[PATCH V2] libibverbs: Allow arbitrary int values for MTU.

[Jeff Squyres <jsquyres-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>]

Keep IBV_MTU_* enums values as they are, but pass MTU values around as
int's.  This is an ABI-compatible change; legacy applications will use
the enum values, but newer applications can use an int for values that
do not currently exist in the enum set (e.g., 1500, 9000).

(if people like the idea of this patch, I will send the corresponding
kernel patch)

Signed-off-by: Jeff Squyres <jsquyres-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
---
 Makefile.am                |  3 ++-
 examples/devinfo.c         | 20 +++-----------
 examples/pingpong.c        | 12 ---------
 examples/pingpong.h        |  1 -
 examples/rc_pingpong.c     |  8 +++---
 examples/srq_pingpong.c    |  8 +++---
 examples/uc_pingpong.c     |  8 +++---
 examples/ud_pingpong.c     |  2 +-
 include/infiniband/verbs.h | 55 ++++++++++++++++++++++++++++++++++---
 man/ibv_modify_qp.3        |  2 +-
 man/ibv_mtu_to_num.3       | 67 ++++++++++++++++++++++++++++++++++++++++++++++
 man/ibv_query_port.3       |  4 +--
 man/ibv_query_qp.3         |  2 +-
 13 files changed, 142 insertions(+), 50 deletions(-)
 create mode 100644 man/ibv_mtu_to_num.3

diff --git a/Makefile.am b/Makefile.am
index 40e83be..1159e55 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -54,7 +54,8 @@ man_MANS = man/ibv_asyncwatch.1 man/ibv_devices.1 man/ibv_devinfo.1	\
     man/ibv_post_srq_recv.3 man/ibv_query_device.3 man/ibv_query_gid.3	\
     man/ibv_query_pkey.3 man/ibv_query_port.3 man/ibv_query_qp.3	\
     man/ibv_query_srq.3 man/ibv_rate_to_mult.3 man/ibv_reg_mr.3		\
-    man/ibv_req_notify_cq.3 man/ibv_resize_cq.3 man/ibv_rate_to_mbps.3
+    man/ibv_req_notify_cq.3 man/ibv_resize_cq.3 man/ibv_rate_to_mbps.3  \
+    man/ibv_mtu_to_num.3
 
 DEBIAN = debian/changelog debian/compat debian/control debian/copyright \
     debian/ibverbs-utils.install debian/libibverbs1.install \
diff --git a/examples/devinfo.c b/examples/devinfo.c
index ff078e4..9f51dcb 100644
--- a/examples/devinfo.c
+++ b/examples/devinfo.c
@@ -111,18 +111,6 @@ static const char *atomic_cap_str(enum ibv_atomic_cap atom_cap)
 	}
 }
 
-static const char *mtu_str(enum ibv_mtu max_mtu)
-{
-	switch (max_mtu) {
-	case IBV_MTU_256:  return "256";
-	case IBV_MTU_512:  return "512";
-	case IBV_MTU_1024: return "1024";
-	case IBV_MTU_2048: return "2048";
-	case IBV_MTU_4096: return "4096";
-	default:           return "invalid MTU";
-	}
-}
-
 static const char *width_str(uint8_t width)
 {
 	switch (width) {
@@ -301,10 +289,10 @@ static int print_hca_cap(struct ibv_device *ib_dev, uint8_t ib_port)
 		printf("\t\tport:\t%d\n", port);
 		printf("\t\t\tstate:\t\t\t%s (%d)\n",
 		       port_state_str(port_attr.state), port_attr.state);
-		printf("\t\t\tmax_mtu:\t\t%s (%d)\n",
-		       mtu_str(port_attr.max_mtu), port_attr.max_mtu);
-		printf("\t\t\tactive_mtu:\t\t%s (%d)\n",
-		       mtu_str(port_attr.active_mtu), port_attr.active_mtu);
+		printf("\t\t\tmax_mtu:\t\t%d (%d)\n",
+		       ibv_mtu_to_num(port_attr.max_mtu), port_attr.max_mtu);
+		printf("\t\t\tactive_mtu:\t\t%d (%d)\n",
+		       ibv_mtu_to_num(port_attr.active_mtu), port_attr.active_mtu);
 		printf("\t\t\tsm_lid:\t\t\t%d\n", port_attr.sm_lid);
 		printf("\t\t\tport_lid:\t\t%d\n", port_attr.lid);
 		printf("\t\t\tport_lmc:\t\t0x%02x\n", port_attr.lmc);
diff --git a/examples/pingpong.c b/examples/pingpong.c
index 90732ef..d1c22c9 100644
--- a/examples/pingpong.c
+++ b/examples/pingpong.c
@@ -36,18 +36,6 @@
 #include <stdio.h>
 #include <string.h>
 
