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Kernel: Factor out range allocation from Process::allocate_region*().

Browse source 
These functions were doing exactly the same thing for range allocation, so
share that code in an allocate_range() helper.

Region allocation will now also fail if range allocation fails, which means
that mmap() can actually fail without falling apart. Exciting times!
This commit is contained in:
Andreas Kling 2019-05-17 04:39:22 +02:00
parent 87b54a82c7
commit 6957825444
3 changed files with 20 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Kernel/FileSystem/FileDescriptor.cpp
View file

@ -346,6 +346,8 @@ KResultOr<Region*> FileDescriptor::mmap(Process& process, LinearAddress laddr, s
// FIXME: Implement mapping at a client-specified address. Most of the support is already in plcae.
ASSERT(laddr.as_ptr() == nullptr);
auto* region = process.allocate_file_backed_region(LinearAddress(), size, inode(), move(region_name), prot & PROT_READ, prot & PROT_WRITE);
if (!region)
return KResult(-ENOMEM);
region->page_in();
return region;
}

40
Kernel/Process.cpp
View file

@ -68,17 +68,20 @@ bool Process::in_group(gid_t gid) const
return m_gids.contains(gid);
}
Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name, bool is_readable, bool is_writable, bool commit)
Range Process::allocate_range(LinearAddress laddr, size_t size)
{
laddr.mask(PAGE_MASK);
size = PAGE_ROUND_UP(size);
Range range;
if (laddr.is_null())
range = m_range_allocator.allocate_anywhere(size);
else
range = m_range_allocator.allocate_specific(laddr, size);
return m_range_allocator.allocate_anywhere(size);
return m_range_allocator.allocate_specific(laddr, size);
}
Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name, bool is_readable, bool is_writable, bool commit)
{
auto range = allocate_range(laddr, size);
if (!range.is_valid())
return nullptr;
m_regions.append(adopt(*new Region(range, move(name), is_readable, is_writable)));
MM.map_region(*this, *m_regions.last());
if (commit)
@ -88,15 +91,9 @@ Region* Process::allocate_region(LinearAddress laddr, size_t size, String&& name
Region* Process::allocate_file_backed_region(LinearAddress laddr, size_t size, RetainPtr<Inode>&& inode, String&& name, bool is_readable, bool is_writable)
{
laddr.mask(PAGE_MASK);
size = PAGE_ROUND_UP(size);
Range range;
if (laddr.is_null())
range = m_range_allocator.allocate_anywhere(size);
else
range = m_range_allocator.allocate_specific(laddr, size);
auto range = allocate_range(laddr, size);
if (!range.is_valid())
return nullptr;
m_regions.append(adopt(*new Region(range, move(inode), move(name), is_readable, is_writable)));
MM.map_region(*this, *m_regions.last());
return m_regions.last().ptr();
@ -104,15 +101,9 @@ Region* Process::allocate_file_backed_region(LinearAddress laddr, size_t size, R
Region* Process::allocate_region_with_vmo(LinearAddress laddr, size_t size, Retained<VMObject>&& vmo, size_t offset_in_vmo, String&& name, bool is_readable, bool is_writable)
{
laddr.mask(PAGE_MASK);
size = PAGE_ROUND_UP(size);
Range range;
if (laddr.is_null())
range = m_range_allocator.allocate_anywhere(size);
else
range = m_range_allocator.allocate_specific(laddr, size);
auto range = allocate_range(laddr, size);
if (!range.is_valid())
return nullptr;
offset_in_vmo &= PAGE_MASK;
size = ceil_div(size, PAGE_SIZE) * PAGE_SIZE;
m_regions.append(adopt(*new Region(range, move(vmo), offset_in_vmo, move(name), is_readable, is_writable)));
@ -328,6 +319,7 @@ int Process::do_exec(String path, Vector<String> arguments, Vector<String> envir
vmo->set_name("ELF image");
#endif
RetainPtr<Region> region = allocate_region_with_vmo(LinearAddress(), descriptor->metadata().size, vmo.copy_ref(), 0, "executable", true, false);
ASSERT(region);
if (this != &current->process()) {
// FIXME: Don't force-load the entire executable at once, let the on-demand pager take care of it.

2
Kernel/Process.h
View file

@ -258,6 +258,8 @@ private:
Process(String&& name, uid_t, gid_t, pid_t ppid, RingLevel, RetainPtr<Inode>&& cwd = nullptr, RetainPtr<Inode>&& executable = nullptr, TTY* = nullptr, Process* fork_parent = nullptr);
Range allocate_range(LinearAddress, size_t);
int do_exec(String path, Vector<String> arguments, Vector<String> environment);
ssize_t do_write(FileDescriptor&, const byte*, int data_size);