[kernel] Remove obsolete 'mappings' list from VMAs

The vm_area_shared type of VMA used to track mappings in a separate
array, which doubled information and wasted space. This was no longer
used, and is now removed.

src/kernel/objects/vm_area.cpp

@@ -52,145 +52,6 @@ vm_area_shared::~vm_area_shared()
 {
 }
 
-size_t
-vm_area_shared::overlaps(uintptr_t offset, size_t pages, size_t *count)
-{
-	size_t first = 0;
-	size_t n = 0;
-
-	uintptr_t end = offset + pages * frame_size;
-	for (size_t i = 0; i < m_mappings.count(); ++i) {
-		mapping &m = m_mappings[i];
-		uintptr_t map_end = m.offset + m.count * frame_size;
-		if (offset < map_end && end > m.offset) {
-			if (!first) first = i;
-			++n;
-		} else if (n) {
-			break;
-		}
-	}
-
-	if (count) *count = n;
-	return first;
-}
-
-void
-vm_area_shared::commit(uintptr_t phys, uintptr_t offset, size_t count)
-{
-	size_t n = 0;
-	size_t o = overlaps(offset, count, &n);
-
-	// Mapping overlaps not allowed
-	if (n) return;
-
-	m_mapper.map(offset, count, phys);
-
-	o = m_mappings.sorted_insert({
-		.offset = offset,
-		.count = count,
-		.phys = phys});
-	n = 1;
-
-	// Try to expand to abutting similar areas
-	if (o > 0 &&
-		m_mappings[o-1].end() == offset &&
-		m_mappings[o-1].phys_end() == phys) {
-		--o;
-		++n;
-	}
-
-	uintptr_t end = offset + count * frame_size;
-	uintptr_t pend = phys + count * frame_size;
-
-	if (o + n < m_mappings.count() &&
-		end == m_mappings[o+n].offset &&
-		m_mappings[o-1].phys == pend) {
-		++n;
-	}
-
-	// Use the first overlap block as our new block
-	mapping &first = m_mappings[o];
-	mapping &last = m_mappings[o + n -1];
-
-	if (offset < first.offset)
-		first.offset = offset;
-
-	size_t diff =
-		(end > last.end() ? end : last.end()) -
-		first.offset;
-
-	first.count = memory::page_count(diff);
-
-	if (n > 1)
-		m_mappings.remove_at(o+1, n-1);
-
-	return;
-}
-
-void
-vm_area_shared::uncommit(uintptr_t offset, size_t count)
-{
-	size_t n = 0;
-	size_t o = overlaps(offset, count, &n);
-	if (!n) return;
-
-	m_mapper.unmap(offset, count);
-
-	mapping *first = &m_mappings[o];
-	mapping *last = &m_mappings[o+n-1];
-
-	uintptr_t end = offset + count * frame_size;
-
-	size_t leading = offset - first->offset;
-	size_t trailing = last->end() - end;
-
-	// if were entirely contained in one, we need to split it
-	if (leading && trailing && n == 1) {
-		size_t i = m_mappings.sorted_insert({
-			.offset = end,
-			.count = trailing / frame_size,
-			});
-		last = &m_mappings[i];
-		trailing = 0;
-
-		first->count -= last->count;
-		last->phys = first->phys + first->count * frame_size;
-	}
-
-	if (leading) {
-		size_t remove_pages = first->count; 
-		first->count = leading / frame_size;
-		remove_pages -= first->count;
-		m_mapper.unmap(first->end(), remove_pages);
-	}
-
-	if (trailing) {
-		uintptr_t remove_off = last->offset;
-		size_t remove_pages = last->count; 
-		last->offset = end;
-		last->count = trailing / frame_size;
-		remove_pages -= last->count;
-		m_mapper.unmap(remove_off, remove_pages);
-		last->phys += remove_pages * frame_size;
-	}
-
-	size_t delete_start = 0;
-	size_t delete_count = 0;
-	for (size_t i = o; i < o+n; ++i) {
-		mapping &m = m_mappings[i];
-		if (offset <= m.offset && end >= m.end()) {
-			if (!delete_count) delete_start = i;
-			++delete_count;
-			m_mapper.unmap(m.offset, m.count);
-		}
-	}
-
-	if (delete_count)
-		m_mappings.remove_at(delete_start, delete_count);
-
-	return;
-}
-
 
 vm_area_open::vm_area_open(size_t size, vm_space &space, vm_flags flags) :
 	m_mapper(*this, space),

src/kernel/objects/vm_area.h

@@ -100,28 +100,8 @@ public:
 	virtual vm_mapper & mapper() override { return m_mapper; }
 	virtual const vm_mapper & mapper() const override { return m_mapper; }
 
-	virtual void commit(uintptr_t phys, uintptr_t offset, size_t count) override;
-	virtual void uncommit(uintptr_t offset, size_t count) override;
-
 private:
 	vm_mapper_multi m_mapper;
-
-	struct mapping {
-		uintptr_t offset;
-		size_t count;
-		uintptr_t phys;
-
-		int compare(const struct mapping &o) const {
-			return offset > o.offset ? 1 : offset < o.offset ? -1 : 0;
-		}
-
-		inline uintptr_t end() const { return offset + count * memory::frame_size; }
-		inline uintptr_t phys_end() const { return phys + count * memory::frame_size; }
-	};
-
-	size_t overlaps(uintptr_t offset, size_t pages, size_t *count);
-
-	kutil::vector<mapping> m_mappings;
 };