-enum ibv_mtu pp_mtu_to_enum(int mtu)
-{
-	switch (mtu) {
-	case 256:  return IBV_MTU_256;
-	case 512:  return IBV_MTU_512;
-	case 1024: return IBV_MTU_1024;
-	case 2048: return IBV_MTU_2048;
-	case 4096: return IBV_MTU_4096;
-	default:   return -1;
-	}
-}
-
 uint16_t pp_get_local_lid(struct ibv_context *context, int port)
 {
 	struct ibv_port_attr attr;
diff --git a/examples/pingpong.h b/examples/pingpong.h
index 9cdc03e..91d217b 100644
--- a/examples/pingpong.h
+++ b/examples/pingpong.h
@@ -35,7 +35,6 @@
 
 #include <infiniband/verbs.h>
 
-enum ibv_mtu pp_mtu_to_enum(int mtu);
 uint16_t pp_get_local_lid(struct ibv_context *context, int port);
 int pp_get_port_info(struct ibv_context *context, int port,
 		     struct ibv_port_attr *attr);
diff --git a/examples/rc_pingpong.c b/examples/rc_pingpong.c
index 15494a1..2d6d30e 100644
--- a/examples/rc_pingpong.c
+++ b/examples/rc_pingpong.c
@@ -78,7 +78,7 @@ struct pingpong_dest {
 };
 
 static int pp_connect_ctx(struct pingpong_context *ctx, int port, int my_psn,
-			  enum ibv_mtu mtu, int sl,
+			  ibv_mtu_t mtu, int sl,
 			  struct pingpong_dest *dest, int sgid_idx)
 {
 	struct ibv_qp_attr attr = {
@@ -209,7 +209,7 @@ out:
 }
 
 static struct pingpong_dest *pp_server_exch_dest(struct pingpong_context *ctx,
-						 int ib_port, enum ibv_mtu mtu,
+						 int ib_port, ibv_mtu_t mtu,
 						 int port, int sl,
 						 const struct pingpong_dest *my_dest,
 						 int sgid_idx)
@@ -547,7 +547,7 @@ int main(int argc, char *argv[])
 	int                      port = 18515;
 	int                      ib_port = 1;
 	int                      size = 4096;
-	enum ibv_mtu		 mtu = IBV_MTU_1024;
+	ibv_mtu_t		 mtu = num_to_ibv_mtu(1024);
 	int                      rx_depth = 500;
 	int                      iters = 1000;
 	int                      use_event = 0;
@@ -608,7 +608,7 @@ int main(int argc, char *argv[])
 			break;
 
 		case 'm':
-			mtu = pp_mtu_to_enum(strtol(optarg, NULL, 0));
+			mtu = num_to_ibv_mtu(strtol(optarg, NULL, 0));
 			if (mtu < 0) {
 				usage(argv[0]);
 				return 1;
diff --git a/examples/srq_pingpong.c b/examples/srq_pingpong.c
index 6e00f8c..44915a7 100644
--- a/examples/srq_pingpong.c
+++ b/examples/srq_pingpong.c
@@ -81,7 +81,7 @@ struct pingpong_dest {
 	union ibv_gid gid;
 };
 
