nvme-fabrics: Add type of service (TOS) configuration

TOS is user-defined and needs to be configured via nvme-cli.
It must be set before initiating any traffic and once set the TOS
cannot be changed.
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

drivers/nvme/host/fabrics.c

@@ -611,6 +611,7 @@ static const match_table_t opt_tokens = {
 	{ NVMF_OPT_DATA_DIGEST,		"data_digest"		},
 	{ NVMF_OPT_NR_WRITE_QUEUES,	"nr_write_queues=%d"	},
 	{ NVMF_OPT_NR_POLL_QUEUES,	"nr_poll_queues=%d"	},
+	{ NVMF_OPT_TOS,			"tos=%d"		},
 	{ NVMF_OPT_ERR,			NULL			}
 };
 
@@ -632,6 +633,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	opts->duplicate_connect = false;
 	opts->hdr_digest = false;
 	opts->data_digest = false;
+	opts->tos = -1; /* < 0 == use transport default */
 
 	options = o = kstrdup(buf, GFP_KERNEL);
 	if (!options)
@@ -856,6 +858,22 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			opts->nr_poll_queues = token;
 			break;
+		case NVMF_OPT_TOS:
+			if (match_int(args, &token)) {
+				ret = -EINVAL;
+				goto out;
+			}
+			if (token < 0) {
+				pr_err("Invalid type of service %d\n", token);
+				ret = -EINVAL;
+				goto out;
+			}
+			if (token > 255) {
+				pr_warn("Clamping type of service to 255\n");
+				token = 255;
+			}
+			opts->tos = token;
+			break;
 		default:
 			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
 				p);

drivers/nvme/host/fabrics.h

@@ -55,6 +55,7 @@ enum {
 	NVMF_OPT_DATA_DIGEST	= 1 << 16,
 	NVMF_OPT_NR_WRITE_QUEUES = 1 << 17,
 	NVMF_OPT_NR_POLL_QUEUES = 1 << 18,
+	NVMF_OPT_TOS		= 1 << 19,
 };
 
 /**
@@ -87,6 +88,7 @@ enum {
  * @data_digest: generate/verify data digest (TCP)
  * @nr_write_queues: number of queues for write I/O
  * @nr_poll_queues: number of queues for polling I/O
+ * @tos: type of service
  */
 struct nvmf_ctrl_options {
 	unsigned		mask;
@@ -108,6 +110,7 @@ struct nvmf_ctrl_options {
 	bool			data_digest;
 	unsigned int		nr_write_queues;
 	unsigned int		nr_poll_queues;
+	int			tos;
 };
 
 /*