diff --git a/block/genhd.c b/block/genhd.c index e1cb96fb883e5908e3c69587a371a590110884b8..c2b14aa69d582961ee8c0b1147396632afdae81c 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -52,14 +52,21 @@ static struct device_type disk_type; */ struct hd_struct *disk_get_part(struct gendisk *disk, int partno) { - struct hd_struct *part; + struct hd_struct *part = NULL; + struct disk_part_tbl *ptbl; - if (unlikely(partno < 0 || partno >= disk_max_parts(disk))) + if (unlikely(partno < 0)) return NULL; + rcu_read_lock(); - part = rcu_dereference(disk->__part[partno]); - if (part) - get_device(part_to_dev(part)); + + ptbl = rcu_dereference(disk->part_tbl); + if (likely(partno < ptbl->len)) { + part = rcu_dereference(ptbl->part[partno]); + if (part) + get_device(part_to_dev(part)); + } + rcu_read_unlock(); return part; @@ -80,17 +87,24 @@ EXPORT_SYMBOL_GPL(disk_get_part); void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk, unsigned int flags) { + struct disk_part_tbl *ptbl; + + rcu_read_lock(); + ptbl = rcu_dereference(disk->part_tbl); + piter->disk = disk; piter->part = NULL; if (flags & DISK_PITER_REVERSE) - piter->idx = disk_max_parts(piter->disk) - 1; + piter->idx = ptbl->len - 1; else if (flags & DISK_PITER_INCL_PART0) piter->idx = 0; else piter->idx = 1; piter->flags = flags; + + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(disk_part_iter_init); @@ -105,13 +119,16 @@ EXPORT_SYMBOL_GPL(disk_part_iter_init); */ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) { + struct disk_part_tbl *ptbl; int inc, end; /* put the last partition */ disk_put_part(piter->part); piter->part = NULL; + /* get part_tbl */ rcu_read_lock(); + ptbl = rcu_dereference(piter->disk->part_tbl); /* determine iteration parameters */ if (piter->flags & DISK_PITER_REVERSE) { @@ -122,14 +139,14 @@ struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter) end = 0; } else { inc = 1; - end = disk_max_parts(piter->disk); + end = ptbl->len; } /* iterate to the next partition */ for (; piter->idx != end; piter->idx += inc) { struct hd_struct *part; - part = rcu_dereference(piter->disk->__part[piter->idx]); + part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects) @@ -180,10 +197,13 @@ EXPORT_SYMBOL_GPL(disk_part_iter_exit); */ struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector) { + struct disk_part_tbl *ptbl; int i; - for (i = 1; i < disk_max_parts(disk); i++) { - struct hd_struct *part = rcu_dereference(disk->__part[i]); + ptbl = rcu_dereference(disk->part_tbl); + + for (i = 1; i < ptbl->len; i++) { + struct hd_struct *part = rcu_dereference(ptbl->part[i]); if (part && part->start_sect <= sector && sector < part->start_sect + part->nr_sects) @@ -798,12 +818,86 @@ static struct attribute_group *disk_attr_groups[] = { NULL }; +static void disk_free_ptbl_rcu_cb(struct rcu_head *head) +{ + struct disk_part_tbl *ptbl = + container_of(head, struct disk_part_tbl, rcu_head); + + kfree(ptbl); +} + +/** + * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way + * @disk: disk to replace part_tbl for + * @new_ptbl: new part_tbl to install + * + * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The + * original ptbl is freed using RCU callback. + * + * LOCKING: + * Matching bd_mutx locked. + */ +static void disk_replace_part_tbl(struct gendisk *disk, + struct disk_part_tbl *new_ptbl) +{ + struct disk_part_tbl *old_ptbl = disk->part_tbl; + + rcu_assign_pointer(disk->part_tbl, new_ptbl); + if (old_ptbl) + call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb); +} + +/** + * disk_expand_part_tbl - expand disk->part_tbl + * @disk: disk to expand part_tbl for + * @partno: expand such that this partno can fit in + * + * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl + * uses RCU to allow unlocked dereferencing for stats and other stuff. + * + * LOCKING: + * Matching bd_mutex locked, might sleep. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +int disk_expand_part_tbl(struct gendisk *disk, int partno) +{ + struct disk_part_tbl *old_ptbl = disk->part_tbl; + struct disk_part_tbl *new_ptbl; + int len = old_ptbl ? old_ptbl->len : 0; + int target = partno + 1; + size_t size; + int i; + + /* disk_max_parts() is zero during initialization, ignore if so */ + if (disk_max_parts(disk) && target > disk_max_parts(disk)) + return -EINVAL; + + if (target <= len) + return 0; + + size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]); + new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id); + if (!new_ptbl) + return -ENOMEM; + + INIT_RCU_HEAD(&new_ptbl->rcu_head); + new_ptbl->len = target; + + for (i = 0; i < len; i++) + rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]); + + disk_replace_part_tbl(disk, new_ptbl); + return 0; +} + static void disk_release(struct device *dev) { struct gendisk *disk = dev_to_disk(dev); kfree(disk->random); - kfree(disk->__part); + disk_replace_part_tbl(disk, NULL); free_part_stats(&disk->part0); kfree(disk); } @@ -948,22 +1042,16 @@ struct gendisk *alloc_disk_ext_node(int minors, int ext_minors, int node_id) disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL | __GFP_ZERO, node_id); if (disk) { - int tot_minors = minors + ext_minors; - int size = tot_minors * sizeof(struct hd_struct *); - if (!init_part_stats(&disk->part0)) { kfree(disk); return NULL; } - - disk->__part = kmalloc_node(size, GFP_KERNEL | __GFP_ZERO, - node_id); - if (!disk->__part) { - free_part_stats(&disk->part0); + if (disk_expand_part_tbl(disk, 0)) { + free_part_stats(&disk->part0); kfree(disk); return NULL; } - disk->__part[0] = &disk->part0; + disk->part_tbl->part[0] = &disk->part0; disk->minors = minors; disk->ext_minors = ext_minors; @@ -973,6 +1061,7 @@ struct gendisk *alloc_disk_ext_node(int minors, int ext_minors, int node_id) device_initialize(disk_to_dev(disk)); INIT_WORK(&disk->async_notify, media_change_notify_thread); + disk->node_id = node_id; } return disk; } diff --git a/block/ioctl.c b/block/ioctl.c index 64e7c67a64b01fa9c733bc84d3de6579bd90955c..38bee321e1fa07c7dd41940c6fae8094a822068c 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -30,7 +30,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user if (bdev != bdev->bd_contains) return -EINVAL; partno = p.pno; - if (partno <= 0 || partno >= disk_max_parts(disk)) + if (partno <= 0) return -EINVAL; switch (a.op) { case BLKPG_ADD_PARTITION: diff --git a/fs/partitions/check.c b/fs/partitions/check.c index f517869e8d10a7eee08c7c490d4fd49bf9157aa6..772b2ed8d239ae1edf17456cee0a2b75b8bc66a0 100644 --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -312,14 +312,18 @@ static void delete_partition_rcu_cb(struct rcu_head *head) void delete_partition(struct gendisk *disk, int partno) { + struct disk_part_tbl *ptbl = disk->part_tbl; struct hd_struct *part; - part = disk->__part[partno]; + if (partno >= ptbl->len) + return; + + part = ptbl->part[partno]; if (!part) return; blk_free_devt(part_devt(part)); - rcu_assign_pointer(disk->__part[partno], NULL); + rcu_assign_pointer(ptbl->part[partno], NULL); kobject_put(part->holder_dir); device_del(part_to_dev(part)); @@ -341,10 +345,16 @@ int add_partition(struct gendisk *disk, int partno, 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; - if (disk->__part[partno]) + err = disk_expand_part_tbl(disk, partno); + if (err) + return err; + ptbl = disk->part_tbl; + + if (ptbl->part[partno]) return -EBUSY; p = kzalloc(sizeof(*p), GFP_KERNEL); @@ -398,7 +408,7 @@ int add_partition(struct gendisk *disk, int partno, /* everything is up and running, commence */ INIT_RCU_HEAD(&p->rcu_head); - rcu_assign_pointer(disk->__part[partno], p); + rcu_assign_pointer(ptbl->part[partno], p); /* suppress uevent if the disk supresses it */ if (!ddev->uevent_suppress) @@ -487,7 +497,7 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev) struct disk_part_iter piter; struct hd_struct *part; struct parsed_partitions *state; - int p, res; + int p, highest, res; if (bdev->bd_part_count) return -EBUSY; @@ -511,6 +521,17 @@ int rescan_partitions(struct gendisk *disk, struct block_device *bdev) /* 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); + + /* add partitions */ for (p = 1; p < state->limit; p++) { sector_t size = state->parts[p].size; sector_t from = state->parts[p].from; diff --git a/include/linux/genhd.h b/include/linux/genhd.h index c90e1b4fbe5a916671faae4a9309e8e27de787d1..ecf649c3deed4e19d47b6060f706cf08f149ae3b 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -113,6 +113,21 @@ struct hd_struct { #define GENHD_FL_UP 16 #define GENHD_FL_SUPPRESS_PARTITION_INFO 32 +#define BLK_SCSI_MAX_CMDS (256) +#define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) + +struct blk_scsi_cmd_filter { + unsigned long read_ok[BLK_SCSI_CMD_PER_LONG]; + unsigned long write_ok[BLK_SCSI_CMD_PER_LONG]; + struct kobject kobj; +}; + +struct disk_part_tbl { + struct rcu_head rcu_head; + int len; + struct hd_struct *part[]; +}; + struct gendisk { /* major, first_minor, minors and ext_minors are input * parameters only, don't use directly. Use disk_devt() and @@ -131,7 +146,7 @@ struct gendisk { * non-critical accesses use RCU. Always access through * helpers. */ - struct hd_struct **__part; + struct disk_part_tbl *part_tbl; struct hd_struct part0; struct block_device_operations *fops; @@ -149,6 +164,7 @@ struct gendisk { #ifdef CONFIG_BLK_DEV_INTEGRITY struct blk_integrity *integrity; #endif + int node_id; }; static inline struct gendisk *part_to_disk(struct hd_struct *part) @@ -503,6 +519,7 @@ 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); +extern int disk_expand_part_tbl(struct gendisk *disk, int target); extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev); extern int __must_check add_partition(struct gendisk *, int, sector_t, sector_t, int); extern void delete_partition(struct gendisk *, int);