-static int pp_connect_ctx(struct pingpong_context *ctx, int port, enum ibv_mtu mtu,
+static int pp_connect_ctx(struct pingpong_context *ctx, int port, ibv_mtu_t mtu,
 			  int sl, const struct pingpong_dest *my_dest,
 			  const struct pingpong_dest *dest, int sgid_idx)
 {
@@ -229,7 +229,7 @@ out:
 }
 
 static struct pingpong_dest *pp_server_exch_dest(struct pingpong_context *ctx,
-						 int ib_port, enum ibv_mtu mtu,
+						 int ib_port, ibv_mtu_t mtu,
 						 int port, int sl,
 						 const struct pingpong_dest *my_dest,
 						 int sgid_idx)
@@ -620,7 +620,7 @@ int main(int argc, char *argv[])
 	int                      port = 18515;
 	int                      ib_port = 1;
 	int                      size = 4096;
-	enum ibv_mtu		 mtu = IBV_MTU_1024;
+	ibv_mtu_t		 mtu = num_to_ibv_mtu(1024);
 	int                      num_qp = 16;
 	int                      rx_depth = 500;
 	int                      iters = 1000;
@@ -685,7 +685,7 @@ int main(int argc, char *argv[])
 			break;
 
 		case 'm':
-			mtu = pp_mtu_to_enum(strtol(optarg, NULL, 0));
+			mtu = num_to_ibv_mtu(strtol(optarg, NULL, 0));
 			if (mtu < 0) {
 				usage(argv[0]);
 				return 1;
diff --git a/examples/uc_pingpong.c b/examples/uc_pingpong.c
index 52c6c28..bafc2a6 100644
--- a/examples/uc_pingpong.c
+++ b/examples/uc_pingpong.c
@@ -78,7 +78,7 @@ struct pingpong_dest {
 };
 
 static int pp_connect_ctx(struct pingpong_context *ctx, int port, int my_psn,
-			  enum ibv_mtu mtu, int sl,
+			  ibv_mtu_t mtu, int sl,
 			  struct pingpong_dest *dest, int sgid_idx)
 {
 	struct ibv_qp_attr attr = {
@@ -197,7 +197,7 @@ out:
 }
 
 static struct pingpong_dest *pp_server_exch_dest(struct pingpong_context *ctx,
-						 int ib_port, enum ibv_mtu mtu,
+						 int ib_port, ibv_mtu_t mtu,
 						 int port, int sl,
 						 const struct pingpong_dest *my_dest,
 						 int sgid_idx)
@@ -535,7 +535,7 @@ int main(int argc, char *argv[])
 	int                      port = 18515;
 	int                      ib_port = 1;
 	int                      size = 4096;
-	enum ibv_mtu		 mtu = IBV_MTU_1024;
+	ibv_mtu_t		 mtu = num_to_ibv_mtu(1024);
 	int                      rx_depth = 500;
 	int                      iters = 1000;
 	int                      use_event = 0;
@@ -596,7 +596,7 @@ int main(int argc, char *argv[])
 			break;
 
 		case 'm':
-			mtu = pp_mtu_to_enum(strtol(optarg, NULL, 0));
+			mtu = num_to_ibv_mtu(strtol(optarg, NULL, 0));
 			if (mtu < 0) {
 				usage(argv[0]);
 				return 1;
diff --git a/examples/ud_pingpong.c b/examples/ud_pingpong.c
index 21c551d..5a0656f 100644
--- a/examples/ud_pingpong.c
+++ b/examples/ud_pingpong.c
@@ -332,7 +332,7 @@ static struct pingpong_context *pp_init_ctx(struct ibv_device *ib_dev, int size,
 			fprintf(stderr, "Unable to query port info for port %d\n", port);
 			goto clean_device;
 		}
-		mtu = 1 << (port_info.active_mtu + 7);
+		mtu = ibv_mtu_to_num(port_info.active_mtu);
 		if (size > mtu) {
 			fprintf(stderr, "Requested size larger than port MTU (%d)\n", mtu);
 			goto clean_device;
diff --git a/include/infiniband/verbs.h b/include/infiniband/verbs.h
index 4b1ab57..2108629 100644
--- a/include/infiniband/verbs.h
+++ b/include/infiniband/verbs.h
@@ -144,6 +144,10 @@ struct ibv_device_attr {
 	uint8_t			phys_port_cnt;
 };
 
+/*
+ * Symbolic enum names for MTU values are preserved for backwards
+ * compatibility.
+ */
 enum ibv_mtu {
 	IBV_MTU_256  = 1,
 	IBV_MTU_512  = 2,
@@ -152,6 +156,14 @@ enum ibv_mtu {
 	IBV_MTU_4096 = 5
 };
 
