[PATCH v2 0/9] deferred_probe_timeout logic clean up

Saravana Kannan via iommu
2022-06-01T07:07:17Z

This series is based on linux-next + these 2 small patches applies on top:
https://lore.kernel.org/lkml/20220526034609.480766-1-saravanak@google.com/

A lot of the deferred_probe_timeout logic is redundant with
fw_devlink=on. Also, enabling deferred_probe_timeout by default breaks
a few cases.

This series tries to delete the redundant logic, simplify the frameworks
that use driver_deferred_probe_check_state(), enable
deferred_probe_timeout=10 by default, and fixes the nfsroot failure
case.

The overall idea of this series is to replace the global behavior of
driver_deferred_probe_check_state() where all devices give up waiting on
supplier at the same time with a more granular behavior:

1. Devices with all their suppliers successfully probed by late_initcall
probe as usual and avoid unnecessary deferred probe attempts.

2. At or after late_initcall, in cases where boot would break because of
fw_devlink=on being strict about the ordering, we

a. Temporarily relax the enforcement to probe any unprobed devices
that can probe successfully in the current state of the system.
For example, when we boot with a NFS rootfs and no network device
has probed.
b. Go back to enforcing the ordering for any devices that haven't
probed.

3. After deferred probe timeout expires, we permanently give up waiting
on supplier devices without drivers. At this point, whatever devices
can probe without some of their optional suppliers end up probing.

In the case where module support is disabled, it's fairly
straightforward and all device probes are completed before the initcalls
are done.

Patches 1 to 3 are fairly straightforward and can probably be applied
right away.

Patches 4 to 6 are for fixing the NFS rootfs issue and setting the
default deferred_probe_timeout back to 10 seconds when modules are
enabled.

Patches 7 to 9 are further clean up of the deferred_probe_timeout logic
so that no framework has to know/care about deferred_probe_timeout.

Yoshihiro/Geert,

If you can test this patch series and confirm that the NFS root case
works, I'd really appreciate that.

Thanks,
Saravana

v1 -> v2:
Rewrote the NFS rootfs fix to be a lot less destructive on the
fw_devlink ordering for devices that don't end up probing during the
"best effort" attempt at probing all devices needed for a network rootfs

Saravana Kannan (9):
PM: domains: Delete usage of driver_deferred_probe_check_state()
pinctrl: devicetree: Delete usage of
driver_deferred_probe_check_state()
net: mdio: Delete usage of driver_deferred_probe_check_state()
driver core: Add wait_for_init_devices_probe helper function
net: ipconfig: Relax fw_devlink if we need to mount a network rootfs
Revert "driver core: Set default deferred_probe_timeout back to 0."
driver core: Set fw_devlink.strict=1 by default
iommu/of: Delete usage of driver_deferred_probe_check_state()
driver core: Delete driver_deferred_probe_check_state()

drivers/base/base.h | 1 +
drivers/base/core.c | 102 ++++++++++++++++++++++++++++++---
drivers/base/dd.c | 54 ++++++-----------
drivers/base/power/domain.c | 2 +-
drivers/iommu/of_iommu.c | 2 +-
drivers/net/mdio/fwnode_mdio.c | 4 +-
drivers/pinctrl/devicetree.c | 2 +-
include/linux/device/driver.h | 2 +-
net/ipv4/ipconfig.c | 6 ++
9 files changed, 126 insertions(+), 49 deletions(-)

--
2.36.1.255.ge46751e96f-goog