block: change request end_io handler to pass back a return value

Everything is just converted to returning RQ_END_IO_NONE, and there
should be no functional changes with this patch.

In preparation for allowing the end_io handler to pass ownership back
to the block layer, rather than retain ownership of the request.

Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-flush.c

@@ -217,7 +217,8 @@ static void blk_flush_complete_seq(struct request *rq,
 	blk_kick_flush(q, fq, cmd_flags);
 }
 
-static void flush_end_io(struct request *flush_rq, blk_status_t error)
+static enum rq_end_io_ret flush_end_io(struct request *flush_rq,
+				       blk_status_t error)
 {
 	struct request_queue *q = flush_rq->q;
 	struct list_head *running;
@@ -231,7 +232,7 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	if (!req_ref_put_and_test(flush_rq)) {
 		fq->rq_status = error;
 		spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
-		return;
+		return RQ_END_IO_NONE;
 	}
 
 	blk_account_io_flush(flush_rq);
@@ -268,6 +269,7 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 	}
 
 	spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
+	return RQ_END_IO_NONE;
 }
 
 bool is_flush_rq(struct request *rq)
@@ -353,7 +355,8 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
 	blk_flush_queue_rq(flush_rq, false);
 }
 
-static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
+static enum rq_end_io_ret mq_flush_data_end_io(struct request *rq,
+					       blk_status_t error)
 {
 	struct request_queue *q = rq->q;
 	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
@@ -375,6 +378,7 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
 	spin_unlock_irqrestore(&fq->mq_flush_lock, flags);
 
 	blk_mq_sched_restart(hctx);
+	return RQ_END_IO_NONE;
 }
 
 /**

block/blk-mq.c

@@ -1001,7 +1001,8 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
 
 	if (rq->end_io) {
 		rq_qos_done(rq->q, rq);
-		rq->end_io(rq, error);
+		if (rq->end_io(rq, error) == RQ_END_IO_FREE)
+			blk_mq_free_request(rq);
 	} else {
 		blk_mq_free_request(rq);
 	}
@@ -1295,12 +1296,13 @@ struct blk_rq_wait {
 	blk_status_t ret;
 };
 
-static void 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)
 {
 	struct blk_rq_wait *wait = rq->end_io_data;
 
 	wait->ret = ret;
 	complete(&wait->done);
+	return RQ_END_IO_NONE;
 }
 
 bool blk_rq_is_poll(struct request *rq)
@@ -1534,10 +1536,12 @@ static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
 
 void blk_mq_put_rq_ref(struct request *rq)
 {
-	if (is_flush_rq(rq))
-		rq->end_io(rq, 0);
-	else if (req_ref_put_and_test(rq))
+	if (is_flush_rq(rq)) {
+		if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
+			blk_mq_free_request(rq);
+	} else if (req_ref_put_and_test(rq)) {
 		__blk_mq_free_request(rq);
+	}
 }
 
 static bool blk_mq_check_expired(struct request *rq, void *priv)

drivers/md/dm-rq.c

@@ -292,11 +292,13 @@ static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
 	dm_complete_request(rq, error);
 }
 
-static void end_clone_request(struct request *clone, blk_status_t error)
+static enum rq_end_io_ret end_clone_request(struct request *clone,
+					    blk_status_t error)
 {
 	struct dm_rq_target_io *tio = clone->end_io_data;
 
 	dm_complete_request(tio->orig, error);
+	return RQ_END_IO_NONE;
 }
 
 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,

drivers/nvme/host/core.c

@@ -1172,7 +1172,8 @@ static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl)
 	queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2);
 }
 
-static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
+static enum rq_end_io_ret nvme_keep_alive_end_io(struct request *rq,
+						 blk_status_t status)
 {
 	struct nvme_ctrl *ctrl = rq->end_io_data;
 	unsigned long flags;
@@ -1184,7 +1185,7 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
 		dev_err(ctrl->device,
 			"failed nvme_keep_alive_end_io error=%d\n",
 				status);
-		return;
+		return RQ_END_IO_NONE;
 	}
 
 	ctrl->comp_seen = false;
@@ -1195,6 +1196,7 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)
 	spin_unlock_irqrestore(&ctrl->lock, flags);
 	if (startka)
 		nvme_queue_keep_alive_work(ctrl);
+	return RQ_END_IO_NONE;
 }
 
 static void nvme_keep_alive_work(struct work_struct *work)

drivers/nvme/host/ioctl.c

@@ -392,7 +392,8 @@ static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd)
 	io_uring_cmd_done(ioucmd, status, result);
 }
 