+/*
+ * ibv_mtu_t is an encoded integer type that represents an MTU value.
+ * If the value is <= IBV_MTU_4096, it is treated as one of the
+ * IBV_MTU_* enum values.  Otherwise, it is treated as its integer
+ * value.
+ */
+typedef int ibv_mtu_t;
+
 enum ibv_port_state {
 	IBV_PORT_NOP		= 0,
 	IBV_PORT_DOWN		= 1,
@@ -169,8 +181,8 @@ enum {
 
 struct ibv_port_attr {
 	enum ibv_port_state	state;
-	enum ibv_mtu		max_mtu;
-	enum ibv_mtu		active_mtu;
+	ibv_mtu_t		max_mtu;
+	ibv_mtu_t		active_mtu;
 	int			gid_tbl_len;
 	uint32_t		port_cap_flags;
 	uint32_t		max_msg_sz;
@@ -485,7 +497,7 @@ enum ibv_mig_state {
 struct ibv_qp_attr {
 	enum ibv_qp_state	qp_state;
 	enum ibv_qp_state	cur_qp_state;
-	enum ibv_mtu		path_mtu;
+	ibv_mtu_t		path_mtu;
 	enum ibv_mig_state	path_mig_state;
 	uint32_t		qkey;
 	uint32_t		rq_psn;
@@ -1138,6 +1150,43 @@ const char *ibv_port_state_str(enum ibv_port_state port_state);
  */
 const char *ibv_event_type_str(enum ibv_event_type event);
 
+/**
+ * num_to_ibv_mtu - Convert an integer to its corresponding encoded
+ * ibv_mtu_t value.  If an integer value corresponding to an IBV_MTU_*
+ * enum value is passed, return the enum value (e.g., 1024 ->
+ * IBV_MTU_1024).  Otherwise, just return the value (e.g., 1500 ->
+ * 1500).
+ */
+static inline ibv_mtu_t num_to_ibv_mtu(int num)
+{
+	switch (num) {
+	case 256:  return IBV_MTU_256;
+	case 512:  return IBV_MTU_512;
+	case 1024: return IBV_MTU_1024;
+	case 2048: return IBV_MTU_2048;
+	case 4096: return IBV_MTU_4096;
+	default:   return num;
+	}
+}
+
+/**
+ * ibv_mtu_to_num - Convert an encoded ibv_mtu_t value to its
+ * corresponding integer value.  If an enum ibv_mtu value is passed,
+ * return its integer value (e.g., IBV_MTU_1024 -> 1024).  Otherwise,
+ * just return the value (e.g., 1500 -> 1500).
+ */
+static inline int ibv_mtu_to_num(ibv_mtu_t mtu)
+{
+	switch (mtu) {
+	case IBV_MTU_256:  return 256;
+	case IBV_MTU_512:  return 512;
+	case IBV_MTU_1024: return 1024;
+	case IBV_MTU_2048: return 2048;
+	case IBV_MTU_4096: return 4096;
+	default:           return mtu;
+	}
+}
+
 END_C_DECLS
 
