Dma buf support optin (#905)

* dmaBufSupport Optin added on every part of the code that should invoke it

src/init.cc

@@ -444,11 +444,10 @@ NCCL_PARAM(GdrCopyFifoEnable, "GDRCOPY_FIFO_ENABLE", 1);
 NCCL_PARAM(WorkFifoDepth, "WORK_FIFO_DEPTH", 64<<10);
 enum ncclLaunchMode ncclParamLaunchMode;
 
-NCCL_PARAM(DmaBufEnable, "DMABUF_ENABLE", 0);
 
 // Detect DMA-BUF support
 static ncclResult_t dmaBufSupported(struct ncclComm* comm) {
-  if (ncclParamDmaBufEnable() == 0 || comm->ncclNet->regMrDmaBuf == NULL || rocmLibraryInit() != ncclSuccess) return ncclInternalError;
+  if (comm->ncclNet->regMrDmaBuf == NULL || rocmLibraryInit() != ncclSuccess) return ncclInternalError;
 #if CUDA_VERSION >= 11070
   int flag = 0;
   CUdevice dev;
@@ -1988,7 +1987,7 @@ constexpr nvtxPayloadSchemaEntry_t CommInitRankSchema[] = {
 NCCL_API(ncclResult_t, ncclCommInitRank, ncclComm_t* newcomm, int nranks, ncclUniqueId commId, int myrank);
 ncclResult_t ncclCommInitRank(ncclComm_t* newcomm, int nranks, ncclUniqueId commId, int myrank) {
   // Load the CUDA driver and dlsym hooks (can fail on old drivers)
-  if (ncclParamDmaBufEnable()) rocmLibraryInit();
+  rocmLibraryInit();
 
   int cudaDev;
   ncclConfig_t config = NCCL_CONFIG_INITIALIZER;
@@ -2014,7 +2013,7 @@ ncclResult_t ncclCommInitAll(ncclComm_t* comms, int ndev, const int* devlist) {
   NVTX3_FUNC_WITH_PARAMS(CommInitAll, CommInitAllSchema, ndev)
 
   // Load the CUDA driver and dlsym hooks (can fail on old drivers)
-  if (ncclParamDmaBufEnable()) (void) rocmLibraryInit();
+  rocmLibraryInit();
 
   NCCLCHECKGOTO(PtrCheck(comms, "CommInitAll", "comms"), ret, fail);
   if (ndev < 0) {
@@ -2078,7 +2077,7 @@ ncclResult_t ncclCommInitRankConfig(ncclComm_t *newcomm, int nranks, ncclUniqueI
   ncclConfig_t *internalConfigPtr = NULL;
   NCCLCHECK(ncclGroupStartInternal());
 
-  if (ncclParamDmaBufEnable()) (void) rocmLibraryInit();
+  rocmLibraryInit();
   CUDACHECKGOTO(cudaGetDevice(&cudaDev), ret, fail);
 
   if (config == NULL)

src/misc/rocmwrap.cc

@@ -9,6 +9,7 @@
 #include "debug.h"
 #include "rocmwrap.h"
 #include "hsa/hsa.h"
+#include "param.h"
 
 #include <dlfcn.h>
 #include <sys/utsname.h>
@@ -17,7 +18,7 @@
 #define DECLARE_ROCM_PFN(symbol) PFN_##symbol pfn_##symbol = nullptr
 
 DECLARE_ROCM_PFN(hsa_amd_portable_export_dmabuf); // DMA-BUF support
-
+NCCL_PARAM(DmaBufEnable, "DMABUF_ENABLE", 0);
 /* ROCr Driver functions loaded with dlsym() */
 DECLARE_ROCM_PFN(hsa_init);
 DECLARE_ROCM_PFN(hsa_system_get_info);
@@ -28,7 +29,6 @@ static enum { hsaUninitialized, hsaInitializing, hsaInitialized, hsaError } hsaS
 static void *hsaLib;
 static uint16_t version_major, version_minor;
 bool ncclCudaLaunchBlocking = false;
-bool dmaBufSupport = false;
 
 ncclResult_t rocmLibraryInit(void) {
   do {
@@ -36,6 +36,7 @@ ncclResult_t rocmLibraryInit(void) {
     ncclCudaLaunchBlocking = val!=nullptr && val[0]!=0 && !(val[0]=='0' && val[1]==0);
   } while (0);
 
+  bool dmaBufSupport = false;
   hsa_status_t res;
 
   if (hsaState == hsaInitialized)
@@ -108,14 +109,21 @@ ncclResult_t rocmLibraryInit(void) {
 
   /* DMA-BUF support */
   //ROCm support
+  if (ncclParamDmaBufEnable() == 0 ) {
+    INFO(NCCL_INIT, "Dmabuf feature disabled without NCCL_ENABLE_DMABUF_SUPPORT=1");
+    goto error;
+  }
   res = pfn_hsa_system_get_info((hsa_system_info_t) 0x204, &dmaBufSupport);
-  if (res != HSA_STATUS_SUCCESS || !dmaBufSupport) INFO(NCCL_INIT, "Current version of ROCm does not support dmabuf feature.");
+  if (res != HSA_STATUS_SUCCESS || !dmaBufSupport) {
+    INFO(NCCL_INIT, "Current version of ROCm does not support dmabuf feature.");
+    goto error;
+  }
   else {
     pfn_hsa_amd_portable_export_dmabuf = (PFN_hsa_amd_portable_export_dmabuf) dlsym(hsaLib, "hsa_amd_portable_export_dmabuf");
     if (pfn_hsa_amd_portable_export_dmabuf == NULL) {
       WARN("Failed to load ROCr missing symbol hsa_amd_portable_export_dmabuf");
       goto error;
-    } 
+    }
     else {
       //check OS kernel support
       struct utsname utsname;
@@ -126,7 +134,7 @@ ncclResult_t rocmLibraryInit(void) {
       char buf[256];
       int found_opt1 = 0;
       int found_opt2 = 0;
-      
+
       //check for kernel name exists
       if (uname(&utsname) == -1) INFO(NCCL_INIT,"Could not get kernel name");
       //format and store the kernel conf file location

src/transport/net_ib.cc

@@ -320,6 +320,7 @@ ncclResult_t ncclIbDmaBufSupport(int dev) {
   static int dmaBufSupported = -1;
   if (dmaBufSupported == -1) {
     ncclResult_t res;
+    NCCLCHECKGOTO(rocmLibraryInit(), res, failure);
     struct ibv_pd* pd;
     struct ibv_context* ctx;
     ctx = ncclIbDevs[dev].context;