nvme: fix potential memory leak in option parsing

When specifying same string type option several times,
current option parsing may cause memory leak. Hence,
call kfree for previous one in this case.
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/host/fabrics.c

@@ -668,6 +668,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -ENOMEM;
 				goto out;
 			}
+			kfree(opts->transport);
 			opts->transport = p;
 			break;
 		case NVMF_OPT_NQN:
@@ -676,6 +677,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -ENOMEM;
 				goto out;
 			}
+			kfree(opts->subsysnqn);
 			opts->subsysnqn = p;
 			nqnlen = strlen(opts->subsysnqn);
 			if (nqnlen >= NVMF_NQN_SIZE) {
@@ -698,6 +700,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -ENOMEM;
 				goto out;
 			}
+			kfree(opts->traddr);
 			opts->traddr = p;
 			break;
 		case NVMF_OPT_TRSVCID:
@@ -706,6 +709,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -ENOMEM;
 				goto out;
 			}
+			kfree(opts->trsvcid);
 			opts->trsvcid = p;
 			break;
 		case NVMF_OPT_QUEUE_SIZE:
@@ -792,6 +796,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -EINVAL;
 				goto out;
 			}
+			nvmf_host_put(opts->host);
 			opts->host = nvmf_host_add(p);
 			kfree(p);
 			if (!opts->host) {
@@ -817,6 +822,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 				ret = -ENOMEM;
 				goto out;
 			}
+			kfree(opts->host_traddr);
 			opts->host_traddr = p;
 			break;
 		case NVMF_OPT_HOST_ID: