Commit Graph

191 Commits

Author SHA1 Message Date
Saravana Kannan eed6e41813 driver core: Fix locking bug in deferred_probe_timeout_work_func()
list_for_each_entry_safe() is only useful if we are deleting nodes in a
linked list within the loop. It doesn't protect against other threads
adding/deleting nodes to the list in parallel. We need to grab
deferred_probe_mutex when traversing the deferred_probe_pending_list.

Cc: stable@vger.kernel.org
Fixes: 25b4e70dcc ("driver core: allow stopping deferred probe after init")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210402040342.2944858-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-05 09:14:18 +02:00
Ahmad Fatoum f0acf637d6 driver core: clear deferred probe reason on probe retry
When retrying a deferred probe, any old defer reason string should be
discarded. Otherwise, if the probe is deferred again at a different spot,
but without setting a message, the now incorrect probe reason will remain.

This was observed with the i.MX I2C driver, which ultimately failed
to probe due to lack of the GPIO driver. The probe defer for GPIO
doesn't record a message, but a previous probe defer to clock_get did.
This had the effect that /sys/kernel/debug/devices_deferred listed
a misleading probe deferral reason.

Cc: stable <stable@vger.kernel.org>
Fixes: d090b70ede ("driver core: add deferring probe reason to devices_deferred property")
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.kernel.org/r/20210319110459.19966-1-a.fatoum@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-23 15:13:43 +01:00
Greg Kroah-Hartman 895bee2708 Revert "driver core: Reorder devices on successful probe"
This reverts commit 5b6164d346.

Stephan reports problems with this commit, so revert it for now.

Fixes: 5b6164d346 ("driver core: Reorder devices on successful probe")
Link: https://lore.kernel.org/r/X/ycQpu7NIGI969v@gerhold.net
Reported-by: Stephan Gerhold <stephan@gerhold.net>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Rafael. J. Wysocki <rafael@kernel.org>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12 19:02:29 +01:00
Meng Li d0243bbd5d drivers core: Free dma_range_map when driver probe failed
There will be memory leak if driver probe failed. Trace as below:
  backtrace:
    [<000000002415258f>] kmemleak_alloc+0x3c/0x50
    [<00000000f447ebe4>] __kmalloc+0x208/0x530
    [<0000000048bc7b3a>] of_dma_get_range+0xe4/0x1b0
    [<0000000041e39065>] of_dma_configure_id+0x58/0x27c
    [<000000006356866a>] platform_dma_configure+0x2c/0x40
    ......
    [<000000000afcf9b5>] ret_from_fork+0x10/0x3c

This issue is introduced by commit e0d072782c73("dma-mapping:
introduce DMA range map, supplanting dma_pfn_offset "). It doesn't
free dma_range_map when driver probe failed and cause above
memory leak. So, add code to free it in error path.

Fixes: e0d072782c ("dma-mapping: introduce DMA range map, supplanting dma_pfn_offset ")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Link: https://lore.kernel.org/r/20210105070927.14968-1-Meng.Li@windriver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-08 16:36:19 +01:00
Julian Wiedmann 2c3dc6432f driver core: make driver_probe_device() static
It's only used inside drivers/base/dd.c

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Link: https://lore.kernel.org/r/20201123111938.18968-1-jwi@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:30:44 +01:00
Thierry Reding 5b6164d346 driver core: Reorder devices on successful probe
Device drivers usually depend on the fact that the devices that they
control are suspended in the same order that they were probed in. In
most cases this is already guaranteed via deferred probe.

However, there's one case where this can still break: if a device is
instantiated before a dependency (for example if it appears before the
dependency in device tree) but gets probed only after the dependency is
probed. Instantiation order would cause the dependency to get probed
later, in which case probe of the original device would be deferred and
the suspend/resume queue would get reordered properly. However, if the
dependency is provided by a built-in driver and the device depending on
that driver is controlled by a loadable module, which may only get
loaded after the root filesystem has become available, we can be faced
with a situation where the probe order ends up being different from the
suspend/resume order.

One example where this happens is on Tegra186, where the ACONNECT is
listed very early in device tree (sorted by unit-address) and depends on
BPMP (listed very late because it has no unit-address) for power domains
and clocks/resets. If the ACONNECT driver is built-in, there is no
problem because it will be probed before BPMP, causing a probe deferral
and that in turn reorders the suspend/resume queue. However, if built as
a module, it will end up being probed after BPMP, and therefore not
result in a probe deferral, and therefore the suspend/resume queue will
stay in the instantiation order. This in turn causes problems because
ACONNECT will be resumed before BPMP, which will result in a hang
because the ACONNECT's power domain cannot be powered on as long as the
BPMP is still suspended.

