Add support to allocate and free a multipath gendisk. NVMe has almost like-for-like equivalents here: - mpath_alloc_head_disk() -> nvme_mpath_alloc_disk() - multipath_partition_scan_work() -> nvme_partition_scan_work() - mpath_remove_disk() -> nvme_remove_head() - mpath_device_set_live() -> nvme_mpath_set_live()
struct mpath_head_template is introduced as a method for drivers to provide custom multipath functionality. Signed-off-by: John Garry <[email protected]> --- include/linux/multipath.h | 38 ++++++++++++++++ lib/multipath.c | 96 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 134 insertions(+) diff --git a/include/linux/multipath.h b/include/linux/multipath.h index 102dfcf21ffc9..3e2a513059cde 100644 --- a/include/linux/multipath.h +++ b/include/linux/multipath.h @@ -5,11 +5,19 @@ #include <linux/blkdev.h> #include <linux/srcu.h> +extern const struct block_device_operations mpath_ops; + struct mpath_device { + struct mpath_head *mpath_head; struct list_head siblings; struct gendisk *disk; }; +struct mpath_head_template { +}; + +#define MPATH_HEAD_DISK_LIVE 0 + struct mpath_head { struct srcu_struct srcu; struct list_head dev_list; /* list of all mpath_devs */ @@ -18,11 +26,41 @@ struct mpath_head { struct kref ref; void *drvdata; + unsigned long flags; + struct gendisk *disk; + struct work_struct partition_scan_work; + struct device *parent; + const struct attribute_group **disk_groups; + const struct mpath_head_template *mpdt; struct mpath_device __rcu *current_path[]; }; +static inline struct mpath_head *mpath_bd_device_to_head(struct device *dev) +{ + return dev_get_drvdata(dev); +} + +static inline struct mpath_head *mpath_gendisk_to_head(struct gendisk *disk) +{ + return mpath_bd_device_to_head(disk_to_dev(disk)); +} + int mpath_get_head(struct mpath_head *mpath_head); void mpath_put_head(struct mpath_head *mpath_head); struct mpath_head *mpath_alloc_head(void); +void mpath_put_disk(struct mpath_head *mpath_head); +void mpath_remove_disk(struct mpath_head *mpath_head); +int mpath_alloc_head_disk(struct mpath_head *mpath_head, + struct queue_limits *lim, int numa_node); +void mpath_device_set_live(struct mpath_device *mpath_device); + +static inline bool is_mpath_disk(struct gendisk *disk) +{ + #if IS_ENABLED(CONFIG_LIBMULTIPATH) + return disk->fops == &mpath_ops; + #else + return false; + #endif +} #endif // _LIBMULTIPATH_H diff --git a/lib/multipath.c b/lib/multipath.c index 0d5690b5ba4ca..726d9bec13553 100644 --- a/lib/multipath.c +++ b/lib/multipath.c @@ -31,6 +31,99 @@ void mpath_put_head(struct mpath_head *mpath_head) } EXPORT_SYMBOL_GPL(mpath_put_head); +static int mpath_bdev_open(struct gendisk *disk, blk_mode_t mode) +{ + struct mpath_head *mpath_head = disk->private_data; + + return mpath_get_head(mpath_head); +} + +static void mpath_bdev_release(struct gendisk *disk) +{ + struct mpath_head *mpath_head = disk->private_data; + + mpath_put_head(mpath_head); +} + +const struct block_device_operations mpath_ops = { + .owner = THIS_MODULE, + .open = mpath_bdev_open, + .release = mpath_bdev_release, +}; +EXPORT_SYMBOL_GPL(mpath_ops); + +static void multipath_partition_scan_work(struct work_struct *work) +{ + struct mpath_head *mpath_head = + container_of(work, struct mpath_head, partition_scan_work); + + if (WARN_ON_ONCE(!test_and_clear_bit(GD_SUPPRESS_PART_SCAN, + &mpath_head->disk->state))) + return; + + mutex_lock(&mpath_head->disk->open_mutex); + bdev_disk_changed(mpath_head->disk, false); + mutex_unlock(&mpath_head->disk->open_mutex); +} + +void mpath_remove_disk(struct mpath_head *mpath_head) +{ + if (test_and_clear_bit(MPATH_HEAD_DISK_LIVE, &mpath_head->flags)) { + struct gendisk *disk = mpath_head->disk; + + del_gendisk(disk); + } +} +EXPORT_SYMBOL_GPL(mpath_remove_disk); + +void mpath_put_disk(struct mpath_head *mpath_head) +{ + if (!mpath_head->disk) + return; + + /* make sure all pending bios are cleaned up */ + flush_work(&mpath_head->partition_scan_work); + put_disk(mpath_head->disk); +} +EXPORT_SYMBOL_GPL(mpath_put_disk); + +int mpath_alloc_head_disk(struct mpath_head *mpath_head, + struct queue_limits *lim, int numa_node) +{ + mpath_head->disk = blk_alloc_disk(lim, numa_node); + if (IS_ERR(mpath_head->disk)) + return PTR_ERR(mpath_head->disk); + + mpath_head->disk->private_data = mpath_head; + mpath_head->disk->fops = &mpath_ops; + + set_bit(GD_SUPPRESS_PART_SCAN, &mpath_head->disk->state); + + return 0; +} +EXPORT_SYMBOL_GPL(mpath_alloc_head_disk); + +void mpath_device_set_live(struct mpath_device *mpath_device) +{ + struct mpath_head *mpath_head = mpath_device->mpath_head; + int ret; + + if (!mpath_head->disk) + return; + + if (!test_and_set_bit(MPATH_HEAD_DISK_LIVE, &mpath_head->flags)) { + dev_set_drvdata(disk_to_dev(mpath_head->disk), mpath_head); + ret = device_add_disk(mpath_head->parent, mpath_head->disk, + mpath_head->disk_groups); + if (ret) { + clear_bit(MPATH_HEAD_DISK_LIVE, &mpath_head->flags); + return; + } + queue_work(mpath_wq, &mpath_head->partition_scan_work); + } +} +EXPORT_SYMBOL_GPL(mpath_device_set_live); + struct mpath_head *mpath_alloc_head(void) { struct mpath_head *mpath_head; @@ -44,6 +137,9 @@ struct mpath_head *mpath_alloc_head(void) mutex_init(&mpath_head->lock); kref_init(&mpath_head->ref); + INIT_WORK(&mpath_head->partition_scan_work, + multipath_partition_scan_work); + ret = init_srcu_struct(&mpath_head->srcu); if (ret) { kfree(mpath_head); -- 2.43.5
