[hurd,commited] hurd: Fix _hurd_select for single fd sets

[Samuel Thibault]

From: Richard Braun <address@hidden>

The function attempts to optimize this case by performing one IPC system
call with the timeout included among the parameters, but in the absence
of a reply, it will call mach_msg again with the same timeout later,
effectively doubling the total timeout of the select/poll call.

Remove this optimization for the time being.

        * hurd/hurdselect.c (_hurd_select): Always call __io_select with no
        timeout.
---
 ChangeLog         | 5 +++++
 hurd/hurdselect.c | 5 +----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 87d43d425e..06c8852c95 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2019-08-30  Richard Braun <address@hidden>
+
+       * hurd/hurdselect.c (_hurd_select): Always call __io_select with no
+       timeout.
+
 2019-08-29  Mihailo Stojanovic  <address@hidden>
 
        * elf/dl-addr.c (determine_info): Calculate the symbol index
diff --git a/hurd/hurdselect.c b/hurd/hurdselect.c
index 6997b2b73b..a5e6e26b9a 100644
--- a/hurd/hurdselect.c
+++ b/hurd/hurdselect.c
@@ -236,10 +236,7 @@ _hurd_select (int nfds,
          {
            int type = d[i].type;
            d[i].reply_port = __mach_reply_port ();
-           err = __io_select (d[i].io_port, d[i].reply_port,
-                              /* Poll only if there's a single descriptor.  */
-                              (firstfd == lastfd) ? to : 0,
-                              &type);
+           err = __io_select (d[i].io_port, d[i].reply_port, 0, &type);
            switch (err)
              {
              case MACH_RCV_TIMED_OUT:
-- 
2.23.0.rc1