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Code Issues Releases Wiki Activity

ircd::ctx: Fixes and assertions for shared_mutex upgrade lockable semantics.

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This commit is contained in:
Jason Volk 2020-05-01 14:08:29 -07:00
parent 926795f01a
commit a776565ce0
1 changed files with 35 additions and 13 deletions
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48
include/ircd/ctx/shared_mutex.h
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@ -120,28 +120,42 @@ noexcept
inline void
ircd::ctx::shared_mutex::unlock_upgrade_and_lock_shared()
{
++s;
assert(u == current);
assert(s >= 0);
u = nullptr;
++s;
q.notify_one();
}
inline void
ircd::ctx::shared_mutex::unlock_upgrade_and_lock()
{
assert(u == current);
q.wait([this]
{
return can_lock();
});
s = std::numeric_limits<decltype(s)>::min();
u = nullptr;
}
inline void
ircd::ctx::shared_mutex::unlock_and_lock_upgrade()
{
assert(u == current);
assert(s == std::numeric_limits<decltype(s)>::min());
s = 0;
u = current;
}
inline void
ircd::ctx::shared_mutex::unlock_and_lock_shared()
{
assert(u == current);
assert(s == std::numeric_limits<decltype(s)>::min());
s = 1;
q.notify_one();
}
@ -149,6 +163,8 @@ ircd::ctx::shared_mutex::unlock_and_lock_shared()
inline void
ircd::ctx::shared_mutex::unlock_upgrade()
{
assert(u == current);
u = nullptr;
q.notify_one();
}
@ -156,6 +172,8 @@ ircd::ctx::shared_mutex::unlock_upgrade()
inline void
ircd::ctx::shared_mutex::unlock_shared()
{
assert(s > 0);
--s;
q.notify_one();
}
@ -163,6 +181,9 @@ ircd::ctx::shared_mutex::unlock_shared()
inline void
ircd::ctx::shared_mutex::unlock()
{
assert(u == current);
assert(s == std::numeric_limits<decltype(s)>::min());
s = 0;
q.notify_all();
}
@ -218,7 +239,6 @@ ircd::ctx::shared_mutex::try_unlock_upgrade_and_lock()
if(!try_lock())
return false;
u = nullptr;
return true;
}
@ -238,7 +258,9 @@ ircd::ctx::shared_mutex::try_unlock_shared_and_lock()
if(s != 1)
return false;
s = 1;
assert(!u);
u = current;
s = std::numeric_limits<decltype(s)>::min();
return true;
}
@ -272,6 +294,7 @@ ircd::ctx::shared_mutex::lock()
return can_lock();
});
u = current;
s = std::numeric_limits<decltype(s)>::min();
}
@ -345,7 +368,10 @@ ircd::ctx::shared_mutex::try_lock_until(time_point&& tp)
};
if(can_lock)
{
u = current;
s = std::numeric_limits<decltype(s)>::min();
}
return can_lock;
}
@ -373,6 +399,7 @@ ircd::ctx::shared_mutex::try_lock()
{
if(can_lock())
{
u = current;
s = std::numeric_limits<decltype(s)>::min();
return true;
}
@ -383,13 +410,8 @@ inline bool
ircd::ctx::shared_mutex::can_lock_upgrade()
const
{
if(s < 0)
return false;
if(u)
return false;
return true;
assert(u || can_lock_shared());
return !u;
}
inline bool
@ -403,7 +425,7 @@ inline bool
ircd::ctx::shared_mutex::can_lock()
const
{
return s == 0;
return s == 0 && (!u || u == current);
}
inline size_t