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

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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/Bus/PCI/Access.h
View file

@ -7,6 +7,7 @@
#pragma once
#include <AK/Bitmap.h>
#include <AK/Try.h>
#include <AK/Vector.h>
#include <Kernel/Bus/PCI/Controller/HostController.h>
#include <Kernel/Bus/PCI/Definitions.h>
@ -21,7 +22,7 @@ public:
static bool initialize_for_multiple_pci_domains(PhysicalAddress mcfg_table);
static bool initialize_for_one_pci_domain();
void fast_enumerate(Function<void(DeviceIdentifier const&)>&) const;
ErrorOr<void> fast_enumerate(Function<void(DeviceIdentifier const&)>&) const;
void rescan_hardware();
static Access& the();
@ -39,7 +40,7 @@ public:
Spinlock const& scan_lock() const { return m_scan_lock; }
RecursiveSpinlock const& access_lock() const { return m_access_lock; }
void add_host_controller_and_enumerate_attached_devices(NonnullOwnPtr<HostController>, Function<void(DeviceIdentifier const&)> callback);
ErrorOr<void> add_host_controller_and_enumerate_attached_devices(NonnullOwnPtr<HostController>, Function<void(DeviceIdentifier const&)> callback);
private:
u8 read8_field(Address address, RegisterOffset field);