-static void nvme_uring_cmd_end_io(struct request *req, blk_status_t err)
+static enum rq_end_io_ret nvme_uring_cmd_end_io(struct request *req,
+						blk_status_t err)
 {
 	struct io_uring_cmd *ioucmd = req->end_io_data;
 	struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
@@ -411,6 +412,8 @@ static void nvme_uring_cmd_end_io(struct request *req, blk_status_t err)
 		nvme_uring_task_cb(ioucmd);
 	else
 		io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
+
+	return RQ_END_IO_NONE;
 }
 
 static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,

drivers/nvme/host/pci.c

@@ -1268,7 +1268,7 @@ static int adapter_delete_sq(struct nvme_dev *dev, u16 sqid)
 	return adapter_delete_queue(dev, nvme_admin_delete_sq, sqid);
 }
 
-static void abort_endio(struct request *req, blk_status_t error)
+static enum rq_end_io_ret abort_endio(struct request *req, blk_status_t error)
 {
 	struct nvme_queue *nvmeq = req->mq_hctx->driver_data;
 
@@ -1276,6 +1276,7 @@ static void abort_endio(struct request *req, blk_status_t error)
 		 "Abort status: 0x%x", nvme_req(req)->status);
 	atomic_inc(&nvmeq->dev->ctrl.abort_limit);
 	blk_mq_free_request(req);
+	return RQ_END_IO_NONE;
 }
 
 static bool nvme_should_reset(struct nvme_dev *dev, u32 csts)
@@ -2447,22 +2448,25 @@ out_unlock:
 	return result;
 }
 
-static void nvme_del_queue_end(struct request *req, blk_status_t error)
+static enum rq_end_io_ret nvme_del_queue_end(struct request *req,
+					     blk_status_t error)
 {
 	struct nvme_queue *nvmeq = req->end_io_data;
 
 	blk_mq_free_request(req);
 	complete(&nvmeq->delete_done);
+	return RQ_END_IO_NONE;
 }
 
-static void nvme_del_cq_end(struct request *req, blk_status_t error)
+static enum rq_end_io_ret nvme_del_cq_end(struct request *req,
+					  blk_status_t error)
 {
 	struct nvme_queue *nvmeq = req->end_io_data;
 
 	if (error)
 		set_bit(NVMEQ_DELETE_ERROR, &nvmeq->flags);
 
-	nvme_del_queue_end(req, error);
+	return nvme_del_queue_end(req, error);
 }
 
 static int nvme_delete_queue(struct nvme_queue *nvmeq, u8 opcode)

drivers/nvme/target/passthru.c

@@ -245,14 +245,15 @@ static void nvmet_passthru_execute_cmd_work(struct work_struct *w)
 		nvme_passthru_end(ctrl, effects, req->cmd, status);
 }
 
-static void nvmet_passthru_req_done(struct request *rq,
-				    blk_status_t blk_status)
+static enum rq_end_io_ret nvmet_passthru_req_done(struct request *rq,
+						  blk_status_t blk_status)
 {
 	struct nvmet_req *req = rq->end_io_data;
 
 	req->cqe->result = nvme_req(rq)->result;
 	nvmet_req_complete(req, nvme_req(rq)->status);
 	blk_mq_free_request(rq);
+	return RQ_END_IO_NONE;
 }
 
 static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)

drivers/scsi/scsi_error.c

@@ -2004,9 +2004,11 @@ maybe_retry:
 	}
 }
 
-static void eh_lock_door_done(struct request *req, blk_status_t status)
+static enum rq_end_io_ret eh_lock_door_done(struct request *req,
+					    blk_status_t status)
 {
 	blk_mq_free_request(req);
+	return RQ_END_IO_NONE;
 }
 
 /**

drivers/scsi/sg.c

@@ -177,7 +177,7 @@ typedef struct sg_device { /* holds the state of each scsi generic device */
 } Sg_device;
 
 /* tasklet or soft irq callback */
-static void sg_rq_end_io(struct request *rq, blk_status_t status);
+static enum rq_end_io_ret sg_rq_end_io(struct request *rq, blk_status_t status);
 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
 static int sg_finish_rem_req(Sg_request * srp);
 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
@@ -1311,7 +1311,7 @@ sg_rq_end_io_usercontext(struct work_struct *work)
  * This function is a "bottom half" handler that is called by the mid
  * level when a command is completed (or has failed).
  */
-static void
+static enum rq_end_io_ret
 sg_rq_end_io(struct request *rq, blk_status_t status)
 {
 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
@@ -1324,11 +1324,11 @@ sg_rq_end_io(struct request *rq, blk_status_t status)
 	int result, resid, done = 1;
 
