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Kernel/PCI: Don't hold spinlocks when doing fast device enumeration

Browse source 
Instead, hold the lock while we copy the contents to a stack-based
Vector then iterate on it without any locking.

Because we rely on heap allocations, we need to propagate errors back
in case of OOM condition, therefore, both PCI::enumerate API function
and PCI::Access::add_host_controller_and_enumerate_attached_devices use
now a ErrorOr<void> return value to propagate errors. OOM Error can only
occur when enumerating the m_device_identifiers vector under a spinlock
and trying to expand the temporary Vector which will be used locklessly
to actually iterate over the PCI::DeviceIdentifiers objects.
This commit is contained in:
Liav A 2022-02-04 19:48:13 +02:00 • committed by Andreas Kling
parent c0ed656c94
commit 3fb289e27d
14 changed files with 69 additions and 42 deletions
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4
Kernel/Devices/PCISerialDevice.cpp
View file

@ -15,7 +15,7 @@ static SerialDevice* s_the = nullptr;
UNMAP_AFTER_INIT void PCISerialDevice::detect()
{
size_t current_device_minor = 68;
PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
MUST(PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
for (auto& board_definition : board_definitions) {
if (board_definition.device_id != device_identifier.hardware_id())
continue;
@ -36,7 +36,7 @@ UNMAP_AFTER_INIT void PCISerialDevice::detect()
dmesgln("PCISerialDevice: Found {} @ {}", board_definition.name, device_identifier.address());
return;
}
});
}));
}
SerialDevice& PCISerialDevice::the()