFIG_SGI_PARTITION |
| sgi_partition, |
| #endif |
| #ifdef CONFIG_LDM_PARTITION |
| ldm_partition, /* this must come before msdos */ |
| #endif |
| #ifdef CONFIG_MSDOS_PARTITION |
| msdos_partition, |
| #endif |
| #ifdef CONFIG_OSF_PARTITION |
| osf_partition, |
| #endif |
| #ifdef CONFIG_SUN_PARTITION |
| sun_partition, |
| #endif |
| #ifdef CONFIG_AMIGA_PARTITION |
| amiga_partition, |
| #endif |
| #ifdef CONFIG_ATARI_PARTITION |
| atari_partition, |
| #endif |
| #ifdef CONFIG_MAC_PARTITION |
| mac_partition, |
| #endif |
| #ifdef CONFIG_ULTRIX_PARTITION |
| ultrix_partition, |
| #endif |
| #ifdef CONFIG_IBM_PARTITION |
| ibm_partition, |
| #endif |
| #ifdef CONFIG_KARMA_PARTITION |
| karma_partition, |
| #endif |
| #ifdef CONFIG_SYSV68_PARTITION |
| sysv68_partition, |
| #endif |
| NULL |
| }; |
| |
| static struct parsed_partitions *allocate_partitions(struct gendisk *hd) |
| { |
| struct parsed_partitions *state; |
| int nr; |
| |
| state = kzalloc(sizeof(*state), GFP_KERNEL); |
| if (!state) |
| return NULL; |
| |
| nr = disk_max_parts(hd); |
| state->parts = vzalloc(array_size(nr, sizeof(state->parts[0]))); |
| if (!state->parts) { |
| kfree(state); |
| return NULL; |
| } |
| |
| state->limit = nr; |
| |
| return state; |
| } |
| |
| static void free_partitions(struct parsed_partitions *state) |
| { |
| vfree(state->parts); |
| kfree(state); |
| } |
| |
| static struct parsed_partitions *check_partition(struct gendisk *hd, |
| struct block_device *bdev) |
| { |
| struct parsed_partitions *state; |
| int i, res, err; |
| |
| state = allocate_partitions(hd); |
| if (!state) |
| return NULL; |
| state->pp_buf = (char *)__get_free_page(GFP_KERNEL); |
| if (!state->pp_buf) { |
| free_partitions(state); |
| return NULL; |
| } |
| state->pp_buf[0] = '\0'; |
| |
| state->bdev = bdev; |
| disk_name(hd, 0, state->name); |
| snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name); |
| if (isdigit(state->name[strlen(state->name)-1])) |
| sprintf(state->name, "p"); |
| |
| i = res = err = 0; |
| while (!res && check_part[i]) { |
| memset(state->parts, 0, state->limit * sizeof(state->parts[0])); |
| res = check_part[i++](state); |
| if (res < 0) { |
| /* |
| * We have hit an I/O error which we don't report now. |
| * But record it, and let the others do their job. |
| */ |
| err = res; |
| res = 0; |
| } |
| |
| } |
| if (res > 0) { |
| printk(KERN_INFO "%s", state->pp_buf); |
| |
| free_page((unsigned long)state->pp_buf); |
| return state; |
| } |
| if (state->access_beyond_eod) |
| err = -ENOSPC; |
| /* |
| * The partition is unrecognized. So report I/O errors if there were any |
| */ |
| if (err) |
| res = err; |
| if (res) { |
| strlcat(state->pp_buf, |
| " unable to read partition table\n", PAGE_SIZE); |
| printk(KERN_INFO "%s", state->pp_buf); |
| } |
| |
| free_page((unsigned long)state->pp_buf); |
| free_partitions(state); |
| return ERR_PTR(res); |
| } |
| |
| static ssize_t part_partition_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| |
| return sprintf(buf, "%d\n", p->partno); |
| } |
| |
| static ssize_t part_start_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| |
| return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect); |
| } |
| |
| static ssize_t part_ro_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| return sprintf(buf, "%d\n", p->policy ? 1 : 0); |
| } |
| |
| static ssize_t part_alignment_offset_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset); |
| } |
| |
| static ssize_t part_discard_alignment_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| return sprintf(buf, "%u\n", p->discard_alignment); |
| } |
| |
| static DEVICE_ATTR(partition, 0444, part_partition_show, NULL); |
| static DEVICE_ATTR(start, 0444, part_start_show, NULL); |
| static DEVICE_ATTR(size, 0444, part_size_show, NULL); |
| static DEVICE_ATTR(ro, 0444, part_ro_show, NULL); |
