nvmet-fc: move lsop put work to nvmet_fc_ls_req_op

It’s possible for more than one async command to be in flight from
__nvmet_fc_send_ls_req. For each command, a tgtport reference is taken.

In the current code, only one put work item is queued at a time, which
results in a leaked reference.

To fix this, move the work item to the nvmet_fc_ls_req_op struct, which
already tracks all resources related to the command.

Fixes: 710c69d ("nvmet-fc: avoid deadlock on delete association path")
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: igaw

drivers/nvme/target/fc.c

@@ -54,6 +54,8 @@ struct nvmet_fc_ls_req_op {		/* for an LS RQST XMT */
 	int				ls_error;
 	struct list_head		lsreq_list; /* tgtport->ls_req_list */
 	bool				req_queued;
+
+	struct work_struct		put_work;
 };
 
 
@@ -111,8 +113,6 @@ struct nvmet_fc_tgtport {
 	struct nvmet_fc_port_entry	*pe;
 	struct kref			ref;
 	u32				max_sg_cnt;
-
-	struct work_struct		put_work;
 };
 
 struct nvmet_fc_port_entry {
@@ -235,12 +235,13 @@ static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
 static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
 static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
 static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
-static void nvmet_fc_put_tgtport_work(struct work_struct *work)
+static void nvmet_fc_put_lsop_work(struct work_struct *work)
 {
-	struct nvmet_fc_tgtport *tgtport =
-		container_of(work, struct nvmet_fc_tgtport, put_work);
+	struct nvmet_fc_ls_req_op *lsop =
+		container_of(work, struct nvmet_fc_ls_req_op, put_work);
 
-	nvmet_fc_tgtport_put(tgtport);
+	nvmet_fc_tgtport_put(lsop->tgtport);
+	kfree(lsop);
 }
 static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);
 static void nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
@@ -367,7 +368,7 @@ __nvmet_fc_finish_ls_req(struct nvmet_fc_ls_req_op *lsop)
 				  DMA_BIDIRECTIONAL);
 
 out_putwork:
-	queue_work(nvmet_wq, &tgtport->put_work);
+	queue_work(nvmet_wq, &lsop->put_work);
 }
 
 static int
@@ -388,6 +389,7 @@ __nvmet_fc_send_ls_req(struct nvmet_fc_tgtport *tgtport,
 	lsreq->done = done;
 	lsop->req_queued = false;
 	INIT_LIST_HEAD(&lsop->lsreq_list);
+	INIT_WORK(&lsop->put_work, nvmet_fc_put_lsop_work);
 
 	lsreq->rqstdma = fc_dma_map_single(tgtport->dev, lsreq->rqstaddr,
 				  lsreq->rqstlen + lsreq->rsplen,
@@ -447,8 +449,6 @@ nvmet_fc_disconnect_assoc_done(struct nvmefc_ls_req *lsreq, int status)
 	__nvmet_fc_finish_ls_req(lsop);
 
 	/* fc-nvme target doesn't care about success or failure of cmd */
-
-	kfree(lsop);
 }
 
 /*
@@ -1410,7 +1410,6 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
 	kref_init(&newrec->ref);
 	ida_init(&newrec->assoc_cnt);
 	newrec->max_sg_cnt = template->max_sgl_segments;
-	INIT_WORK(&newrec->put_work, nvmet_fc_put_tgtport_work);
 
 	ret = nvmet_fc_alloc_ls_iodlist(newrec);
 	if (ret) {