Kernel: Wrap RegionTree objects in SpinlockProtected

This makes locking them much more straightforward, and we can remove
a bunch of confusing use of AddressSpace::m_lock. That lock will also
be converted to use of SpinlockProtected in a subsequent patch.

1 files changed, 118 insertions, 112 deletions

diff --git a/Kernel/Memory/AddressSpace.cpp b/Kernel/Memory/AddressSpace.cpp
index cc2a765a40..f215e572cd 100644
--- a/Kernel/Memory/AddressSpace.cpp
+++ b/Kernel/Memory/AddressSpace.cpp
@@ -25,7 +25,7 @@ ErrorOr<NonnullOwnPtr<AddressSpace>> AddressSpace::try_create(AddressSpace const
 
     VirtualRange total_range = [&]() -> VirtualRange {
         if (parent)
-            return parent->m_region_tree.total_range();
+            return parent->m_total_range;
         constexpr FlatPtr userspace_range_base = USER_RANGE_BASE;
         FlatPtr const userspace_range_ceiling = USER_RANGE_CEILING;
         size_t random_offset = (get_fast_random<u8>() % 2 * MiB) & PAGE_MASK;
@@ -40,7 +40,8 @@ ErrorOr<NonnullOwnPtr<AddressSpace>> AddressSpace::try_create(AddressSpace const
 
 AddressSpace::AddressSpace(NonnullLockRefPtr<PageDirectory> page_directory, VirtualRange total_range)
     : m_page_directory(move(page_directory))
-    , m_region_tree(total_range)
+    , m_total_range(total_range)
+    , m_region_tree(LockRank::None, total_range)
 {
 }
 
@@ -148,8 +149,10 @@ ErrorOr<Region*> AddressSpace::try_allocate_split_region(Region const& source_re
         if (source_region.should_cow(page_offset_in_source_region + i))
             TRY(new_region->set_should_cow(i, true));
     }
-    SpinlockLocker locker(m_lock);
-    TRY(m_region_tree.place_specifically(*new_region, range));
+    TRY(m_region_tree.with([&](auto& region_tree) -> ErrorOr<void> {
+        TRY(region_tree.place_specifically(*new_region, range));
+        return {};
+    }));
     return new_region.leak_ptr();
 }
 
@@ -164,11 +167,14 @@ ErrorOr<Region*> AddressSpace::allocate_region(RandomizeVirtualAddress randomize
         region_name = TRY(KString::try_create(name));
     auto vmobject = TRY(AnonymousVMObject::try_create_with_size(size, strategy));
     auto region = TRY(Region::create_unplaced(move(vmobject), 0, move(region_name), prot_to_region_access_flags(prot)));
-    if (requested_address.is_null()) {
-        TRY(m_region_tree.place_anywhere(*region, randomize_virtual_address, size, alignment));
-    } else {
-        TRY(m_region_tree.place_specifically(*region, VirtualRange { requested_address, size }));
-    }
+    TRY(m_region_tree.with([&](auto& region_tree) -> ErrorOr<void> {
+        if (requested_address.is_null()) {
+            TRY(region_tree.place_anywhere(*region, randomize_virtual_address, size, alignment));
+        } else {
+            TRY(region_tree.place_specifically(*region, VirtualRange { requested_address, size }));
+        }
+        return {};
+    }));
     TRY(region->map(page_directory(), ShouldFlushTLB::No));
     return region.leak_ptr();
 }
@@ -204,29 +210,29 @@ ErrorOr<Region*> AddressSpace::allocate_region_with_vmobject(RandomizeVirtualAdd
 
     auto region = TRY(Region::create_unplaced(move(vmobject), offset_in_vmobject, move(region_name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared));
 
-    SpinlockLocker locker(m_lock);
-
-    if (requested_address.is_null())
-        TRY(m_region_tree.place_anywhere(*region, randomize_virtual_address, size, alignment));
-    else
-        TRY(m_region_tree.place_specifically(*region, VirtualRange { VirtualAddress { requested_address }, size }));
-
-    ArmedScopeGuard remove_region_from_tree_on_failure = [this, &region]() {
-        // At this point the region is already part of the Process region tree, so we have to make sure
-        // we remove it from the tree before returning an error, or else the Region tree will contain
-        // a dangling pointer to the free'd Region instance
-        m_region_tree.remove(*region);
-    };
-
-    if (prot == PROT_NONE) {
-        // For PROT_NONE mappings, we don't have to set up any page table mappings.
-        // We do still need to attach the region to the page_directory though.
-        region->set_page_directory(page_directory());
-    } else {
-        TRY(region->map(page_directory(), ShouldFlushTLB::No));
-    }
-    remove_region_from_tree_on_failure.disarm();
-    return region.leak_ptr();
+    return m_region_tree.with([&](auto& region_tree) -> ErrorOr<Region*> {
+        if (requested_address.is_null())
+            TRY(region_tree.place_anywhere(*region, randomize_virtual_address, size, alignment));
+        else
+            TRY(region_tree.place_specifically(*region, VirtualRange { VirtualAddress { requested_address }, size }));
+
+        ArmedScopeGuard remove_region_from_tree_on_failure = [&] {
+            // At this point the region is already part of the Process region tree, so we have to make sure
+            // we remove it from the tree before returning an error, or else the Region tree will contain
+            // a dangling pointer to the free'd Region instance
+            region_tree.remove(*region);
+        };
+
+        if (prot == PROT_NONE) {
+            // For PROT_NONE mappings, we don't have to set up any page table mappings.
+            // We do still need to attach the region to the page_directory though.
+            region->set_page_directory(page_directory());
+        } else {
+            TRY(region->map(page_directory(), ShouldFlushTLB::No));
+        }
+        remove_region_from_tree_on_failure.disarm();
+        return region.leak_ptr();
+    });
 }
 
