[openib-general] Re: can i post a send request with 0 bytes with the inline bit enabled?

[Roland Dreier]

    Dotan> should the driver handle it? (and post send of 0 bytes with
    Dotan> inline enabled should generate good completion) or the user
    Dotan> should know that this scenario is illegal?

I guess we might as well fix it.  I checked in the following patch.

 - R.


Index: libmthca/src/qp.c
===================================================================
--- libmthca/src/qp.c	(revision 4182)
+++ libmthca/src/qp.c	(working copy)
@@ -230,27 +230,30 @@ int mthca_tavor_post_send(struct ibv_qp 
 		}
 
 		if (wr->send_flags & IBV_SEND_INLINE) {
-			struct mthca_inline_seg *seg = wqe;
-			int s = 0;
+			if (wr->num_sge) {
+				struct mthca_inline_seg *seg = wqe;
+				int s = 0;
 
-			wqe += sizeof *seg;
-			for (i = 0; i < wr->num_sge; ++i) {
-				struct ibv_sge *sge = &wr->sg_list[i];
+				wqe += sizeof *seg;
+				for (i = 0; i < wr->num_sge; ++i) {
+					struct ibv_sge *sge = &wr->sg_list[i];
 
-				s += sge->length;
+					s += sge->length;
 
-				if (s > qp->max_inline_data) {
-					ret = -1;
-					*bad_wr = wr;
-					goto out;
+					if (s > qp->max_inline_data) {
+						ret = -1;
+						*bad_wr = wr;
+						goto out;
+					}
+
+					memcpy(wqe, (void *) (intptr_t) sge->addr,
+					       sge->length);
+					wqe += sge->length;
 				}
 
-				memcpy(wqe, (void*) (intptr_t) sge->addr, sge->length);
-				wqe += sge->length;
+				seg->byte_count = htonl(MTHCA_INLINE_SEG | s);
+				size += align(s + sizeof *seg, 16) / 16;
 			}
-
-			seg->byte_count = htonl(MTHCA_INLINE_SEG | s);
-			size += align(s + sizeof *seg, 16) / 16;
 		} else {
 			struct mthca_data_seg *seg;
 
@@ -551,27 +554,30 @@ int mthca_arbel_post_send(struct ibv_qp 
 		}
 
 		if (wr->send_flags & IBV_SEND_INLINE) {
-			struct mthca_inline_seg *seg = wqe;
-			int s = 0;
+			if (wr->num_sge) {
+				struct mthca_inline_seg *seg = wqe;
+				int s = 0;
 
-			wqe += sizeof *seg;
-			for (i = 0; i < wr->num_sge; ++i) {
-				struct ibv_sge *sge = &wr->sg_list[i];
+				wqe += sizeof *seg;
+				for (i = 0; i < wr->num_sge; ++i) {
+					struct ibv_sge *sge = &wr->sg_list[i];
 
-				s += sge->length;
+					s += sge->length;
 
-				if (s > qp->max_inline_data) {
-					ret = -1;
-					*bad_wr = wr;
-					goto out;
+					if (s > qp->max_inline_data) {
+						ret = -1;
+						*bad_wr = wr;
+						goto out;
+					}
+
+					memcpy(wqe, (void *) (uintptr_t) sge->addr,
+					       sge->length);
+					wqe += sge->length;
 				}
 
-				memcpy(wqe, (void*) (uintptr_t) sge->addr, sge->length);
-				wqe += sge->length;
+				seg->byte_count = htonl(MTHCA_INLINE_SEG | s);
+				size += align(s + sizeof *seg, 16) / 16;
 			}
-
-			seg->byte_count = htonl(MTHCA_INLINE_SEG | s);
-			size += align(s + sizeof *seg, 16) / 16;
 		} else {
 			struct mthca_data_seg *seg;
 
Index: libmthca/ChangeLog
===================================================================
--- libmthca/ChangeLog	(revision 4182)
+++ libmthca/ChangeLog	(working copy)
@@ -3,6 +3,9 @@
 	* src/qp.c (mthca_init_qp_indices): Set qp->sq.last and
 	qp->rq.last so that QP is fully reset when the indices are
 	reinited on transition to RESET state.
+	(mthca_tavor_post_send, mthca_arbel_post_send): Don't create an
+	inline send segment when a work request is posted that has the
+	inline flag set but no gather entries included.
 
 2005-11-09  Roland Dreier  <roland at cisco.com>