Back-patch assorted latch-related fixes.

Fix a whole bunch of signal handlers that had been hacked to do things that
might change errno, without adding the necessary save/restore logic for
errno.  Also make some minor fixes in unix_latch.c, and clean up bizarre
and unsafe scheme for disowning the process's latch.  While at it, rename
the PGPROC latch field to procLatch for consistency with 9.2.

Issues noted while reviewing a patch by Peter Geoghegan.

1 files changed, 5 insertions, 12 deletions

diff --git a/src/backend/replication/syncrep.c b/src/backend/replication/syncrep.c
index 8713b9700dc..6463420cd85 100644
--- a/src/backend/replication/syncrep.c
+++ b/src/backend/replication/syncrep.c
@@ -111,9 +111,6 @@ SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
 	Assert(SHMQueueIsDetached(&(MyProc->syncRepLinks)));
 	Assert(WalSndCtl != NULL);
 
-	/* Reset the latch before adding ourselves to the queue. */
-	ResetLatch(&MyProc->waitLatch);
-
 	LWLockAcquire(SyncRepLock, LW_EXCLUSIVE);
 	Assert(MyProc->syncRepState == SYNC_REP_NOT_WAITING);
 
@@ -167,7 +164,7 @@ SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
 		int			syncRepState;
 
 		/* Must reset the latch before testing state. */
-		ResetLatch(&MyProc->waitLatch);
+		ResetLatch(&MyProc->procLatch);
 
 		/*
 		 * Try checking the state without the lock first.  There's no
@@ -247,11 +244,11 @@ SyncRepWaitForLSN(XLogRecPtr XactCommitLSN)
 		}
 
 		/*
-		 * Wait on latch for up to 60 seconds. This allows us to check for
+		 * Wait on latch for up to 10 seconds. This allows us to check for
 		 * cancel/die signal or postmaster death regularly while waiting. Note
 		 * that timeout here does not necessarily release from loop.
 		 */
-		WaitLatch(&MyProc->waitLatch, 60000L);
+		WaitLatch(&MyProc->procLatch, 10000L);
 	}
 
 	/*
@@ -322,7 +319,7 @@ SyncRepCancelWait(void)
 }
 
 void
-SyncRepCleanupAtProcExit(int code, Datum arg)
+SyncRepCleanupAtProcExit(void)
 {
 	if (!SHMQueueIsDetached(&(MyProc->syncRepLinks)))
 	{
@@ -330,8 +327,6 @@ SyncRepCleanupAtProcExit(int code, Datum arg)
 		SHMQueueDelete(&(MyProc->syncRepLinks));
 		LWLockRelease(SyncRepLock);
 	}
-
-	DisownLatch(&MyProc->waitLatch);
 }
 
 /*
@@ -560,9 +555,7 @@ SyncRepWakeQueue(bool all)
 		/*
 		 * Wake only when we have set state and removed from queue.
 		 */
-		Assert(SHMQueueIsDetached(&(thisproc->syncRepLinks)));
-		Assert(thisproc->syncRepState == SYNC_REP_WAIT_COMPLETE);
-		SetLatch(&(thisproc->waitLatch));
+		SetLatch(&(thisproc->procLatch));
 
 		numprocs++;
 	}