Re: [RFC PATCH v3 02/20] PCI/PM: Add a power-state helper that tries the bus lock

[sashiko-bot@kernel.org]

> PCI error recovery can hold pci_bus_sem for reading while waiting for a
> lock held by a driver. If that driver also needs the bus read lock to
> bring a device to D0, a queued writer can block it. Recovery, the driver
> and the writer then all wait for each other.
> 
> Add pci_try_set_power_state(), which returns -EAGAIN if it cannot take
> the bus lock immediately. The caller can then release its locks. Once
> the bus lock is held, use pci_set_power_state_locked() for the transition.
> Keep the existing cases that need no power-state change. The transition
> itself can still sleep.
> 
> Callers that already hold the bus read lock must use the locked helper
> instead.
> 
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>

Sashiko has reviewed this patch and found no issues.

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