sock/posix: Fix sendmsg_idx rollover for zcopy

If the idx gets to UINT32_MAX we need to ensure it doesn't wrap around
before we check if we're done iterating.

This is a backport from 23.05.
Original commit e351b19.

Signed-off-by: Dmitry Savitskiy <[email protected]>

module/sock/posix/posix.c

@@ -686,21 +686,30 @@ _sock_check_zcopy(struct spdk_sock *sock)
 		 * we encounter one match we can stop looping as soon as a
 		 * non-match is found.
 		 */
-		for (idx = serr->ee_info; idx <= serr->ee_data; idx++) {
+		idx = serr->ee_info;
+		while (true) {
 			found = false;
 			TAILQ_FOREACH_SAFE(req, &sock->pending_reqs, internal.link, treq) {
 				if (req->internal.offset == idx) {
 					found = true;
-
 					rc = spdk_sock_request_put(sock, req, 0);
 					if (rc < 0) {
 						return rc;
 					}
-
 				} else if (found) {
 					break;
 				}
 			}
+
+			if (idx == serr->ee_data) {
+				break;
+			}
+
+			if (idx == UINT32_MAX) {
+				idx = 0;
+			} else {
+				idx++;
+			}
 		}
 	}