[RFC PATCH 1/4] block: introduce async ioctl operation

[Kanchan Joshi]

Add a new block-dev operation for async-ioctl.
Driver managing the block-dev can choose to implement it.

Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
---
 include/linux/blkdev.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f94ee3089e01..c9f6cc26d675 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1848,6 +1848,16 @@ static inline void blk_ksm_unregister(struct request_queue *q) { }
 
 #endif /* CONFIG_BLK_INLINE_ENCRYPTION */
 
+struct pt_ioctl_ctx {
+	/* submitter task context */
+	struct task_struct *task;
+	/* callback supplied by upper layer */
+	void (*pt_complete)(struct pt_ioctl_ctx *ptioc, long ret);
+	/* driver-allocated data */
+	void *ioc_data;
+	/* to schedule task-work */
+	struct callback_head pt_work;
+};
 
 struct block_device_operations {
 	blk_qc_t (*submit_bio) (struct bio *bio);
@@ -1856,6 +1866,8 @@ struct block_device_operations {
 	int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int);
 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
+	int (*async_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long,
+				struct pt_ioctl_ctx *);
 	unsigned int (*check_events) (struct gendisk *disk,
 				      unsigned int clearing);
 	void (*unlock_native_capacity) (struct gendisk *);
-- 
2.25.1