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>

2 files changed, 9 insertions, 6 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;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a29d8ac9d3e3..cf1daedbb39f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1156,7 +1156,7 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
 
 	if (rq->end_io) {
 		rq_qos_done(rq->q, rq);
-		if (rq->end_io(rq, error) == RQ_END_IO_FREE)
+		if (rq->end_io(rq, error, NULL) == RQ_END_IO_FREE)
 			blk_mq_free_request(rq);
 	} else {
 		blk_mq_free_request(rq);
@@ -1211,7 +1211,7 @@ void blk_mq_end_request_batch(struct io_comp_batch *iob)
 		 * If end_io handler returns NONE, then it still has
 		 * ownership of the request.
 		 */
-		if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
+		if (rq->end_io && rq->end_io(rq, 0, iob) == RQ_END_IO_NONE)
 			continue;
 
 		WRITE_ONCE(rq->state, MQ_RQ_IDLE);
@@ -1458,7 +1458,8 @@ struct blk_rq_wait {
 	blk_status_t ret;
 };
 
-static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
+static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret,
+					  const struct io_comp_batch *iob)
 {
 	struct blk_rq_wait *wait = rq->end_io_data;
 
@@ -1688,7 +1689,7 @@ static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expi
 void blk_mq_put_rq_ref(struct request *rq)
 {
 	if (is_flush_rq(rq)) {
-		if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
+		if (rq->end_io(rq, 0, NULL) == RQ_END_IO_FREE)
 			blk_mq_free_request(rq);
 	} else if (req_ref_put_and_test(rq)) {
 		__blk_mq_free_request(rq);