block: pass io_comp_batch to rq_end_io_fn callback

Add a third parameter 'const struct io_comp_batch *' to the rq_end_io_fn
callback signature. This allows end_io handlers to access the completion
batch context when requests are completed via blk_mq_end_request_batch().

The io_comp_batch is passed from blk_mq_end_request_batch(), while NULL
is passed from __blk_mq_end_request() and blk_mq_put_rq_ref() which don't
have batch context.

This infrastructure change enables drivers to detect whether they're
being called from a batched completion path (like iopoll) and access
additional context stored in the io_comp_batch.

Update all rq_end_io_fn implementations:
- block/blk-mq.c: blk_end_sync_rq
- block/blk-flush.c: flush_end_io, mq_flush_data_end_io
- drivers/nvme/host/ioctl.c: nvme_uring_cmd_end_io
- drivers/nvme/host/core.c: nvme_keep_alive_end_io
- drivers/nvme/host/pci.c: abort_endio, nvme_del_queue_end, nvme_del_cq_end
- drivers/nvme/target/passthru.c: nvmet_passthru_req_done
- drivers/scsi/scsi_error.c: eh_lock_door_done
- drivers/scsi/sg.c: sg_rq_end_io
- drivers/scsi/st.c: st_scsi_execute_end
- drivers/target/target_core_pscsi.c: pscsi_req_done
- drivers/md/dm-rq.c: end_clone_request

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 2 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 43d6152897a4..403a46c86411 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -199,7 +199,8 @@ static void blk_flush_complete_seq(struct request *rq,
 }
 
 static enum rq_end_io_ret flush_end_io(struct request *flush_rq,
-				       blk_status_t error)
+				       blk_status_t error,
+				       const struct io_comp_batch *iob)
 {
 	struct request_queue *q = flush_rq->q;
 	struct list_head *running;
@@ -335,7 +336,8 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 }
 
 static enum rq_end_io_ret mq_flush_data_end_io(struct request *rq,
-					       blk_status_t error)
+					       blk_status_t error,
+					       const struct io_comp_batch *iob)
 {
 	struct request_queue *q = rq->q;
 	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;