diff options
| -rw-r--r-- | block/genhd.c | 23 | ||||
| -rw-r--r-- | include/linux/genhd.h | 1 |
2 files changed, 20 insertions, 4 deletions
diff --git a/block/genhd.c b/block/genhd.c index 2f7feda61e35..d84a7df1e2a0 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -181,6 +181,12 @@ void disk_part_iter_exit(struct disk_part_iter *piter) } EXPORT_SYMBOL_GPL(disk_part_iter_exit); +static inline int sector_in_part(struct hd_struct *part, sector_t sector) +{ + return part->start_sect <= sector && + sector < part->start_sect + part->nr_sects; +} + /** * disk_map_sector_rcu - map sector to partition * @disk: gendisk of interest @@ -199,16 +205,22 @@ 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; + struct hd_struct *part; int i; ptbl = rcu_dereference(disk->part_tbl); + part = rcu_dereference(ptbl->last_lookup); + if (part && sector_in_part(part, sector)) + return part; + for (i = 1; i < ptbl->len; i++) { - struct hd_struct *part = rcu_dereference(ptbl->part[i]); + part = rcu_dereference(ptbl->part[i]); - if (part && part->start_sect <= sector && - sector < part->start_sect + part->nr_sects) + if (part && sector_in_part(part, sector)) { + rcu_assign_pointer(ptbl->last_lookup, part); return part; + } } return &disk->part0; } @@ -888,8 +900,11 @@ static void disk_replace_part_tbl(struct gendisk *disk, struct disk_part_tbl *old_ptbl = disk->part_tbl; rcu_assign_pointer(disk->part_tbl, new_ptbl); - if (old_ptbl) + + if (old_ptbl) { + rcu_assign_pointer(old_ptbl->last_lookup, NULL); call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb); + } } /** diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 3df7742ce246..16948eaecae3 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -126,6 +126,7 @@ struct blk_scsi_cmd_filter { struct disk_part_tbl { struct rcu_head rcu_head; int len; + struct hd_struct *last_lookup; struct hd_struct *part[]; }; |