| static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL); |
| static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL); |
| static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); |
| static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); |
| #ifdef CONFIG_FAIL_MAKE_REQUEST |
| static struct device_attribute dev_attr_fail = |
| __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); |
| #endif |
| |
| static struct attribute *part_attrs[] = { |
| &dev_attr_partition.attr, |
| &dev_attr_start.attr, |
| &dev_attr_size.attr, |
| &dev_attr_ro.attr, |
| &dev_attr_alignment_offset.attr, |
| &dev_attr_discard_alignment.attr, |
| &dev_attr_stat.attr, |
| &dev_attr_inflight.attr, |
| #ifdef CONFIG_FAIL_MAKE_REQUEST |
| &dev_attr_fail.attr, |
| #endif |
| NULL |
| }; |
| |
| static struct attribute_group part_attr_group = { |
| .attrs = part_attrs, |
| }; |
| |
| static const struct attribute_group *part_attr_groups[] = { |
| &part_attr_group, |
| #ifdef CONFIG_BLK_DEV_IO_TRACE |
| &blk_trace_attr_group, |
| #endif |
| NULL |
| }; |
| |
| static void part_release(struct device *dev) |
| { |
| struct hd_struct *p = dev_to_part(dev); |
| blk_free_devt(dev->devt); |
| hd_free_part(p); |
| kfree(p); |
| } |
| |
| static int part_uevent(struct device *dev, struct kobj_uevent_env *env) |
| { |
| struct hd_struct *part = dev_to_part(dev); |
| |
| add_uevent_var(env, "PARTN=%u", part->partno); |
| if (part->info && part->info->volname[0]) |
| add_uevent_var(env, "PARTNAME=%s", part->info->volname); |
| return 0; |
| } |
| |
| struct device_type part_type = { |
| .name = "partition", |
| .groups = part_attr_groups, |
| .release = part_release, |
| .uevent = part_uevent, |
| }; |
| |
| static void hd_struct_free_work(struct work_struct *work) |
| { |
| struct hd_struct *part = |
| container_of(to_rcu_work(work), struct hd_struct, rcu_work); |
| |
| part->start_sect = 0; |
| part->nr_sects = 0; |
| part_stat_set_all(part, 0); |
| put_device(part_to_dev(part)); |
| } |
| |
| static void hd_struct_free(struct percpu_ref *ref) |
| { |
| struct hd_struct *part = container_of(ref, struct hd_struct, ref); |
| struct gendisk *disk = part_to_disk(part); |
| struct disk_part_tbl *ptbl = |
| rcu_dereference_protected(disk->part_tbl, 1); |
| |
| rcu_assign_pointer(ptbl->last_lookup, NULL); |
| put_device(disk_to_dev(disk)); |
| |
| INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work); |
| queue_rcu_work(system_wq, &part->rcu_work); |
| } |
| |
| int hd_ref_init(struct hd_struct *part) |
| { |
| if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL)) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| /* |
| * Must be called either with bd_mutex held, before a disk can be opened or |
| * after all disk users are gone. |
| */ |
| void delete_partition(struct gendisk *disk, struct hd_struct *part) |
| { |
| struct disk_part_tbl *ptbl = |
| rcu_dereference_protected(disk->part_tbl, 1); |
| |
| /* |
| * ->part_tbl is referenced in this part's release handler, so |
| * we have to hold the disk device |
| */ |
| get_device(disk_to_dev(part_to_disk(part))); |
| rcu_assign_pointer(ptbl->part[part->partno], NULL); |
| kobject_put(part->holder_dir); |
| device_del(part_to_dev(part)); |
| |
| /* |
| * Remove gendisk pointer from idr so that it cannot be looked up |
| * while RCU period before freeing gendisk is running to prevent |
| * use-after-free issues. Note that the device number stays |
| * "in-use" until we really free the gendisk. |
| */ |
| blk_invalidate_devt(part_devt(part)); |
| percpu_ref_kill(&part->ref); |
| } |
| |
| static ssize_t whole_disk_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| return 0; |
| } |
| static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL); |
| |
| /* |
| * Must be called either with bd_mutex held, before a disk can be opened or |
