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Kernel: Handle multiple regions in sys$msync

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Hendiadyoin1 2022-06-18 18:38:31 +02:00 • committed by Andreas Kling
parent d783389877
commit 10d9bb93be
1 changed files with 26 additions and 12 deletions
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38
Kernel/Syscalls/mmap.cpp
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@ -571,23 +571,37 @@ ErrorOr<FlatPtr> Process::sys$msync(Userspace<void*> address, size_t size, int f
// Note: This is not specified
auto rounded_size = TRY(Memory::page_round_up(size));
// FIXME: We probably want to sync all mappings in the address+size range.
auto* region = address_space().find_region_containing(Memory::VirtualRange { address.vaddr(), rounded_size });
auto regions = TRY(address_space().find_regions_intersecting(Memory::VirtualRange { address.vaddr(), rounded_size }));
// All regions from address upto address+size shall be mapped
if (!region)
if (regions.is_empty())
return ENOMEM;
auto& vmobject = region->vmobject();
if (!vmobject.is_shared_inode())
return 0;
size_t total_intersection_size = 0;
Memory::VirtualRange range_to_sync { address.vaddr(), rounded_size };
for (auto const* region : regions) {
// Region was not mapped
if (!region->is_mmap())
return ENOMEM;
total_intersection_size += region->range().intersect(range_to_sync).size();
}
// Part of the indicated range was not mapped
if (total_intersection_size != size)
return ENOMEM;
off_t offset = region->offset_in_vmobject() + address.ptr() - region->range().base().get();
for (auto* region : regions) {
auto& vmobject = region->vmobject();
if (!vmobject.is_shared_inode())
continue;
auto& inode_vmobject = static_cast<Memory::SharedInodeVMObject&>(vmobject);
// FIXME: Handle MS_ASYNC
TRY(inode_vmobject.sync(offset / PAGE_SIZE, size / PAGE_SIZE));
// FIXME: Handle MS_INVALIDATE
// FIXME: If msync() causes any write to a file, the file's st_ctime and st_mtime fields shall be marked for update.
off_t offset = region->offset_in_vmobject() + address.ptr() - region->range().base().get();
auto& inode_vmobject = static_cast<Memory::SharedInodeVMObject&>(vmobject);
// FIXME: If multiple regions belong to the same vmobject we might want to coalesce these writes
// FIXME: Handle MS_ASYNC
TRY(inode_vmobject.sync(offset / PAGE_SIZE, rounded_size / PAGE_SIZE));
// FIXME: Handle MS_INVALIDATE
// FIXME: If msync() causes any write to a file, the file's st_ctime and st_mtime fields shall be marked for update.
}
return 0;
}