ubik: don't rely on timeout value after select()

The value of timeout after a select() call should be considered
undefined; relying on its value is not portable.
Since IOMGR_Select doesn't modify the timeout it is given, the
intention of the code seems to be to wait for gradually increasing
timeout values, starting at 50ms.  At least under Linux, the
timeout gets set to 0 by select() if it waited for the full specified
time, resulting in a much shorter maximum possible wait period.

Initialize the timeout value for each loop according to the existing
logic, to get consistent behaviour between the lwp and pthreaded code.

Reviewed-on: http://gerrit.openafs.org/4441
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 0b510fe30afb34202342364e96bd9030052e1567)

Change-Id: I24eb4d4b1f758f33e3517671cb576ff23e641fb3
Reviewed-on: http://gerrit.openafs.org/6282
Tested-by: Derrick Brashear <shadow@dementix.org>
Reviewed-by: Derrick Brashear <shadow@dementix.org>

diff --git a/src/ubik/recovery.c b/src/ubik/recovery.c
index 3ad7b9853db4c8af5231e4d4f4128631b6bc8081..f0b09ae6320269cc4259e8eee8cb7b845fc00ed4 100644 (file)
--- a/src/ubik/recovery.c
+++ b/src/ubik/recovery.c
@@ -776,17 +776,18 @@ urecovery_Interact(void *dummy)
            if (ubik_dbase->flags & DBWRITING) {
                struct timeval tv;
                int safety = 0;
-               tv.tv_sec = 0;
-               tv.tv_usec = 50000;
+               long cur_usec = 50000;
                while ((ubik_dbase->flags & DBWRITING) && (safety < 500)) {
                    DBRELE(ubik_dbase);
                    /* sleep for a little while */
+                   tv.tv_sec = 0;
+                   tv.tv_usec = cur_usec;
 #ifdef AFS_PTHREAD_ENV
                    select(0, 0, 0, 0, &tv);
 #else
                    IOMGR_Select(0, 0, 0, 0, &tv);
 #endif
-                   tv.tv_usec += 10000;
+                   cur_usec += 10000;
                    safety++;
                    DBHOLD(ubik_dbase);
                }