block: make partition array dynamic
disk->__part used to be statically allocated to the maximum possible
number of partitions. This patch makes partition array allocation
dynamic. The added overhead is minimal as only real change is one
memory dereference changed to RCU one. This saves both a bit of
memory and cpu cycles iterating through unoccupied slots and makes
increasing partition limit easier.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index c90e1b4..ecf649c 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -113,6 +113,21 @@
#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 @@
* 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 @@
#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 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);