 #  undef __attribute_const
diff --git a/man/ibv_modify_qp.3 b/man/ibv_modify_qp.3
index cb3faaa..26dfcf3 100644
--- a/man/ibv_modify_qp.3
+++ b/man/ibv_modify_qp.3
@@ -25,7 +25,7 @@ struct ibv_qp_attr {
 .in +8
 enum ibv_qp_state       qp_state;               /* Move the QP to this state */
 enum ibv_qp_state       cur_qp_state;           /* Assume this is the current QP state */
-enum ibv_mtu            path_mtu;               /* Path MTU (valid only for RC/UC QPs) */
+ibv_mtu_t               path_mtu;               /* Path MTU (valid only for RC/UC QPs) */
 enum ibv_mig_state      path_mig_state;         /* Path migration state (valid if HCA supports APM) */
 uint32_t                qkey;                   /* Q_Key for the QP (valid only for UD QPs) */
 uint32_t                rq_psn;                 /* PSN for receive queue (valid only for RC/UC QPs) */
diff --git a/man/ibv_mtu_to_num.3 b/man/ibv_mtu_to_num.3
new file mode 100644
index 0000000..5603efa
--- /dev/null
+++ b/man/ibv_mtu_to_num.3
@@ -0,0 +1,67 @@
+.\" -*- nroff -*-
+.\"
+.TH IBV_MTU_TO_NUM 3 2013-06-20 libibverbs "Libibverbs Programmer's Manual"
+.SH "NAME"
+.nf
+ibv_mtu_to_num \- convert encoded MTU value to integer
+.sp
+num_to_ibv_mtu \- convert integer to encoded MTU value
+.SH "SYNOPSIS"
+.nf
+.B #include <infiniband/verbs.h>
+.sp
+.BI "int ibv_mtu_to_num(ibv_mtu_t " "mtu" ");
+.sp
+.BI "ibv_mtu_t num_to_ibv_mtu(int " "num" ");
+.fi
+.SH "DESCRIPTION"
+.PP
+The
+.I ibv_mtu_t
+type is an encoded integer used to represent MTU values in order to
+preserve backwards compatibility.  When the value of an
+.I ibv_mtu_t
+variable is <=
+.BR IBV_MTU_4096\fR,
+it is treated as the corresponding
+.B IBV_MTU_*
+enum value.  Otherwise, it is treated as its integer value.
+.PP
+MTU values less than the value of the enum
+.B IBV_MTU_4096
+(i.e., 5) cannot be represented.
+.PP
+.B ibv_mtu_to_num()
+converts the encoded MTU value
+.I mtu
+to a plain integer value.  For example, if
+.I mtu
+is
+.BR IBV_MTU_1024\fR,
+the value 1024 will be returned.  Likewise, if
+.I mtu
+is 1500, then 1500 will be returned.
+.PP
+.B num_to_ibv_mtu()
+converts the integer
+.I num
+to its corresponding encoded
+.I ibv_mtu_t
+value.  For example, if
+.I num
+is 1024, then
+.B IBV_MTU_1024
+will be returned.  Likewise, if
+.I num
+is 1500, then 1500 will be returned.
+.SH "RETURN VALUE"
+.B ibv_mtu_to_num()
+returns an integer MTU value.
+.PP
+.B num_to_ibv_mtu()
+returns an encoded MTU value.
+.SH "SEE ALSO"
+.BR ibv_query_port (3)
+.SH "AUTHORS"
+.TP
+Jeff Squyres <jsquyres-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>
diff --git a/man/ibv_query_port.3 b/man/ibv_query_port.3
index 9bedd90..3700a5e 100644
--- a/man/ibv_query_port.3
+++ b/man/ibv_query_port.3
@@ -26,8 +26,8 @@ is an ibv_port_attr struct, as defined in <infiniband/verbs.h>.
 struct ibv_port_attr {
 .in +8
 enum ibv_port_state     state;          /* Logical port state */
-enum ibv_mtu            max_mtu;        /* Max MTU supported by port */
-enum ibv_mtu            active_mtu;     /* Actual MTU */
+ibv_mtu_t               max_mtu;        /* Max MTU supported by port */
+ibv_mtu_t               active_mtu;     /* Actual MTU */
 int                     gid_tbl_len;    /* Length of source GID table */
 uint32_t                port_cap_flags; /* Port capabilities */
 uint32_t                max_msg_sz;     /* Maximum message size */
diff --git a/man/ibv_query_qp.3 b/man/ibv_query_qp.3
index 3893ec8..ad7d9d5 100644
--- a/man/ibv_query_qp.3
+++ b/man/ibv_query_qp.3
@@ -30,7 +30,7 @@ struct ibv_qp_attr {
 .in +8
 enum ibv_qp_state       qp_state;            /* Current QP state */
 enum ibv_qp_state       cur_qp_state;        /* Current QP state - irrelevant for ibv_query_qp */
-enum ibv_mtu            path_mtu;            /* Path MTU (valid only for RC/UC QPs) */
+ibv_mtu_t               path_mtu;            /* Path MTU (valid only for RC/UC QPs) */
 enum ibv_mig_state      path_mig_state;      /* Path migration state (valid if HCA supports APM) */
 uint32_t                qkey;                /* Q_Key of the QP (valid only for UD QPs) */
 uint32_t                rq_psn;              /* PSN for receive queue (valid only for RC/UC QPs) */
-- 
1.8.2.1

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