 	if (WARN_ON(srp->done != 0))
-		return;
+		return RQ_END_IO_NONE;
 
 	sfp = srp->parentfp;
 	if (WARN_ON(sfp == NULL))
-		return;
+		return RQ_END_IO_NONE;
 
 	sdp = sfp->parentdp;
 	if (unlikely(atomic_read(&sdp->detaching)))
@@ -1406,6 +1406,7 @@ sg_rq_end_io(struct request *rq, blk_status_t status)
 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
 		schedule_work(&srp->ew.work);
 	}
+	return RQ_END_IO_NONE;
 }
 
 static const struct file_operations sg_fops = {

drivers/scsi/st.c

@@ -512,7 +512,8 @@ static void st_do_stats(struct scsi_tape *STp, struct request *req)
 	atomic64_dec(&STp->stats->in_flight);
 }
 
-static void st_scsi_execute_end(struct request *req, blk_status_t status)
+static enum rq_end_io_ret st_scsi_execute_end(struct request *req,
+					      blk_status_t status)
 {
 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
 	struct st_request *SRpnt = req->end_io_data;
@@ -532,6 +533,7 @@ static void st_scsi_execute_end(struct request *req, blk_status_t status)
 
 	blk_rq_unmap_user(tmp);
 	blk_mq_free_request(req);
+	return RQ_END_IO_NONE;
 }
 
 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,

drivers/target/target_core_pscsi.c

@@ -39,7 +39,7 @@ static inline struct pscsi_dev_virt *PSCSI_DEV(struct se_device *dev)
 }
 
 static sense_reason_t pscsi_execute_cmd(struct se_cmd *cmd);
-static void pscsi_req_done(struct request *, blk_status_t);
+static enum rq_end_io_ret pscsi_req_done(struct request *, blk_status_t);
 
 /*	pscsi_attach_hba():
  *
@@ -1002,7 +1002,8 @@ static sector_t pscsi_get_blocks(struct se_device *dev)
 	return 0;
 }
 
-static void pscsi_req_done(struct request *req, blk_status_t status)
+static enum rq_end_io_ret pscsi_req_done(struct request *req,
+					 blk_status_t status)
 {
 	struct se_cmd *cmd = req->end_io_data;
 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
@@ -1029,6 +1030,7 @@ static void pscsi_req_done(struct request *req, blk_status_t status)
 	}
 
 	blk_mq_free_request(req);
+	return RQ_END_IO_NONE;
 }
 
 static const struct target_backend_ops pscsi_ops = {

drivers/ufs/core/ufshpb.c

@@ -613,14 +613,17 @@ static void ufshpb_activate_subregion(struct ufshpb_lu *hpb,
 	srgn->srgn_state = HPB_SRGN_VALID;
 }
 
-static void ufshpb_umap_req_compl_fn(struct request *req, blk_status_t error)
+static enum rq_end_io_ret ufshpb_umap_req_compl_fn(struct request *req,
+						   blk_status_t error)
 {
 	struct ufshpb_req *umap_req = (struct ufshpb_req *)req->end_io_data;
 
 	ufshpb_put_req(umap_req->hpb, umap_req);
+	return RQ_END_IO_NONE;
 }
 
-static void ufshpb_map_req_compl_fn(struct request *req, blk_status_t error)
+static enum rq_end_io_ret ufshpb_map_req_compl_fn(struct request *req,
+						  blk_status_t error)
 {
 	struct ufshpb_req *map_req = (struct ufshpb_req *) req->end_io_data;
 	struct ufshpb_lu *hpb = map_req->hpb;
@@ -636,6 +639,7 @@ static void ufshpb_map_req_compl_fn(struct request *req, blk_status_t error)
 	spin_unlock_irqrestore(&hpb->rgn_state_lock, flags);
 
 	ufshpb_put_map_req(map_req->hpb, map_req);
+	return RQ_END_IO_NONE;
 }
 
 static void ufshpb_set_unmap_cmd(unsigned char *cdb, struct ufshpb_region *rgn)

include/linux/blk-mq.h

@@ -14,7 +14,12 @@ struct blk_flush_queue;
 #define BLKDEV_MIN_RQ	4
 #define BLKDEV_DEFAULT_RQ	128
 
-typedef void (rq_end_io_fn)(struct request *, blk_status_t);
+enum rq_end_io_ret {
+	RQ_END_IO_NONE,
+	RQ_END_IO_FREE,
+};
+
+typedef enum rq_end_io_ret (rq_end_io_fn)(struct request *, blk_status_t);
 
 /*
  * request flags */