linux-toradex.git/drivers/base/dd.c, branch v5.17-rc1

driver core: Make bus notifiers in right order in really_probe()

2022-01-06T14:47:41+00:00

If a driver cannot be bound to a device, the correct bus notifier order
should be:

 - BUS_NOTIFY_BIND_DRIVER: driver is about to be bound
 - BUS_NOTIFY_DRIVER_NOT_BOUND: driver failed to be bound

or no notifier if the failure happens before the actual binding.

The really_probe() notifies a BUS_NOTIFY_DRIVER_NOT_BOUND event without
a BUS_NOTIFY_BIND_DRIVER if .dma_configure() returns failure. This
change makes the notifiers in order.

Signed-off-by: Lu Baolu 
Link: https://lore.kernel.org/r/20211231033901.2168664-3-baolu.lu@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

driver core: Move driver_sysfs_remove() after driver_sysfs_add()

2022-01-06T14:47:41+00:00

The driver_sysfs_remove() should be called after driver_sysfs_add() in
really_probe(). The out-of-order driver_sysfs_remove() tries to remove
some nonexistent nodes under the device and driver sysfs nodes. This is
allowed, hence this change doesn't fix any problem, just a cleanup.

Signed-off-by: Lu Baolu 
Link: https://lore.kernel.org/r/20211231033901.2168664-2-baolu.lu@linux.intel.com
Signed-off-by: Greg Kroah-Hartman

Merge 5.14-rc5 into driver-core-next

2021-08-09T07:03:47+00:00

We need the driver core fixes in here as well.

Signed-off-by: Greg Kroah-Hartman

drivers core: Fix oops when driver probe fails

2021-07-27T12:44:43+00:00

dma_range_map is freed to early, which might cause an oops when
a driver probe fails.
 Call trace:
  is_free_buddy_page+0xe4/0x1d4
  __free_pages+0x2c/0x88
  dma_free_contiguous+0x64/0x80
  dma_direct_free+0x38/0xb4
  dma_free_attrs+0x88/0xa0
  dmam_release+0x28/0x34
  release_nodes+0x78/0x8c
  devres_release_all+0xa8/0x110
  really_probe+0x118/0x2d0
  __driver_probe_device+0xc8/0xe0
  driver_probe_device+0x54/0xec
  __driver_attach+0xe0/0xf0
  bus_for_each_dev+0x7c/0xc8
  driver_attach+0x30/0x3c
  bus_add_driver+0x17c/0x1c4
  driver_register+0xc0/0xf8
  __platform_driver_register+0x34/0x40
  ...

This issue is introduced by commit d0243bbd5dd3 ("drivers core:
Free dma_range_map when driver probe failed"). It frees
dma_range_map before the call to devres_release_all, which is too
early. The solution is to free dma_range_map only after
devres_release_all.

Fixes: d0243bbd5dd3 ("drivers core: Free dma_range_map when driver probe failed")
Cc: stable 
Signed-off-by: Filip Schauer 
Link: https://lore.kernel.org/r/20210727112311.GA7645@DESKTOP-E8BN1B0.localdomain
Signed-off-by: Greg Kroah-Hartman

driver core: Fix error return code in really_probe()

2021-07-21T14:16:23+00:00

In the case of error handling, the error code returned by the subfunction
should be propagated instead of 0.

Fixes: 1901fb2604fb ("Driver core: fix "driver" symlink timing")
Fixes: 23b6904442d0 ("driver core: add dev_groups to all drivers")
Fixes: 8fd456ec0cf0 ("driver core: Add state_synced sysfs file for devices that support it")
Reported-by: Hulk Robot 
Signed-off-by: Zhen Lei 
Link: https://lore.kernel.org/r/20210707074301.2722-1-thunder.leizhen@huawei.com
Signed-off-by: Greg Kroah-Hartman

driver core: Export device_driver_attach()

2021-06-21T21:29:24+00:00

This is intended as a replacement API for device_bind_driver(). It has at
least the following benefits:

- Internal locking. Few of the users of device_bind_driver() follow the
  locking rules

- Calls device driver probe() internally. Notably this means that devm
  support for probe works correctly as probe() error will call
  devres_release_all()

- struct device_driver -> dev_groups is supported

- Simplified calling convention, no need to manually call probe().

The general usage is for situations that already know what driver to bind
and need to ensure the bind is synchronized with other logic. Call
device_driver_attach() after device_add().

If probe() returns a failure then this will be preserved up through to the
error return of device_driver_attach().

Signed-off-by: Jason Gunthorpe 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Cornelia Huck 
Reviewed-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20210617142218.1877096-6-hch@lst.de
Signed-off-by: Alex Williamson

driver core: Don't return EPROBE_DEFER to userspace during sysfs bind

2021-06-21T21:29:24+00:00

EPROBE_DEFER is an internal kernel error code and it should not be leaked
to userspace via the bind_store() sysfs. Userspace doesn't have this
constant and cannot understand it.

Further, it doesn't really make sense to have userspace trigger a deferred
probe via bind_store(), which could eventually succeed, while
simultaneously returning an error back.

Resolve this by splitting driver_probe_device so that the version used
by the sysfs binding that turns EPROBE_DEFER into -EAGAIN, while the one
used for internally binding keeps the error code, and calls
driver_deferred_probe_add where needed.  This also allows to nicely split
out the defer_all_probes / probe_count checks so that they actually allow
for full device_{block,unblock}_probing protection while not bothering
the sysfs bind case.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Cornelia Huck 
Reviewed-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/r/20210617142218.1877096-5-hch@lst.de
Signed-off-by: Alex Williamson

driver core: Flow the return code from ->probe() through to sysfs bind

2021-06-21T21:29:24+00:00

Currently really_probe() returns 1 on success and 0 if the probe() call
fails. This return code arrangement is designed to be useful for
__device_attach_driver() which is walking the device list and trying every
driver. 0 means to keep trying.

However, it is not useful for the other places that call through to
really_probe() that do actually want to see the probe() return code.

For instance bind_store() would be better to return the actual error code
from the driver's probe method, not discarding it and returning -ENODEV.

Reorganize things so that really_probe() returns the error code from
->probe as a (inverted) positive number, and 0 for successful attach.

With this, __device_attach_driver can ignore the (positive) probe errors,
return 1 to exit the loop for a successful binding and pass on the
other negative errors, while device_driver_attach simplify inverts the
positive errors and returns all errors to the sysfs code.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Cornelia Huck 
Link: https://lore.kernel.org/r/20210617142218.1877096-4-hch@lst.de
Signed-off-by: Alex Williamson

driver core: Better distinguish probe errors in really_probe

2021-06-21T21:29:24+00:00

really_probe tries to special case errors from ->probe, but due to all
other initialization added to the function over time now a lot of
internal errors hit that code path as well.  Untangle that by adding
a new probe_err local variable and apply the special casing only to
that.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Cornelia Huck 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Kirti Wankhede 
Link: https://lore.kernel.org/r/20210617142218.1877096-3-hch@lst.de
Signed-off-by: Alex Williamson

driver core: Pull required checks into driver_probe_device()

2021-06-21T21:29:24+00:00

Checking if the dev is dead or if the dev is already bound is a required
precondition to invoking driver_probe_device(). All the call chains
leading here duplicate these checks.

Add it directly to driver_probe_device() so the precondition is clear and
remove the checks from device_driver_attach() and
__driver_attach_async_helper().

The other call chain going through __device_attach_driver() does have
these same checks but they are inlined into logic higher up the call stack
and can't be removed.

The sysfs uAPI call chain starting at bind_store() is a bit confused
because it reads dev->driver unlocked and returns -ENODEV if it is !NULL,
otherwise it reads it again under lock and returns 0 if it is !NULL. Fix
this to always return -EBUSY and always read dev->driver under its lock.

Done in preparation for the next patches which will add additional
callers to driver_probe_device() and will need these checks as well.

Signed-off-by: Jason Gunthorpe 
[hch: drop the extra checks in device_driver_attach and bind_store]
Signed-off-by: Christoph Hellwig 
Reviewed-by: Greg Kroah-Hartman 
Reviewed-by: Cornelia Huck 
Link: https://lore.kernel.org/r/20210617142218.1877096-2-hch@lst.de
Signed-off-by: Alex Williamson