| * after all disk users are gone. |
| */ |
| static struct hd_struct *add_partition(struct gendisk *disk, int partno, |
| sector_t start, sector_t len, int flags, |
| struct partition_meta_info *info) |
| { |
| struct hd_struct *p; |
| dev_t devt = MKDEV(0, 0); |
| struct device *ddev = disk_to_dev(disk); |
| struct device *pdev; |
| struct disk_part_tbl *ptbl; |
| const char *dname; |
| int err; |
| |
| /* |
| * Partitions are not supported on zoned block devices that are used as |
| * such. |
| */ |
| switch (disk->queue->limits.zoned) { |
| case BLK_ZONED_HM: |
| pr_warn("%s: partitions not supported on host managed zoned block device\n", |
| disk->disk_name); |
| return ERR_PTR(-ENXIO); |
| case BLK_ZONED_HA: |
| pr_info("%s: disabling host aware zoned block device support due to partitions\n", |
| disk->disk_name); |
| disk->queue->limits.zoned = BLK_ZONED_NONE; |
| break; |
| case BLK_ZONED_NONE: |
| break; |
| } |
| |
| err = disk_expand_part_tbl(disk, partno); |
| if (err) |
| return ERR_PTR(err); |
| ptbl = rcu_dereference_protected(disk->part_tbl, 1); |
| |
| if (ptbl->part[partno]) |
| return ERR_PTR(-EBUSY); |
| |
| p = kzalloc(sizeof(*p), GFP_KERNEL); |
| if (!p) |
| return ERR_PTR(-EBUSY); |
| |
| p->dkstats = alloc_percpu(struct disk_stats); |
| if (!p->dkstats) { |
| err = -ENOMEM; |
| goto out_free; |
| } |
| |
| hd_sects_seq_init(p); |
| pdev = part_to_dev(p); |
| |
| p->start_sect = start; |
| p->alignment_offset = |
| queue_limit_alignment_offset(&disk->queue->limits, start); |
| p->discard_alignment = |
| queue_limit_discard_alignment(&disk->queue->limits, start); |
| p->nr_sects = len; |
| p->partno = partno; |
| p->policy = get_disk_ro(disk); |
| |
| if (info) { |
| struct partition_meta_info *pinfo; |
| |
| pinfo = kzalloc_node(sizeof(*pinfo), GFP_KERNEL, disk->node_id); |
| if (!pinfo) { |
| err = -ENOMEM; |
| goto out_free_stats; |
| } |
| memcpy(pinfo, info, sizeof(*info)); |
| p->info = pinfo; |
| } |
| |
| dname = dev_name(ddev); |
| if (isdigit(dname[strlen(dname) - 1])) |
| dev_set_name(pdev, "%sp%d", dname, partno); |
| else |
| dev_set_name(pdev, "%s%d", dname, partno); |
| |
| device_initialize(pdev); |
| pdev->class = &block_class; |
| pdev->type = &part_type; |
| pdev->parent = ddev; |
| |
| err = blk_alloc_devt(p, &devt); |
| if (err) |
| goto out_free_info; |
| pdev->devt = devt; |
| |
| /* delay uevent until 'holders' subdir is created */ |
| dev_set_uevent_suppress(pdev, 1); |
| err = device_add(pdev); |
| if (err) |
| goto out_put; |
| |
| err = -ENOMEM; |
| p->holder_dir = kobject_create_and_add("holders", &pdev->kobj); |
| if (!p->holder_dir) |
| goto out_del; |
| |
| dev_set_uevent_suppress(pdev, 0); |
| if (flags & ADDPART_FLAG_WHOLEDISK) { |
| err = device_create_file(pdev, &dev_attr_whole_disk); |
| if (err) |
| goto out_del; |
| } |
| |
| err = hd_ref_init(p); |
| if (err) { |
| if (flags & ADDPART_FLAG_WHOLEDISK) |
| goto out_remove_file; |
| goto out_del; |
| } |
| |
| /* everything is up and running, commence */ |
| rcu_assign_pointer(ptbl->part[partno], p); |
| |
| /* suppress uevent if the disk suppresses it */ |
| if (!dev_get_uevent_suppress(ddev)) |
| kobject_uevent(&pdev->kobj, KOBJ_ADD); |
| return p; |
| |
| out_free_info: |
| kfree(p->info); |
| out_free_stats: |
| free_percpu(p->dkstats); |
| out_free: |
| kfree(p); |
| return ERR_PTR(err); |
| out_remove_file: |
| device_remove_file(pdev, &dev_attr_whole_disk); |
| out_del: |
| kobject_put(p->holder_dir); |
| device_del(pdev); |
| out_put: |
| put_device(pdev); |
| return ERR_PTR(err); |
| } |
| |
| static bool partition_overlaps(struct gendisk *disk, sector_t start, |
| sector_t length, int skip_partno) |
| { |
| struct disk_part_iter piter; |
| struct hd_struct *part; |
| bool overlap = false; |
| |
| disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY); |
