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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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5
Kernel/GlobalProcessExposed.cpp
View file

@ -5,6 +5,7 @@
*/
#include <AK/JsonObjectSerializer.h>
#include <AK/Try.h>
#include <AK/UBSanitizer.h>
#include <Kernel/Arch/x86/InterruptDisabler.h>
#include <Kernel/Arch/x86/ProcessorInfo.h>
@ -680,7 +681,7 @@ private:
{
auto array = TRY(JsonArraySerializer<>::try_create(builder));
ErrorOr<void> result; // FIXME: Make this nicer
PCI::enumerate([&array, &result](PCI::DeviceIdentifier const& device_identifier) {
TRY(PCI::enumerate([&array, &result](PCI::DeviceIdentifier const& device_identifier) {
if (result.is_error())
return;
result = ([&]() -> ErrorOr<void> {
@ -699,7 +700,7 @@ private:
TRY(obj.finish());
return {};
})();
});
}));
TRY(result);
TRY(array.finish());
return {};