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, 2 insertions, 1 deletions

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index a6ca92049c10..e9a7563b4b2f 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -295,7 +295,8 @@ static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
 }
 
 static enum rq_end_io_ret end_clone_request(struct request *clone,
-					    blk_status_t error)
+					    blk_status_t error,
+					    const struct io_comp_batch *iob)
 {
 	struct dm_rq_target_io *tio = clone->end_io_data;