| while ((part = disk_part_iter_next(&piter))) { |
| if (part->partno == skip_partno || |
| start >= part->start_sect + part->nr_sects || |
| start + length <= part->start_sect) |
| continue; |
| overlap = true; |
| break; |
| } |
| |
| disk_part_iter_exit(&piter); |
| return overlap; |
| } |
| |
| int bdev_add_partition(struct block_device *bdev, int partno, |
| sector_t start, sector_t length) |
| { |
| struct hd_struct *part; |
| |
| mutex_lock(&bdev->bd_mutex); |
| if (partition_overlaps(bdev->bd_disk, start, length, -1)) { |
| mutex_unlock(&bdev->bd_mutex); |
| return -EBUSY; |
| } |
| |
| part = add_partition(bdev->bd_disk, partno, start, length, |
| ADDPART_FLAG_NONE, NULL); |
| mutex_unlock(&bdev->bd_mutex); |
| return PTR_ERR_OR_ZERO(part); |
| } |
| |
| int bdev_del_partition(struct block_device *bdev, int partno) |
| { |
| struct block_device *bdevp; |
| struct hd_struct *part; |
| int ret = 0; |
| |
| part = disk_get_part(bdev->bd_disk, partno); |
| if (!part) |
| return -ENXIO; |
| |
| ret = -ENOMEM; |
| bdevp = bdget(part_devt(part)); |
| if (!bdevp) |
| goto out_put_part; |
| |
| mutex_lock(&bdevp->bd_mutex); |
| |
| ret = -EBUSY; |
| if (bdevp->bd_openers) |
| goto out_unlock; |
| |
| sync_blockdev(bdevp); |
| invalidate_bdev(bdevp); |
| |
| mutex_lock_nested(&bdev->bd_mutex, 1); |
| delete_partition(bdev->bd_disk, part); |
| mutex_unlock(&bdev->bd_mutex); |
| |
| ret = 0; |
| out_unlock: |
| mutex_unlock(&bdevp->bd_mutex); |
| bdput(bdevp); |
| out_put_part: |
| disk_put_part(part); |
| return ret; |
| } |
| |
| int bdev_resize_partition(struct block_device *bdev, int partno, |
| sector_t start, sector_t length) |
| { |
| struct block_device *bdevp; |
| struct hd_struct *part; |
| int ret = 0; |
| |
| part = disk_get_part(bdev->bd_disk, partno); |
| if (!part) |
| return -ENXIO; |
| |
| ret = -ENOMEM; |
| bdevp = bdget(part_devt(part)); |
| if (!bdevp) |
| goto out_put_part; |
| |
| mutex_lock(&bdevp->bd_mutex); |
| mutex_lock_nested(&bdev->bd_mutex, 1); |
| |
| ret = -EINVAL; |
| if (start != part->start_sect) |
| goto out_unlock; |
| |
| ret = -EBUSY; |
| if (partition_overlaps(bdev->bd_disk, start, length, partno)) |
| goto out_unlock; |
| |
| part_nr_sects_write(part, (sector_t)length); |
| i_size_write(bdevp->bd_inode, length << SECTOR_SHIFT); |
| |
| ret = 0; |
| out_unlock: |
| mutex_unlock(&bdevp->bd_mutex); |
| mutex_unlock(&bdev->bd_mutex); |
| bdput(bdevp); |
| out_put_part: |
| disk_put_part(part); |
| return ret; |
| } |
| |
| static bool disk_unlock_native_capacity(struct gendisk *disk) |
| { |
| const struct block_device_operations *bdops = disk->fops; |
| |
| if (bdops->unlock_native_capacity && |
| !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) { |
| printk(KERN_CONT "enabling native capacity\n"); |
| bdops->unlock_native_capacity(disk); |
| disk->flags |= GENHD_FL_NATIVE_CAPACITY; |
| return true; |
| } else { |
| printk(KERN_CONT "truncated\n"); |
| return false; |
| } |
| } |
| |
| int blk_drop_partitions(struct block_device *bdev) |
| { |
| struct disk_part_iter piter; |
| struct hd_struct *part; |
| |
| if (!disk_part_scan_enabled(bdev->bd_disk)) |
| return 0; |
| if (bdev->bd_part_count) |
| return -EBUSY; |
| |
| sync_blockdev(bdev); |
| invalidate_bdev(bdev); |
| |
| disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY); |
| while ((part = disk_part_iter_next(&piter))) |
| delete_partition(bdev->bd_disk, part); |
| disk_part_iter_exit(&piter); |
| |
| return 0; |
| } |
| #ifdef CONFIG_S390 |
| /* for historic reasons in the DASD driver */ |
| EXPORT_SYMBOL_GPL(blk_drop_partitions); |
| #endif |
| |
| static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev, |
| struct parsed_partitions *state, int p) |
| { |
| sector_t size = state->parts[p].size; |
| sector_t from = state->parts[p].from; |
| struct hd_struct *part; |
| |
| if (!size) |
