linux-stable.git/drivers/base/core.c, branch v5.15.78

PM: runtime: Redefine pm_runtime_release_supplier()

2022-07-12T14:35:09+00:00

commit 07358194badf73e267289b40b761f5dc56928eab upstream.

Instead of passing an extra bool argument to pm_runtime_release_supplier(),
make its callers take care of triggering a runtime-suspend of the
supplier device as needed.

No expected functional impact.

Suggested-by: Greg Kroah-Hartman 
Signed-off-by: Rafael J. Wysocki 
Reviewed-by: Greg Kroah-Hartman 
Cc: 5.1+  # 5.1+
Signed-off-by: Greg Kroah-Hartman

PM: runtime: Add safety net to supplier device release

2022-01-27T10:04:44+00:00

[ Upstream commit d1579e61192e0e686faa4208500ef4c3b529b16c ]

Because refcount_dec_not_one() returns true if the target refcount
becomes saturated, it is generally unsafe to use its return value as
a loop termination condition, but that is what happens when a device
link's supplier device is released during runtime PM suspend
operations and on device link removal.

To address this, introduce pm_runtime_release_supplier() to be used
in the above cases which will check the supplier device's runtime
PM usage counter in addition to the refcount_dec_not_one() return
value, so the loop can be terminated in case the rpm_active refcount
value becomes invalid, and update the code in question to use it as
appropriate.

This change is not expected to have any visible functional impact.

Reported-by: Peter Zijlstra 
Signed-off-by: Rafael J. Wysocki 
Acked-by: Greg Kroah-Hartman 
Acked-by: Peter Zijlstra (Intel) 
Signed-off-by: Sasha Levin

driver core: Fix possible memory leak in device_link_add()

2021-11-18T18:16:50+00:00

[ Upstream commit df0a18149474c7e6b21f6367fbc6bc8d0f192444 ]

I got memory leak as follows:

unreferenced object 0xffff88801f0b2200 (size 64):
  comm "i2c-lis2hh12-21", pid 5455, jiffies 4294944606 (age 15.224s)
  hex dump (first 32 bytes):
    72 65 67 75 6c 61 74 6f 72 3a 72 65 67 75 6c 61  regulator:regula
    74 6f 72 2e 30 2d 2d 69 32 63 3a 31 2d 30 30 31  tor.0--i2c:1-001
  backtrace:
    [<00000000bf5b0c3b>] __kmalloc_track_caller+0x19f/0x3a0
    [<0000000050da42d9>] kvasprintf+0xb5/0x150
    [<000000004bbbed13>] kvasprintf_const+0x60/0x190
    [<00000000cdac7480>] kobject_set_name_vargs+0x56/0x150
    [<00000000bf83f8e8>] dev_set_name+0xc0/0x100
    [<00000000cc1cf7e3>] device_link_add+0x6b4/0x17c0
    [<000000009db9faed>] _regulator_get+0x297/0x680
    [<00000000845e7f2b>] _devm_regulator_get+0x5b/0xe0
    [<000000003958ee25>] st_sensors_power_enable+0x71/0x1b0 [st_sensors]
    [<000000005f450f52>] st_accel_i2c_probe+0xd9/0x150 [st_accel_i2c]
    [<00000000b5f2ab33>] i2c_device_probe+0x4d8/0xbe0
    [<0000000070fb977b>] really_probe+0x299/0xc30
    [<0000000088e226ce>] __driver_probe_device+0x357/0x500
    [<00000000c21dda32>] driver_probe_device+0x4e/0x140
    [<000000004e650441>] __device_attach_driver+0x257/0x340
    [<00000000cf1891b8>] bus_for_each_drv+0x166/0x1e0

When device_register() returns an error, the name allocated in dev_set_name()
will be leaked, the put_device() should be used instead of kfree() to give up
the device reference, then the name will be freed in kobject_cleanup() and the
references of consumer and supplier will be decreased in device_link_release_fn().

Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs")
Reported-by: Hulk Robot 
Reviewed-by: Saravana Kannan 
Reviewed-by: Rafael J. Wysocki 
Signed-off-by: Yang Yingliang 
Link: https://lore.kernel.org/r/20210930085714.2057460-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

driver core: Reject pointless SYNC_STATE_ONLY device links

2021-10-05T15:45:54+00:00

SYNC_STATE_ONLY device links intentionally allow cycles because cyclic
sync_state() dependencies are valid and necessary.

However a SYNC_STATE_ONLY device link where the consumer and the supplier
are the same device is pointless because the device link would be deleted
as soon as the device probes (because it's also the consumer) and won't
affect when the sync_state() callback is called. It's a waste of CPU cycles
and memory to create this device link. So reject any attempts to create
such a device link.

Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag")
Cc: stable 
Reported-by: Ulf Hansson 
Reviewed-by: Rafael J. Wysocki 
Reviewed-by: Ulf Hansson 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210929190549.860541-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: Add debug logs when fwnode links are added/deleted

2021-09-28T07:48:48+00:00

This will help with debugging fw_devlink issues.

Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210915172808.620546-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: Create __fwnode_link_del() helper function

2021-09-28T07:48:48+00:00

The same code is repeated in multiple locations. Create a helper
function for it.

Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210915172808.620546-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: Set deferred probe reason when deferred by driver core

2021-09-28T07:48:48+00:00

When the driver core defers the probe of a device, set the deferred
probe reason so that it's easier to debug. The deferred probe reason is
available in debugfs under devices_deferred.

Reviewed-by: Geert Uytterhoeven 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210915172808.620546-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: fw_devlink: Add support for FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD

2021-09-23T17:26:54+00:00

If a parent device is also a supplier to a child device, fw_devlink=on by
design delays the probe() of the child device until the probe() of the
parent finishes successfully.

However, some drivers of such parent devices (where parent is also a
supplier) expect the child device to finish probing successfully as soon as
they are added using device_add() and before the probe() of the parent
device has completed successfully. One example of such a case is discussed
in the link mentioned below.

Add a flag to make fw_devlink=on not enforce these supplier-consumer
relationships, so these drivers can continue working.

Link: https://lore.kernel.org/netdev/CAGETcx_uj0V4DChME-gy5HGKTYnxLBX=TH2rag29f_p=UcG+Tg@mail.gmail.com/
Fixes: ea718c699055 ("Revert "Revert "driver core: Set fw_devlink=on by default""")
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210915170940.617415-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: fw_devlink: Improve handling of cyclic dependencies

2021-09-21T16:21:48+00:00

When we have a dependency of the form:

Device-A -> Device-C
	Device-B

Device-C -> Device-B

Where,
* Indentation denotes "child of" parent in previous line.
* X -> Y denotes X is consumer of Y based on firmware (Eg: DT).

We have cyclic dependency: device-A -> device-C -> device-B -> device-A

fw_devlink current treats device-C -> device-B dependency as an invalid
dependency and doesn't enforce it but leaves the rest of the
dependencies as is.

While the current behavior is necessary, it is not sufficient if the
false dependency in this example is actually device-A -> device-C. When
this is the case, device-C will correctly probe defer waiting for
device-B to be added, but device-A will be incorrectly probe deferred by
fw_devlink waiting on device-C to probe successfully. Due to this, none
of the devices in the cycle will end up probing.

To fix this, we need to go relax all the dependencies in the cycle like
we already do in the other instances where fw_devlink detects cycles.
A real world example of this was reported[1] and analyzed[2].

[1] - https://lore.kernel.org/lkml/0a2c4106-7f48-2bb5-048e-8c001a7c3fda@samsung.com/
[2] - https://lore.kernel.org/lkml/CAGETcx8peaew90SWiux=TyvuGgvTQOmO4BFALz7aj0Za5QdNFQ@mail.gmail.com/

Fixes: f9aa460672c9 ("driver core: Refactor fw_devlink feature")
Cc: stable 
Reported-by: Marek Szyprowski 
Tested-by: Marek Szyprowski 
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210915170940.617415-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

Merge branch 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb

2021-09-03T17:34:44+00:00

Pull swiotlb updates from Konrad Rzeszutek Wilk:
 "A new feature called restricted DMA pools. It allows SWIOTLB to
  utilize per-device (or per-platform) allocated memory pools instead of
  using the global one.

  The first big user of this is ARM Confidential Computing where the
  memory for DMA operations can be set per platform"

* 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: (23 commits)
  swiotlb: use depends on for DMA_RESTRICTED_POOL
  of: restricted dma: Don't fail device probe on rmem init failure
  of: Move of_dma_set_restricted_buffer() into device.c
  powerpc/svm: Don't issue ultracalls if !mem_encrypt_active()
  s390/pv: fix the forcing of the swiotlb
  swiotlb: Free tbl memory in swiotlb_exit()
  swiotlb: Emit diagnostic in swiotlb_exit()
  swiotlb: Convert io_default_tlb_mem to static allocation
  of: Return success from of_dma_set_restricted_buffer() when !OF_ADDRESS
  swiotlb: add overflow checks to swiotlb_bounce
  swiotlb: fix implicit debugfs declarations
  of: Add plumbing for restricted DMA pool
  dt-bindings: of: Add restricted DMA pool
  swiotlb: Add restricted DMA pool initialization
  swiotlb: Add restricted DMA alloc/free support
  swiotlb: Refactor swiotlb_tbl_unmap_single
  swiotlb: Move alloc_size to swiotlb_find_slots
  swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing
  swiotlb: Update is_swiotlb_active to add a struct device argument
  swiotlb: Update is_swiotlb_buffer to add a struct device argument
  ...