SERVER-37711 Revert commits related to lock yielding for prepared transactions on step down

This change reverts the following commits:

* SERVER-35870 Allow stepdown to work with prepared transactions (f96903979ac329a760e7b6f1bb5d8695d3daf2a7)
* SERVER-36913 Add functionality to LockManager for repl state transitions with prepared transactions (e65ff57e108ed69c46cc0b0ccbdd675663de2469)
* SERVER-35870 Allow more than one thread to block Session checkout at a time (9406af079a894bae80fbbec4703b04974bf84476)
* SERVER-35870 Add functionality to prevent Session checkouts & wait for all Sessions to be checked in (c6d90316d6b694e12426274c713a4a078e004fc5)

1 files changed, 0 insertions, 39 deletions

diff --git a/src/mongo/db/session_catalog.h b/src/mongo/db/session_catalog.h
index 2da89c2fb7a..addbb3c313c 100644
--- a/src/mongo/db/session_catalog.h
+++ b/src/mongo/db/session_catalog.h
@@ -58,8 +58,6 @@ class SessionCatalog {
     friend class ScopedCheckedOutSession;
 
 public:
-    class PreventCheckingOutSessionsBlock;
-
     SessionCatalog() = default;
     ~SessionCatalog();
 
@@ -152,47 +150,10 @@ private:
      */
     void _releaseSession(const LogicalSessionId& lsid);
 
-    bool _isSessionCheckoutAllowed() const {
-        return _preventSessionCheckoutRequests == 0;
-    };
-
-    // Protects members below.
     stdx::mutex _mutex;
 
     // Owns the Session objects for all current Sessions.
     LogicalSessionIdMap<std::shared_ptr<SessionRuntimeInfo>> _sessions;
-
-    // Count of the number of Sessions that are currently checked out.
-    uint32_t _numCheckedOutSessions{0};
-
-    // When >0 all Session checkout or creation requests will block.
-    uint32_t _preventSessionCheckoutRequests{0};
-
-    // Condition that is signaled when the number of checked out sessions goes to 0.
-    stdx::condition_variable _allSessionsCheckedInCond;
-
-    // Condition that is signaled when checking out Sessions becomes legal again after having
-    // previously been forbidden.
-    stdx::condition_variable _checkingOutSessionsAllowedCond;
-};
-
-/**
- * While this object is in scope, all requests to check out a Session will block.
- */
-class SessionCatalog::PreventCheckingOutSessionsBlock {
-    MONGO_DISALLOW_COPYING(PreventCheckingOutSessionsBlock);
-
-public:
-    explicit PreventCheckingOutSessionsBlock(SessionCatalog* sessionCatalog);
-    ~PreventCheckingOutSessionsBlock();
-
-    /**
-     * Waits until there are no Sessions checked out in the SessionCatalog.
-     */
-    void waitForAllSessionsToBeCheckedIn(OperationContext* opCtx);
-
-private:
-    SessionCatalog* _sessionCatalog{nullptr};
 };
 
 /**