diff options
Diffstat (limited to 'Kernel')
| -rw-r--r-- | Kernel/FileSystem/Plan9FileSystem.cpp | 5 | ||||
| -rw-r--r-- | Kernel/FileSystem/Plan9FileSystem.h | 2 | ||||
| -rw-r--r-- | Kernel/Net/Routing.cpp | 6 | ||||
| -rw-r--r-- | Kernel/Thread.h | 40 | ||||
| -rw-r--r-- | Kernel/ThreadBlockers.cpp | 78 |
5 files changed, 92 insertions, 39 deletions
diff --git a/Kernel/FileSystem/Plan9FileSystem.cpp b/Kernel/FileSystem/Plan9FileSystem.cpp index 0b4da5b8e0..82eda6c882 100644 --- a/Kernel/FileSystem/Plan9FileSystem.cpp +++ b/Kernel/FileSystem/Plan9FileSystem.cpp @@ -425,6 +425,11 @@ bool Plan9FS::Blocker::unblock(u16 tag) return unblock(); } +bool Plan9FS::Blocker::setup_blocker() +{ + return add_to_blocker_set(m_fs.m_completion_blocker); +} + void Plan9FS::Blocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason) { { diff --git a/Kernel/FileSystem/Plan9FileSystem.h b/Kernel/FileSystem/Plan9FileSystem.h index 36148d536f..a101ebfe2f 100644 --- a/Kernel/FileSystem/Plan9FileSystem.h +++ b/Kernel/FileSystem/Plan9FileSystem.h @@ -87,8 +87,8 @@ private: , m_message(message) , m_completion(move(completion)) { - add_to_blocker_set(fs.m_completion_blocker); } + virtual bool setup_blocker() override; virtual StringView state_string() const override { return "Waiting"sv; } virtual Type blocker_type() const override { return Type::Plan9FS; } virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; diff --git a/Kernel/Net/Routing.cpp b/Kernel/Net/Routing.cpp index e756237de7..b4c6384463 100644 --- a/Kernel/Net/Routing.cpp +++ b/Kernel/Net/Routing.cpp @@ -25,6 +25,7 @@ public: virtual StringView state_string() const override { return "Routing (ARP)"sv; } virtual Type blocker_type() const override { return Type::Routing; } virtual bool should_block() override { return m_should_block; } + virtual bool setup_blocker() override; virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; @@ -86,8 +87,13 @@ ARPTableBlocker::ARPTableBlocker(IPv4Address ip_addr, Optional<MACAddress>& addr : m_ip_addr(ip_addr) , m_addr(addr) { +} + +bool ARPTableBlocker::setup_blocker() +{ if (!add_to_blocker_set(*s_arp_table_blocker_set)) m_should_block = false; + return m_should_block; } void ARPTableBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason) diff --git a/Kernel/Thread.h b/Kernel/Thread.h index 50534b7b6e..ffe37946a1 100644 --- a/Kernel/Thread.h +++ b/Kernel/Thread.h @@ -300,6 +300,7 @@ public: virtual Type blocker_type() const = 0; virtual const BlockTimeout& override_timeout(const BlockTimeout& timeout) { return timeout; } virtual bool can_be_interrupted() const { return true; } + virtual bool setup_blocker(); Thread& thread() { return m_thread; } @@ -523,11 +524,14 @@ public: virtual bool should_block() override { return !m_join_error && m_should_block; } virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; + virtual bool setup_blocker() override; + bool unblock(void*, bool); private: NonnullRefPtr<Thread> m_joinee; void*& m_joinee_exit_value; + KResult& m_try_join_result; bool m_join_error { false }; bool m_did_unblock { false }; bool m_should_block { true }; @@ -541,15 +545,13 @@ public: virtual Type blocker_type() const override { return Type::Queue; } virtual StringView state_string() const override { return m_block_reason.is_null() ? m_block_reason : "Queue"sv; } virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override { } - - virtual bool should_block() override - { - return m_should_block; - } + virtual bool should_block() override { return m_should_block; } + virtual bool setup_blocker() override; bool unblock(); protected: + WaitQueue& m_wait_queue; StringView m_block_reason; bool m_should_block { true }; bool