Minor tweaks to new H5P MPI code based on code review feedback.

2 files changed, 17 insertions, 23 deletions

diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index 13efcff..71e9fe1 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -792,20 +792,11 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id,
     if(NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a file access property list")
 
-    /* Set MPI communicator and info object */
-    if(H5P_FILE_ACCESS_DEFAULT == fapl_id || H5FD_MPIO != H5P_peek_driver(plist)) {
-        /* Non-parallel defaults */
-        if(FAIL == H5_mpi_comm_dup(MPI_COMM_SELF, &comm))
-            HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "communicator duplicate failed")
-        info = MPI_INFO_NULL;
-    }
-    else {
-        /* Get the MPI communicator and info object from the property list */
-        if(H5P_get(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, &comm) < 0)
-            HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI communicator")
-        if(H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
-            HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI info object")
-    }
+    /* Get the MPI communicator and info object from the property list */
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_COMM_NAME, &comm) < 0)
+        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI communicator")
+    if(H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI info object")
 
     /* Convert HDF5 flags to MPI-IO flags */
     /* Some combinations are illegal; let MPI-IO figure it out */
diff --git a/src/H5mpi.c b/src/H5mpi.c
index aec1e03..d48790b 100644
--- a/src/H5mpi.c
+++ b/src/H5mpi.c
@@ -239,6 +239,9 @@ H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result)
 
     /* Can't pass MPI_COMM_NULL to MPI_Comm_compare() so we have to handle
      * it in special cases.
+     *
+     * MPI_Comm can either be an integer type or a pointer. We cast them
+     * to intptr_t so we can compare them with < and > when needed.
      */
     if (MPI_COMM_NULL == comm1 && MPI_COMM_NULL == comm2) {
         /* Special case of both communicators being MPI_COMM_NULL */
@@ -247,7 +250,7 @@ H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result)
     else if (MPI_COMM_NULL == comm1 || MPI_COMM_NULL == comm2) {
 
         /* Special case of one communicator being MPI_COMM_NULL */
-        *result = (MPI_Datatype)comm1 < (MPI_Datatype)comm2 ? -1 : 1;
+        *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
     }
     else {
 
@@ -257,15 +260,11 @@ H5_mpi_comm_cmp(MPI_Comm comm1, MPI_Comm comm2, int *result)
         if (MPI_SUCCESS != (mpi_code = MPI_Comm_compare(comm1, comm2, &mpi_result)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Comm_compare failed", mpi_code)
 
-        /* Set the result
-         *
-         * The else clause should work regardless of whether MPI_Datatype is
-         * fundamentally an integer or a pointer.
-         */
+        /* Set the result */
         if (MPI_IDENT == mpi_result || MPI_CONGRUENT == mpi_result)
             *result = 0;
         else
-            *result = (MPI_Datatype)comm1 < (MPI_Datatype)comm2 ? -1 : 1;
+            *result = (intptr_t)comm1 < (intptr_t)comm2 ? -1 : 1;
     }
 
 done:
@@ -372,11 +371,15 @@ H5_mpi_info_cmp(MPI_Info info1, MPI_Info info2, int *result)
         } /* end else */
     } /* end else */
 
-    /* Set the output value */
+    /* Set the output value
+     *
+     * MPI_Info can either be an integer type or a pointer. We cast them
+     * to intptr_t so we can compare them with < and > when needed.
+     */
     if (same)
         *result = 0;
     else
-        *result = (MPI_Datatype)info1 < (MPI_Datatype)info2 ? -1 : 1;
+        *result = (intptr_t)info1 < (intptr_t)info2 ? -1 : 1;
 
 done:
     if (key)