 void AddressSpace::deallocate_region(Region& region)
@@ -236,16 +242,14 @@ void AddressSpace::deallocate_region(Region& region)
 
 NonnullOwnPtr<Region> AddressSpace::take_region(Region& region)
 {
-    auto did_remove = m_region_tree.remove(region);
+    auto did_remove = m_region_tree.with([&](auto& region_tree) { return region_tree.remove(region); });
     VERIFY(did_remove);
     return NonnullOwnPtr { NonnullOwnPtr<Region>::Adopt, region };
 }
 
 Region* AddressSpace::find_region_from_range(VirtualRange const& range)
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-    auto* found_region = m_region_tree.regions().find(range.base().get());
+    auto* found_region = m_region_tree.with([&](auto& region_tree) { return region_tree.regions().find(range.base().get()); });
     if (!found_region)
         return nullptr;
     auto& region = *found_region;
@@ -257,7 +261,9 @@ Region* AddressSpace::find_region_from_range(VirtualRange const& range)
 
 Region* AddressSpace::find_region_containing(VirtualRange const& range)
 {
-    return m_region_tree.find_region_containing(range);
+    return m_region_tree.with([&](auto& region_tree) {
+        return region_tree.find_region_containing(range);
+    });
 }
 
 ErrorOr<Vector<Region*, 4>> AddressSpace::find_regions_intersecting(VirtualRange const& range)
@@ -265,24 +271,23 @@ ErrorOr<Vector<Region*, 4>> AddressSpace::find_regions_intersecting(VirtualRange
     Vector<Region*, 4> regions = {};
     size_t total_size_collected = 0;
 
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-
-    auto* found_region = m_region_tree.regions().find_largest_not_above(range.base().get());
-    if (!found_region)
-        return regions;
-    for (auto iter = m_region_tree.regions().begin_from(*found_region); !iter.is_end(); ++iter) {
-        auto const& iter_range = (*iter).range();
-        if (iter_range.base() < range.end() && iter_range.end() > range.base()) {
-            TRY(regions.try_append(&*iter));
-
-            total_size_collected += (*iter).size() - iter_range.intersect(range).size();
-            if (total_size_collected == range.size())
-                break;
+    return m_region_tree.with([&](auto& region_tree) -> ErrorOr<Vector<Region*, 4>> {
+        auto* found_region = region_tree.regions().find_largest_not_above(range.base().get());
+        if (!found_region)
+            return regions;
+        for (auto iter = region_tree.regions().begin_from(*found_region); !iter.is_end(); ++iter) {
+            auto const& iter_range = (*iter).range();
+            if (iter_range.base() < range.end() && iter_range.end() > range.base()) {
+                TRY(regions.try_append(&*iter));
+
+                total_size_collected += (*iter).size() - iter_range.intersect(range).size();
+                if (total_size_collected == range.size())
+                    break;
+            }
         }
-    }
 
-    return regions;
+        return regions;
+    });
 }
 
 // Carve out a virtual address range from a region and return the two regions on either side
@@ -316,61 +321,63 @@ void AddressSpace::dump_regions()
     dbgln("BEGIN{}         END{}        SIZE{}       ACCESS NAME",
         addr_padding, addr_padding, addr_padding);
 
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-
-    for (auto const& region : m_region_tree.regions()) {
-        dbgln("{:p} -- {:p} {:p} {:c}{:c}{:c}{:c}{:c}{:c} {}", region.vaddr().get(), region.vaddr().offset(region.size() - 1).get(), region.size(),
-            region.is_readable() ? 'R' : ' ',
-            region.is_writable() ? 'W' : ' ',
-            region.is_executable() ? 'X' : ' ',
-            region.is_shared() ? 'S' : ' ',
-            region.is_stack() ? 'T' : ' ',
-            region.is_syscall_region() ? 'C' : ' ',
-            region.name());
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            dbgln("{:p} -- {:p} {:p} {:c}{:c}{:c}{:c}{:c}{:c} {}", region.vaddr().get(), region.vaddr().offset(region.size() - 1).get(), region.size(),
+                region.is_readable() ? 'R' : ' ',
+                region.is_writable() ? 'W' : ' ',
+                region.is_executable() ? 'X' : ' ',
+                region.is_shared() ? 'S' : ' ',
+                region.is_stack() ? 'T' : ' ',
+                region.is_syscall_region() ? 'C' : ' ',
+                region.name());
+        }
+    });
     MM.dump_kernel_regions();
 }
 