m_did_unblock { false }; @@ -563,11 +565,8 @@ public: virtual Type blocker_type() const override { return Type::Futex; } virtual StringView state_string() const override { return "Futex"sv; } virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override { } - - virtual bool should_block() override - { - return m_should_block; - } + virtual bool should_block() override { return m_should_block; } + virtual bool setup_blocker() override; u32 bitset() const { return m_bitset; } @@ -582,7 +581,8 @@ public: bool unblock(bool force = false); protected: - u32 m_bitset; + FutexQueue& m_futex_queue; + u32 m_bitset { 0 }; u32 m_relock_flags { 0 }; bool m_should_block { true }; bool m_did_unblock { false }; @@ -627,6 +627,7 @@ public: virtual bool unblock(bool, void*) override; virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; + virtual bool setup_blocker() override; protected: explicit FileDescriptionBlocker(FileDescription&, BlockFlags, BlockFlags&); @@ -696,13 +697,14 @@ public: }; typedef Vector<FDInfo, FD_SETSIZE> FDVector; - explicit SelectBlocker(FDVector& fds); + explicit SelectBlocker(FDVector&); virtual ~SelectBlocker(); virtual bool unblock(bool, void*) override; virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; virtual void was_unblocked(bool) override; virtual StringView state_string() const override { return "Selecting"sv; } + virtual bool setup_blocker() override; private: size_t collect_unblocked_flags(); @@ -726,6 +728,7 @@ public: virtual bool should_block() override { return m_should_block; } virtual void will_unblock_immediately_without_blocking(UnblockImmediatelyReason) override; virtual void was_unblocked(bool) override; + virtual bool setup_blocker() override; bool unblock(Process& process, UnblockFlags flags, u8 signal, bool from_add_blocker); bool is_wait() const { return !(m_wait_options & WNOWAIT); } @@ -867,6 +870,12 @@ public: m_in_block = true; BlockerType blocker(forward<Args>(args)...); + if (!blocker.setup_blocker()) { + blocker.will_unblock_immediately_without_blocking(Blocker::UnblockImmediatelyReason::UnblockConditionAlreadyMet); + m_in_block = false; + return BlockResult::NotBlocked; + } + SpinlockLocker scheduler_lock(g_scheduler_lock); // Relaxed semantics are fine for timeout_unblocked because we // synchronize on the spin locks already. @@ -885,13 +894,6 @@ public: } m_blocker = &blocker; - if (!blocker.should_block()) { - // Don't block if the wake condition is already met - blocker.will_unblock_immediately_without_blocking(Blocker::UnblockImmediatelyReason::UnblockConditionAlreadyMet); - m_blocker = nullptr; - m_in_block = false; - return BlockResult::NotBlocked; - } auto& block_timeout = blocker.override_timeout(timeout); if (!block_timeout.is_infinite()) { diff --git a/Kernel/ThreadBlockers.cpp b/Kernel/ThreadBlockers.cpp index 149bcddad8..d6ae4ccff2 100644 --- a/Kernel/ThreadBlockers.cpp +++ b/Kernel/ThreadBlockers.cpp @@ -45,6 +45,11 @@ Thread::Blocker::~Blocker() m_blocker_set->remove_blocker(*this); } +bool Thread::Blocker::setup_blocker() +{ + return true; +} + void Thread::Blocker::begin_blocking(Badge<Thread>) { SpinlockLocker lock(m_lock); @@ -68,19 +73,23 @@ auto Thread::Blocker::end_blocking(Badge<Thread>, bool did_timeout) -> BlockResu Thread::JoinBlocker::JoinBlocker(Thread& joinee, KResult& try_join_result, void*& joinee_exit_value) : m_joinee(joinee) , m_joinee_exit_value(joinee_exit_value) + , m_try_join_result(try_join_result) { - { - // We need to hold our lock to avoid a race where try_join succeeds - // but the joinee is joining immediately - SpinlockLocker lock(m_lock); - try_join_result = joinee.try_join([&]() { - if (!add_to_blocker_set(joinee.m_join_blocker_set)) - m_should_block = false; - }); - m_join_error = try_join_result.is_error(); - if (m_join_error) +} + +bool Thread::JoinBlocker::setup_blocker() +{ + // We need to hold our lock to avoid a race where try_join succeeds + // but the joinee is joining immediately + SpinlockLocker lock(m_lock); + m_try_join_result = m_joinee->try_join([&]() { + if (!add_to_blocker_set(m_joinee->m_join_blocker_set)) m_should_block = false; - } + }); + m_join_error = m_try_join_result.is_error(); + if (m_join_error) + m_should_block = false; + return m_should_block; } void Thread::JoinBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason) @@ -114,10 +123,16 @@ bool Thread::JoinBlocker::unblock(void* value, bool from_add_blocker) } Thread::WaitQueueBlocker::WaitQueueBlocker(WaitQueue& wait_queue, StringView block_reason) - : m_block_reason(block_reason) + : m_wait_queue(wait_queue) + , m_block_reason(block_reason) { - if (!add_to_blocker_set(wait_queue)) +} + +bool Thread::WaitQueueBlocker::setup_blocker() +{ + if (!add_to_blocker_set(m_wait_queue)) m_should_block = false; + return m_should_block; } Thread::WaitQueueBlocker::~WaitQueueBlocker() @@ -138,10 +153,16 @@ bool Thread::WaitQueueBlocker::unblock() } Thread::FutexBlocker::FutexBlocker(FutexQueue& futex_queue, u32 bitset) - : m_bitset(bitset) + : m_futex_queue(futex_queue) + , m_bitset(bitset) +{ +} + +bool Thread::FutexBlocker::setup_blocker() { - if (!add_to_blocker_set(futex_queue)) + if (!add_to_blocker_set(m_futex_queue)) m_should_block = false; + return m_should_block; } Thread::FutexBlocker::~FutexBlocker() @@ -188,9 +209,14 @@ Thread::FileDescriptionBlocker::FileDescriptionBlocker(FileDescription& descript , m_flags(flags) , m_unblocked_flags(unblocked_flags) { +} + +bool Thread::FileDescriptionBlocker::setup_blocker() +{ m_unblocked_flags = BlockFlags::None; - if (!add_to_blocker_set(description.blocker_set())) + if (!add_to_blocker_set(m_blocked_description->blocker_set())) m_should_block = false; + return m_should_block; } bool Thread::FileDescriptionBlocker::unblock(bool from_add_blocker, void*) @@ -338,6 +364,10 @@ Thread::BlockResult Thread::SleepBlocker::block_result() Thread::SelectBlocker::SelectBlocker(FDVector& fds) : m_fds(fds) { +} + +bool Thread::SelectBlocker::setup_blocker() +{ for (auto& fd_entry : m_fds) { fd_entry.unblocked_flags = FileBlocker::BlockFlags::None; @@ -346,6 +376,7 @@ Thread::SelectBlocker::SelectBlocker(FDVector& fds) if (!fd_entry.description->blocker_set().add_blocker(*this, &fd_entry)) m_should_block = false; } + return m_should_block; } Thread::SelectBlocker::~SelectBlocker() @@ -590,7 +621,11 @@ Thread::WaitBlocker::WaitBlocker(int wait_options, idtype_t id_type, pid_t id, K , m_result(result) , m_should_block(!(m_wait_options & WNOHANG)) { - switch (id_type) { +} + +bool Thread::WaitBlocker::setup_blocker() +{ + switch (m_id_type) { case P_PID: { m_waitee = Process::from_pid(m_waitee_id); if (!m_waitee || m_waitee->ppid() != Process::current().pid()) { @@ -613,11 +648,16 @@ Thread::WaitBlocker::WaitBlocker(int wait_options, idtype_t id_type, pid_t id, K VERIFY_NOT_REACHED(); } + if (m_error) + return false; + + if (m_wait_options & WNOHANG) + return false; + // NOTE: unblock may be called within add_to_blocker_set, in which // case it means that we already have a match without having to block. // In that case add_to_blocker_set will return false. - if (m_error || !add_to_blocker_set(Process::current().wait_blocker_set())) - m_should_block = false; + return add_to_blocker_set(Process::current().wait_blocker_set()); } void Thread::WaitBlocker::will_unblock_immediately_without_blocking(UnblockImmediatelyReason reason) |