Replace bd_partno with a 32bit field (__bd_flags). The lower 8 bits
contain the partition number, the upper 24 are for flags.
Helpers: bdev_{test,set,clear}_flag(bdev, flag), with atomic_or()
and atomic_andnot() used to set/clear.
NOTE: this commit does not actually move any flags over there - they
are still bool fields. As the result, it shifts the fields wrt
cacheline boundaries; that's going to be restored once the first
3 flags are dealt with.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
block/bdev.c | 2 +-
include/linux/blk_types.h | 3 ++-
include/linux/blkdev.h | 17 ++++++++++++++++-
3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/block/bdev.c b/block/bdev.c
index 7a5f611c3d2e..2ec223315500 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -411,7 +411,7 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
mutex_init(&bdev->bd_fsfreeze_mutex);
spin_lock_init(&bdev->bd_size_lock);
mutex_init(&bdev->bd_holder_lock);
- bdev->bd_partno = partno;
+ atomic_set(&bdev->__bd_flags, partno);
bdev->bd_inode = inode;
bdev->bd_queue = disk->queue;
if (partno)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index cb1526ec44b5..04f92737ab08 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -45,8 +45,9 @@ struct block_device {
struct request_queue * bd_queue;
struct disk_stats __percpu *bd_stats;
unsigned long bd_stamp;
+ atomic_t __bd_flags; // partition number + flags
+#define BD_PARTNO 255 // lower 8 bits; assign-once
bool bd_read_only; /* read-only policy */
- u8 bd_partno;
bool bd_write_holder;
bool bd_has_submit_bio;
dev_t bd_dev;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 32549d675955..99917e5860fd 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -722,7 +722,22 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action);
static inline u8 bdev_partno(const struct block_device *bdev)
{
- return bdev->bd_partno;
+ return atomic_read(&bdev->__bd_flags) & BD_PARTNO;
+}
+
+static inline bool bdev_test_flag(const struct block_device *bdev, unsigned flag)
+{
+ return atomic_read(&bdev->__bd_flags) & flag;
+}
+
+static inline void bdev_set_flag(struct block_device *bdev, unsigned flag)
+{
+ atomic_or(flag, &bdev->__bd_flags);
+}
+
+static inline void bdev_clear_flag(struct block_device *bdev, unsigned flag)
+{
+ atomic_andnot(flag, &bdev->__bd_flags);
}
static inline int get_disk_ro(struct gendisk *disk)
--
2.39.2
