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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/Bus/VirtIO/Device.cpp
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@ -18,7 +18,7 @@ UNMAP_AFTER_INIT void detect()
{
if (kernel_command_line().disable_virtio())
return;
PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
MUST(PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
if (device_identifier.hardware_id().is_null())
return;
// TODO: We should also be checking that the device_id is in between 0x1000 - 0x107F inclusive
@ -43,7 +43,7 @@ UNMAP_AFTER_INIT void detect()
dbgln_if(VIRTIO_DEBUG, "VirtIO: Unknown VirtIO device with ID: {}", device_identifier.hardware_id().device_id);
break;
}
});
}));
}
static StringView determine_device_class(PCI::DeviceIdentifier const& device_identifier)