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Revert "Fix a race condition between registering a callback and completing a request" #11499

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Merged
jsquyres merged 1 commit into from
Mar 21, 2023
Merged

Revert "Fix a race condition between registering a callback and completing a request" #11499

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32 changes: 12 additions & 20 deletions ompi/request/request.h
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Original file line number Diff line number Diff line change
Expand Up @@ -158,9 +158,6 @@ typedef struct ompi_request_t ompi_request_t;
#define REQUEST_PENDING (void *)0L
#define REQUEST_COMPLETED (void *)1L

#define REQUEST_CB_PENDING (void *)0L
#define REQUEST_CB_COMPLETED (void *)1L

struct ompi_predefined_request_t {
struct ompi_request_t request;
char padding[PREDEFINED_REQUEST_PAD - sizeof(ompi_request_t)];
Expand Down Expand Up @@ -520,12 +517,12 @@ static inline void ompi_request_wait_completion(ompi_request_t *req)
static inline int ompi_request_complete(ompi_request_t* request, bool with_signal)
{
int rc = 0;
ompi_request_complete_fn_t cb;
cb = (ompi_request_complete_fn_t)OPAL_ATOMIC_SWAP_PTR((opal_atomic_intptr_t*)&request->req_complete_cb,
(intptr_t)REQUEST_CB_COMPLETED);
if (REQUEST_CB_PENDING != cb) {
request->req_complete_cb = REQUEST_CB_PENDING;
rc = cb(request);

if(NULL != request->req_complete_cb) {
/* Set the request cb to NULL to allow resetting in the callback */
ompi_request_complete_fn_t fct = request->req_complete_cb;
request->req_complete_cb = NULL;
rc = fct( request );
}

if (0 == rc) {
Expand All @@ -549,17 +546,12 @@ static inline int ompi_request_set_callback(ompi_request_t* request,
void* cb_data)
{
request->req_complete_cb_data = cb_data;
opal_atomic_wmb();
if ((REQUEST_CB_COMPLETED == request->req_complete_cb) ||
(REQUEST_CB_COMPLETED == (void*)OPAL_ATOMIC_SWAP_PTR((opal_atomic_intptr_t*)&request->req_complete_cb,
(intptr_t)cb))) {
if (NULL != cb) {
/* the request was marked at least partially completed, make sure it's fully complete */
while (!REQUEST_COMPLETE(request)) {}
/* Set the request cb to NULL to allow resetting in the callback */
request->req_complete_cb = REQUEST_CB_PENDING;
cb(request);
}
request->req_complete_cb = cb;
/* If request is completed and the callback is not called, need to call callback */
if ((NULL != request->req_complete_cb) && (request->req_complete == REQUEST_COMPLETED)) {
ompi_request_complete_fn_t fct = request->req_complete_cb;
request->req_complete_cb = NULL;
return fct( request );
}
return OMPI_SUCCESS;
}
Expand Down