 void AddressSpace::remove_all_regions(Badge<Process>)
 {
     VERIFY(Thread::current() == g_finalizer);
-    SpinlockLocker locker(m_lock);
     {
         SpinlockLocker pd_locker(m_page_directory->get_lock());
         SpinlockLocker mm_locker(s_mm_lock);
-        SpinlockLocker tree_locker(m_region_tree.get_lock());
-        for (auto& region : m_region_tree.regions())
-            region.unmap_with_locks_held(ShouldFlushTLB::No, pd_locker, mm_locker);
+        m_region_tree.with([&](auto& region_tree) {
+            for (auto& region : region_tree.regions())
+                region.unmap_with_locks_held(ShouldFlushTLB::No, pd_locker, mm_locker);
+        });
     }
 
-    m_region_tree.delete_all_regions_assuming_they_are_unmapped();
+    m_region_tree.with([&](auto& region_tree) {
+        region_tree.delete_all_regions_assuming_they_are_unmapped();
+    });
 }
 
 size_t AddressSpace::amount_dirty_private() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     // FIXME: This gets a bit more complicated for Regions sharing the same underlying VMObject.
     //        The main issue I'm thinking of is when the VMObject has physical pages that none of the Regions are mapping.
     //        That's probably a situation that needs to be looked at in general.
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
-        if (!region.is_shared())
-            amount += region.amount_dirty();
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            if (!region.is_shared())
+                amount += region.amount_dirty();
+        }
+    });
     return amount;
 }
 
 ErrorOr<size_t> AddressSpace::amount_clean_inode() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
-    HashTable<InodeVMObject const*> vmobjects;
-    for (auto const& region : m_region_tree.regions()) {
-        if (region.vmobject().is_inode())
-            TRY(vmobjects.try_set(&static_cast<InodeVMObject const&>(region.vmobject())));
-    }
+    HashTable<LockRefPtr<InodeVMObject>> vmobjects;
+    TRY(m_region_tree.with([&](auto& region_tree) -> ErrorOr<void> {
+        for (auto const& region : region_tree.regions()) {
+            if (region.vmobject().is_inode())
+                TRY(vmobjects.try_set(&static_cast<InodeVMObject const&>(region.vmobject())));
+        }
+        return {};
+    }));
     size_t amount = 0;
     for (auto& vmobject : vmobjects)
         amount += vmobject->amount_clean();
@@ -379,69 +386,68 @@ ErrorOr<size_t> AddressSpace::amount_clean_inode() const
 
 size_t AddressSpace::amount_virtual() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
-        amount += region.size();
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            amount += region.size();
+        }
+    });
     return amount;
 }
 
 size_t AddressSpace::amount_resident() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     // FIXME: This will double count if multiple regions use the same physical page.
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
-        amount += region.amount_resident();
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            amount += region.amount_resident();
+        }
+    });
     return amount;
 }
 
 size_t AddressSpace::amount_shared() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     // FIXME: This will double count if multiple regions use the same physical page.
     // FIXME: It doesn't work at the moment, since it relies on PhysicalPage ref counts,
     //        and each PhysicalPage is only reffed by its VMObject. This needs to be refactored
     //        so that every Region contributes +1 ref to each of its PhysicalPages.
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
-        amount += region.amount_shared();
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            amount += region.amount_shared();
+        }
+    });
     return amount;
 }
 
 size_t AddressSpace::amount_purgeable_volatile() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
-        if (!region.vmobject().is_anonymous())
-            continue;
-        auto const& vmobject = static_cast<AnonymousVMObject const&>(region.vmobject());
-        if (vmobject.is_purgeable() && vmobject.is_volatile())
-            amount += region.amount_resident();
-    }
+    m_region_tree.with([&](auto& region_tree) {
+        for (auto const& region : region_tree.regions()) {
+            if (!region.vmobject().is_anonymous())
+                continue;
+            auto const& vmobject = static_cast<AnonymousVMObject const&>(region.vmobject());
+            if (vmobject.is_purgeable() && vmobject.is_volatile())
+                amount += region.amount_resident();
+        }
+    });
     return amount;
 }
 
 size_t AddressSpace::amount_purgeable_nonvolatile() const
 {
-    SpinlockLocker lock(m_lock);
-    SpinlockLocker tree_locker(m_region_tree.get_lock());
     size_t amount = 0;
-    for (auto const& region : m_region_tree.regions()) {
+    m_region_tree.with([&](auto& region_tree) {
+    for (auto const& region : region_tree.regions()) {
         if (!region.vmobject().is_anonymous())
             continue;
         auto const& vmobject = static_cast<AnonymousVMObject const&>(region.vmobject());
         if (vmobject.is_purgeable() && !vmobject.is_volatile())
             amount += region.amount_resident();
-    }
+    } });
     return amount;
 }