| return true; |
| |
| if (from >= get_capacity(disk)) { |
| printk(KERN_WARNING |
| "%s: p%d start %llu is beyond EOD, ", |
| disk->disk_name, p, (unsigned long long) from); |
| if (disk_unlock_native_capacity(disk)) |
| return false; |
| return true; |
| } |
| |
| if (from + size > get_capacity(disk)) { |
| printk(KERN_WARNING |
| "%s: p%d size %llu extends beyond EOD, ", |
| disk->disk_name, p, (unsigned long long) size); |
| |
| if (disk_unlock_native_capacity(disk)) |
| return false; |
| |
| /* |
| * We can not ignore partitions of broken tables created by for |
| * example camera firmware, but we limit them to the end of the |
| * disk to avoid creating invalid block devices. |
| */ |
| size = get_capacity(disk) - from; |
| } |
| |
| part = add_partition(disk, p, from, size, state->parts[p].flags, |
| &state->parts[p].info); |
| if (IS_ERR(part) && PTR_ERR(part) != -ENXIO) { |
| printk(KERN_ERR " %s: p%d could not be added: %ld\n", |
| disk->disk_name, p, -PTR_ERR(part)); |
| return true; |
| } |
| |
| if (IS_BUILTIN(CONFIG_BLK_DEV_MD) && |
| (state->parts[p].flags & ADDPART_FLAG_RAID)) |
| md_autodetect_dev(part_to_dev(part)->devt); |
| |
| return true; |
| } |
| |
| int blk_add_partitions(struct gendisk *disk, struct block_device *bdev) |
| { |
| struct parsed_partitions *state; |
| int ret = -EAGAIN, p, highest; |
| |
| if (!disk_part_scan_enabled(disk)) |
| return 0; |
| |
| state = check_partition(disk, bdev); |
| if (!state) |
| return 0; |
| if (IS_ERR(state)) { |
| /* |
| * I/O error reading the partition table. If we tried to read |
| * beyond EOD, retry after unlocking the native capacity. |
| */ |
| if (PTR_ERR(state) == -ENOSPC) { |
| printk(KERN_WARNING "%s: partition table beyond EOD, ", |
| disk->disk_name); |
| if (disk_unlock_native_capacity(disk)) |
| return -EAGAIN; |
| } |
| return -EIO; |
| } |
| |
| /* |
| * Partitions are not supported on host managed zoned block devices. |
| */ |
| if (disk->queue->limits.zoned == BLK_ZONED_HM) { |
| pr_warn("%s: ignoring partition table on host managed zoned block device\n", |
| disk->disk_name); |
| ret = 0; |
| goto out_free_state; |
| } |
| |
| /* |
| * If we read beyond EOD, try unlocking native capacity even if the |
| * partition table was successfully read as we could be missing some |
| * partitions. |
| */ |
| if (state->access_beyond_eod) { |
| printk(KERN_WARNING |
| "%s: partition table partially beyond EOD, ", |
| disk->disk_name); |
| if (disk_unlock_native_capacity(disk)) |
| goto out_free_state; |
| } |
| |
| /* tell userspace that the media / partition table may have changed */ |
| kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE); |
| |
| /* |
| * Detect the highest partition number and preallocate disk->part_tbl. |
| * This is an optimization and not strictly necessary. |
| */ |
| for (p = 1, highest = 0; p < state->limit; p++) |
| if (state->parts[p].size) |
| highest = p; |
| disk_expand_part_tbl(disk, highest); |
| |
| for (p = 1; p < state->limit; p++) |
| if (!blk_add_partition(disk, bdev, state, p)) |
| goto out_free_state; |
| |
| ret = 0; |
| out_free_state: |
| free_partitions(state); |
| return ret; |
| } |
| |
| void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p) |
| { |
| struct address_space *mapping = state->bdev->bd_inode->i_mapping; |
| struct page *page; |
| |
| if (n >= get_capacity(state->bdev->bd_disk)) { |
| state->access_beyond_eod = true; |
| return NULL; |
| } |
| |
| page = read_mapping_page(mapping, |
| (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL); |
| if (IS_ERR(page)) |
| goto out; |
| if (PageError(page)) |
| goto out_put_page; |
| |
| p->v = page; |
| return (unsigned char *)page_address(page) + |
| ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << SECTOR_SHIFT); |
| out_put_page: |
| put_page(page); |
| out: |
| p->v = NULL; |
| return NULL; |
| } |