Fix this by always reordering devices on successful probe. This ensures
that the suspend/resume queue is always in probe order and hence meets
the natural expectations of drivers vs. their dependencies.

Reported-by: Jonathan Hunter <jonathanh@nvidia.com>
Acked-by: Rafael. J. Wysocki <rafael@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20201203175756.1405564-1-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:29:01 +01:00
Saravana Kannan c84b90909e Revert "driver core: fw_devlink: Add support for batching fwnode parsing"
This reverts commit 716a7a2596.

The fw_devlink_pause/resume() APIs added by the commit being reverted
were a first cut attempt at optimizing boot time. But these APIs don't
fully solve the problem and are very fragile (can only be used for the
top level devices being added). This series replaces them with a much
better optimization that works for all device additions and also has the
benefit of reducing the complexity of the firmware (DT, EFI) specific
code and abstracting out common code to driver core.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-7-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:10:20 +01:00
Saravana Kannan 999032ece3 Revert "driver core: Remove check in driver_deferred_probe_force_trigger()"
This reverts commit fefcfc9687.

The reverted commit is fixing commit 716a7a2596 ("driver core:
fw_devlink: Add support for batching fwnode parsing"). Since the
original commit will be reverted, the fix can be reverted too.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-5-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:10:20 +01:00
Saravana Kannan 96d8a9168e Revert "driver core: Don't do deferred probe in parallel with kernel_init thread"
This reverts commit cec72f3efc.

Commit cec72f3efc ("driver core: Don't do deferred probe in parallel
with kernel_init thread") was fixing a commit 716a7a2596 ("driver
core: fw_devlink: Add support for batching fwnode parsing"). Since the
commit being fixed itself is going to be reverted, the fix can also be
reverted.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201121020232.908850-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-09 19:10:20 +01:00
Rafael J. Wysocki 9226c504e3 PM: runtime: Resume the device earlier in __device_release_driver()
Since the device is resumed from runtime-suspend in
__device_release_driver() anyway, it is better to do that before
looking for busy managed device links from it to consumers, because
if there are any, device_links_unbind_consumers() will be called
and it will cause the consumer devices' drivers to unbind, so the
consumer devices will be runtime-resumed.  In turn, resuming each
consumer device will cause the supplier to be resumed and when the
runtime PM references from the given consumer to it are dropped, it
may be suspended.  Then, the runtime-resume of the next consumer
will cause the supplier to resume again and so on.

Update the code accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fixes: 9ed9895370 ("driver core: Functional dependencies tracking support")
Cc: All applicable <stable@vger.kernel.org> # All applicable
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-02 18:14:07 +01:00
Rafael J. Wysocki d6e3666859 PM: runtime: Drop pm_runtime_clean_up_links()
After commit d12544fb2a ("PM: runtime: Remove link state checks in
rpm_get/put_supplier()") nothing prevents the consumer device's
runtime PM from acquiring additional references to the supplier
device after pm_runtime_clean_up_links() has run (or even while it
is running), so calling this function from __device_release_driver()
may be pointless (or even harmful).

Moreover, it ignores stateless device links, so the runtime PM
handling of managed and stateless device links is inconsistent
because of it, so better get rid of it entirely.

Fixes: d12544fb2a ("PM: runtime: Remove link state checks in rpm_get/put_supplier()")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-02 18:14:07 +01:00
Linus Torvalds 5a32c3413d dma-mapping updates for 5.10
- rework the non-coherent DMA allocator
  - move private definitions out of <linux/dma-mapping.h>
  - lower CMA_ALIGNMENT (Paul Cercueil)
  - remove the omap1 dma address translation in favor of the common
    code
  - make dma-direct aware of multiple dma offset ranges (Jim Quinlan)
  - support per-node DMA CMA areas (Barry Song)
  - increase the default seg boundary limit (Nicolin Chen)
  - misc fixes (Robin Murphy, Thomas Tai, Xu Wang)
  - various cleanups
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Merge tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - rework the non-coherent DMA allocator

 - move private definitions out of <linux/dma-mapping.h>

 - lower CMA_ALIGNMENT (Paul Cercueil)

 - remove the omap1 dma address translation in favor of the common code

 - make dma-direct aware of multiple dma offset ranges (Jim Quinlan)

 - support per-node DMA CMA areas (Barry Song)

 - increase the default seg boundary limit (Nicolin Chen)

 - misc fixes (Robin Murphy, Thomas Tai, Xu Wang)

