nvme: split out a nvme_identify_ns_nvm helper

Split the logic to query the Identify Namespace Data Structure, NVM
Command Set into a separate helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: Christoph Hellwig

drivers/nvme/host/core.c

@@ -1831,12 +1831,35 @@ static bool nvme_ns_ids_equal(struct nvme_ns_ids *a, struct nvme_ns_ids *b)
 		a->csi == b->csi;
 }
 
+static int nvme_identify_ns_nvm(struct nvme_ctrl *ctrl, unsigned int nsid,
+		struct nvme_id_ns_nvm **nvmp)
+{
+	struct nvme_command c = {
+		.identify.opcode	= nvme_admin_identify,
+		.identify.nsid		= cpu_to_le32(nsid),
+		.identify.cns		= NVME_ID_CNS_CS_NS,
+		.identify.csi		= NVME_CSI_NVM,
+	};
+	struct nvme_id_ns_nvm *nvm;
+	int ret;
+
+	nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
+	if (!nvm)
+		return -ENOMEM;
+
+	ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, nvm, sizeof(*nvm));
+	if (ret)
+		kfree(nvm);
+	else
+		*nvmp = nvm;
+	return ret;
+}
+
 static int nvme_init_ms(struct nvme_ctrl *ctrl, struct nvme_ns_head *head,
 		struct nvme_id_ns *id)
 {
 	bool first = id->dps & NVME_NS_DPS_PI_FIRST;
 	unsigned lbaf = nvme_lbaf_index(id->flbas);
-	struct nvme_command c = { };
 	struct nvme_id_ns_nvm *nvm;
 	int ret = 0;
 	u32 elbaf;
@@ -1849,18 +1872,9 @@ static int nvme_init_ms(struct nvme_ctrl *ctrl, struct nvme_ns_head *head,
 		goto set_pi;
 	}
 
-	nvm = kzalloc(sizeof(*nvm), GFP_KERNEL);
-	if (!nvm)
-		return -ENOMEM;
-
-	c.identify.opcode = nvme_admin_identify;
-	c.identify.nsid = cpu_to_le32(head->ns_id);
-	c.identify.cns = NVME_ID_CNS_CS_NS;
-	c.identify.csi = NVME_CSI_NVM;
-
-	ret = nvme_submit_sync_cmd(ctrl->admin_q, &c, nvm, sizeof(*nvm));
+	ret = nvme_identify_ns_nvm(ctrl, head->ns_id, &nvm);
 	if (ret)
-		goto free_data;
+		goto set_pi;
 
 	elbaf = le32_to_cpu(nvm->elbaf[lbaf]);