From e7a9041e93f64fcf9220e89d0db8e353871f48f6 Mon Sep 17 00:00:00 2001
From: Hui Zhou <hzhou321@anl.gov>
Date: Thu, 14 Apr 2022 11:30:31 -0500
Subject: [PATCH] ADI: add MPID_Allocate_vci

This ADI allows MPIR layer to request for explicit vcis. The return must
be greater than 0 or inidicate failure. VCI 0 is the default global vci,
that is always used for implicit vci hashing..
---
 src/mpid/ch3/include/mpidpre.h |  2 ++
 src/mpid/ch3/src/mpid_init.c   |  6 ++++++
 src/mpid/ch4/include/mpidch4.h |  1 +
 src/mpid/ch4/src/ch4_init.c    | 11 +++++++++++
 4 files changed, 20 insertions(+)

diff --git a/src/mpid/ch3/include/mpidpre.h b/src/mpid/ch3/include/mpidpre.h
index c2e21435593..af4ba57d0c6 100644
--- a/src/mpid/ch3/include/mpidpre.h
+++ b/src/mpid/ch3/include/mpidpre.h
@@ -532,6 +532,8 @@ int MPID_Init(int required, int *provided);
 
 int MPID_InitCompleted( void );
 
+int MPID_Allocate_vci(void);
+
 int MPID_Finalize(void);
 
 int MPID_Abort( MPIR_Comm *comm, int mpi_errno, int exit_code, const char *error_msg );
diff --git a/src/mpid/ch3/src/mpid_init.c b/src/mpid/ch3/src/mpid_init.c
index 3218c978ec7..1804f8392e0 100644
--- a/src/mpid/ch3/src/mpid_init.c
+++ b/src/mpid/ch3/src/mpid_init.c
@@ -265,6 +265,12 @@ int MPID_InitCompleted( void )
     /* --END ERROR HANDLING-- */
 }
 
+int MPID_Allocate_vci(void)
+{
+    /* not supported, return 0 as failure */
+    return 0;
+}
+
 /*
  * Initialize the process group structure by using PMI calls.
  * This routine initializes PMI and uses PMI calls to setup the 
diff --git a/src/mpid/ch4/include/mpidch4.h b/src/mpid/ch4/include/mpidch4.h
index 59983db2cf0..4ea9cee59b9 100644
--- a/src/mpid/ch4/include/mpidch4.h
+++ b/src/mpid/ch4/include/mpidch4.h
@@ -14,6 +14,7 @@
 
 int MPID_Init(int, int *);
 int MPID_InitCompleted(void);
+int MPID_Allocate_vci(void);
 MPL_STATIC_INLINE_PREFIX int MPID_Cancel_recv(MPIR_Request *) MPL_STATIC_INLINE_SUFFIX;
 MPL_STATIC_INLINE_PREFIX int MPID_Cancel_send(MPIR_Request *) MPL_STATIC_INLINE_SUFFIX;
 int MPID_Comm_disconnect(MPIR_Comm *);
diff --git a/src/mpid/ch4/src/ch4_init.c b/src/mpid/ch4/src/ch4_init.c
index db7327f2abe..96787d52268 100644
--- a/src/mpid/ch4/src/ch4_init.c
+++ b/src/mpid/ch4/src/ch4_init.c
@@ -518,6 +518,17 @@ int MPID_InitCompleted(void)
     goto fn_exit;
 }
 
+int MPID_Allocate_vci(void)
+{
+    if (MPIDI_global.n_vcis + MPIDI_global.n_reserved_vcis >= MPIDI_global.n_total_vcis) {
+        return 0;
+    } else {
+        MPIDI_global.n_reserved_vcis++;
+        /* we allocate from the back */
+        return (MPIDI_global.n_total_vcis - MPIDI_global.n_reserved_vcis);
+    }
+}
+
 int MPID_Finalize(void)
 {
     int mpi_errno;