 - various cleanups

* tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping: (63 commits)
  ARM/ixp4xx: add a missing include of dma-map-ops.h
  dma-direct: simplify the DMA_ATTR_NO_KERNEL_MAPPING handling
  dma-direct: factor out a dma_direct_alloc_from_pool helper
  dma-direct check for highmem pages in dma_direct_alloc_pages
  dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h>
  dma-mapping: move large parts of <linux/dma-direct.h> to kernel/dma
  dma-mapping: move dma-debug.h to kernel/dma/
  dma-mapping: remove <asm/dma-contiguous.h>
  dma-mapping: merge <linux/dma-contiguous.h> into <linux/dma-map-ops.h>
  dma-contiguous: remove dma_contiguous_set_default
  dma-contiguous: remove dev_set_cma_area
  dma-contiguous: remove dma_declare_contiguous
  dma-mapping: split <linux/dma-mapping.h>
  cma: decrease CMA_ALIGNMENT lower limit to 2
  firewire-ohci: use dma_alloc_pages
  dma-iommu: implement ->alloc_noncoherent
  dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods
  dma-mapping: add a new dma_alloc_pages API
  dma-mapping: remove dma_cache_sync
  53c700: convert to dma_alloc_noncoherent
  ...
2020-10-15 14:43:29 -07:00
Christoph Hellwig 0a0f0d8be7 dma-mapping: split <linux/dma-mapping.h>
Split out all the bits that are purely for dma_map_ops implementations
and related code into a new <linux/dma-map-ops.h> header so that they
don't get pulled into all the drivers.  That also means the architecture
specific <asm/dma-mapping.h> is not pulled in by <linux/dma-mapping.h>
any more, which leads to a missing includes that were pulled in by the
x86 or arm versions in a few not overly portable drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-10-06 07:07:03 +02:00
Joe Perches 948b3edba8 drivers core: Miscellaneous changes for sysfs_emit
Change additional instances that could use sysfs_emit and sysfs_emit_at
that the coccinelle script could not convert.

o macros creating show functions with ## concatenation
o unbound sprintf uses with buf+len for start of output to sysfs_emit_at
o returns with ?: tests and sprintf to sysfs_emit
o sysfs output with struct class * not struct device * arguments

Miscellanea:

o remove unnecessary initializations around these changes
o consistently use int len for return length of show functions
o use octal permissions and not S_<FOO>
o rename a few show function names so DEVICE_ATTR_<FOO> can be used
o use DEVICE_ATTR_ADMIN_RO where appropriate
o consistently use const char *output for strings
o checkpatch/style neatening

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/8bc24444fe2049a9b2de6127389b57edfdfe324d.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-02 13:12:07 +02:00
Joe Perches aa838896d8 drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions
Convert the various sprintf fmaily calls in sysfs device show functions
to sysfs_emit and sysfs_emit_at for PAGE_SIZE buffer safety.

Done with:

$ spatch -sp-file sysfs_emit_dev.cocci --in-place --max-width=80 .

And cocci script:

$ cat sysfs_emit_dev.cocci
@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	sprintf(buf,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	snprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	scnprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	return
-	strcpy(buf, chr);
+	sysfs_emit(buf, chr);
	...>
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	sprintf(buf,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	snprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
	len =
-	scnprintf(buf, PAGE_SIZE,
+	sysfs_emit(buf,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
identifier len;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	<...
-	len += scnprintf(buf + len, PAGE_SIZE - len,
+	len += sysfs_emit_at(buf, len,
	...);
	...>
	return len;
}

@@
identifier d_show;
identifier dev, attr, buf;
expression chr;
@@

ssize_t d_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	...
-	strcpy(buf, chr);
-	return strlen(buf);
+	return sysfs_emit(buf, chr);
}

Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/3d033c33056d88bbe34d4ddb62afd05ee166ab9a.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-02 13:09:10 +02:00
Zenghui Yu e3aa745ff9 driver core: Use the ktime_us_delta() helper
Use the ktime_us_delta() helper to measure the driver probe time. Given the
helpers already returns an s64 value, let's drop the unnecessary casting to
s64 as well. There is no functional change.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Link: https://lore.kernel.org/r/20200803033343.1178-1-yuzenghui@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-08 13:32:06 +02:00
Andrzej Hajda d090b70ede driver core: add deferring probe reason to devices_deferred property
/sys/kernel/debug/devices_deferred property contains list of deferred devices.
This list does not contain reason why the driver deferred probe, the patch
improves it.
The natural place to set the reason is dev_err_probe function introduced
recently, ie. if dev_err_probe will be called with -EPROBE_DEFER instead of
printk the message will be attached to a deferred device and printed when user
reads devices_deferred property.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20200713144324.23654-3-a.hajda@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-30 09:03:43 +02:00
Lukas Wunner 654888327e driver core: Avoid binding drivers to dead devices
Commit 3451a495ef ("driver core: Establish order of operations for
device_add and device_del via bitflag") sought to prevent asynchronous
driver binding to a device which is being removed.  It added a
per-device "dead" flag which is checked in the following code paths:

