nvme: Use CNS as 8-bit field and avoid endianness conversion

This patch defines CNS field as 8-bit field and avoids cpu_to/from_le
conversions.
Also initialize nvme_command cns value explicitly to NVME_ID_CNS_NS
for readability (don't rely on the fact that NVME_ID_CNS_NS = 0).

Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

4 files changed, 9 insertions, 6 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index a68bf6954ead..8b1be128b66e 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -560,7 +560,7 @@ int nvme_identify_ctrl(struct nvme_ctrl *dev, struct nvme_id_ctrl **id)
 
         /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
         c.identify.opcode = nvme_admin_identify;
-        c.identify.cns = cpu_to_le32(NVME_ID_CNS_CTRL);
+        c.identify.cns = NVME_ID_CNS_CTRL;
 
         *id = kmalloc(sizeof(struct nvme_id_ctrl), GFP_KERNEL);
         if (!*id)
@@ -578,7 +578,7 @@ static int nvme_identify_ns_list(struct nvme_ctrl *dev, unsigned nsid, __le32 *n
         struct nvme_command c = { };
 
         c.identify.opcode = nvme_admin_identify;
-        c.identify.cns = cpu_to_le32(NVME_ID_CNS_NS_ACTIVE_LIST);
+        c.identify.cns = NVME_ID_CNS_NS_ACTIVE_LIST;
         c.identify.nsid = cpu_to_le32(nsid);
         return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list, 0x1000);
 }
@@ -592,6 +592,7 @@ int nvme_identify_ns(struct nvme_ctrl *dev, unsigned nsid,
         /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
         c.identify.opcode = nvme_admin_identify;
         c.identify.nsid = cpu_to_le32(nsid);
+        c.identify.cns = NVME_ID_CNS_NS;
 
         *id = kmalloc(sizeof(struct nvme_id_ns), GFP_KERNEL);
         if (!*id)
diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 204e85efebab..94e524fea568 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -509,7 +509,7 @@ int nvmet_parse_admin_cmd(struct nvmet_req *req)
                 break;
         case nvme_admin_identify:
                 req->data_len = 4096;
-                switch (le32_to_cpu(cmd->identify.cns)) {
+                switch (cmd->identify.cns) {
                 case NVME_ID_CNS_NS:
                         req->execute = nvmet_execute_identify_ns;
                         return 0;
diff --git a/drivers/nvme/target/discovery.c b/drivers/nvme/target/discovery.c
index 12f39eea569f..af8aabf05335 100644
--- a/drivers/nvme/target/discovery.c
+++ b/drivers/nvme/target/discovery.c
@@ -186,14 +186,14 @@ int nvmet_parse_discovery_cmd(struct nvmet_req *req)
                 }
         case nvme_admin_identify:
                 req->data_len = 4096;
-                switch (le32_to_cpu(cmd->identify.cns)) {
+                switch (cmd->identify.cns) {
                 case NVME_ID_CNS_CTRL:
                         req->execute =
                                 nvmet_execute_identify_disc_ctrl;
                         return 0;
                 default:
                         pr_err("nvmet: unsupported identify cns %d\n",
-                                le32_to_cpu(cmd->identify.cns));
+                                cmd->identify.cns);
                         return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
                 }
         default:
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 0b676a02cf3e..5b32521456d6 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -644,7 +644,9 @@ struct nvme_identify {
         __le32                  nsid;
         __u64                   rsvd2[2];
         union nvme_data_ptr     dptr;
-        __le32                  cns;
+        __u8                    cns;
+        __u8                    rsvd3;
+        __le16                  ctrlid;
         __u32                   rsvd11[5];
 };