Linux did the same thing 18 years ago and their reasons for the change
are similar to ours - https://github.com/torvalds/linux/commit/7d12e78
Most interrupt handlers (i.e. IRQ handlers) never used the register
state reference anywhere so there's simply no need of passing it around.
I didn't measure the performance boost but surely this change can't make
things worse anyway.
This helps ensure no one accidentally accesses m_requests without first
locking it's spinlock. In fact this change fixed such a case, since
process_cq() implicitly assumed the caller locked the lock, which was
not the case for NVMePollQueue::submit_sqe().
Most of the actual logic is identical, with the only real difference
being that one wraps it with an async work item.
Merge the implementations to reduce duplications (which will also
require the fixes in the next commits to only be done once).
Introduce a new Struct Doorbell that encapsulates the mmio doorbell
register.
This commit does not introduce any functional changes and it is added
in preparation to adding shadow doorbell support.
This was the root cause of zombie processes showing up randomly and
disappearing after some disk activity, such as running shell commands -
The NVMeIO AsyncBlockDeviceRequest member simply held a pointer to a
Process object, therefore it could keep it alive a for a long time after
it ceased to actually function at all.
The Storage subsystem, like the Audio and HID subsystems, exposes Unix
device files (for example, in the /dev directory). To ensure consistency
across the repository, we should make the Storage subsystem to reside in
the Kernel/Devices directory like the two other mentioned subsystems.