* asynchronous binding in __driver_attach_async_helper()
*  synchronous binding in device_driver_attach()
* asynchronous binding in __device_attach_async_helper()

It did *not* check the flag upon:

*  synchronous binding in __device_attach()

However __device_attach() may also be called asynchronously from:

deferred_probe_work_func()
  bus_probe_device()
    device_initial_probe()
      __device_attach()

So if the commit's intention was to check the "dead" flag in all
asynchronous code paths, then a check is also necessary in
__device_attach().  Add the missing check.

Fixes: 3451a495ef ("driver core: Establish order of operations for device_add and device_del via bitflag")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v5.1+
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Link: https://lore.kernel.org/r/de88a23a6fe0ef70f7cfd13c8aea9ab51b4edab6.1594214103.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-30 08:48:34 +02:00
Tetsuo Handa b292b50b0e driver core: Fix probe_count imbalance in really_probe()
syzbot is reporting hung task in wait_for_device_probe() [1]. At least,
we always need to decrement probe_count if we incremented probe_count in
really_probe().

However, since I can't find "Resources present before probing" message in
the console log, both "this message simply flowed off" and "syzbot is not
hitting this path" will be possible. Therefore, while we are at it, let's
also prepare for concurrent wait_for_device_probe() calls by replacing
wake_up() with wake_up_all().

[1] https://syzkaller.appspot.com/bug?id=25c833f1983c9c1d512f4ff860dd0d7f5a2e2c0f

Reported-by: syzbot <syzbot+805f5f6ae37411f15b64@syzkaller.appspotmail.com>
Fixes: 7c35e699c8 ("driver core: Print device when resources present in really_probe()")
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20200713021254.3444-1-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-23 15:21:28 +02:00
Greg Kroah-Hartman 6bdb486c5a Merge 5.8-rc6 into driver-core-next
We need the driver core fixes in here too.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-20 09:31:35 +02:00
Saravana Kannan 8fd456ec0c driver core: Add state_synced sysfs file for devices that support it
This can be used to check if a device supports sync_state() callbacks
and therefore keeps resources left on by the bootloader enabled till all
its consumers have probed.

This can also be used to check if sync_state() has been called for a
device or whether it is still trying to keep resources enabled because
they were left enabled by the bootloader and all its consumers haven't
probed yet.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200521191800.136035-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10 15:24:56 +02:00
Saravana Kannan cec72f3efc driver core: Don't do deferred probe in parallel with kernel_init thread
The current deferred probe implementation can mess up suspend/resume
ordering if deferred probe thread is kicked off in parallel with the
main initcall thread (kernel_init thread) [1].

For example:

Say device-B is a consumer of device-A.

Initcall thread					Deferred probe thread
===============					=====================
1. device-A is added.
2. device-B is added.
3. dpm_list is now [device-A, device-B].
4. driver-A defers probe of device-A.
						5. device-A is moved to
						   end of dpm_list
						6. dpm_list is now
						   [device-B, device-A]
7. driver-B is registereed and probes device-B.
8. dpm_list stays as [device-B, device-A].

The reverse order of dpm_list is used for suspend. So in this case
device-A would incorrectly get suspended before device-B.

Commit 716a7a2596 ("driver core: fw_devlink: Add support for batching
fwnode parsing") kicked off the deferred probe thread early during boot
to run in parallel with the initcall thread and caused suspend/resume
regressions.  This patch removes the parallel run of the deferred probe
thread to avoid the suspend/resume regressions.

[1] - https://lore.kernel.org/lkml/CAGETcx8W96KAw-d_siTX4qHB_-7ddk0miYRDQeHE6E0_8qx-6Q@mail.gmail.com/

Fixes: 716a7a2596 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10 15:20:38 +02:00
Lukas Wunner fe940d7362 driver core: Drop mention of obsolete bus rwsem from kernel-doc
15 years ago, commit 6eded061b1 ("Fix up bus code and remove use of
rwsem") removed the bus rwsem, but left over a reference to it in a
kernel-doc comment.  Drop it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/b1af31b0e351bcbc056fe1ec44500737a7998d43.1594210157.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10 15:13:43 +02:00
Saravana Kannan fefcfc9687 driver core: Remove check in driver_deferred_probe_force_trigger()
The whole point behind adding driver_deferred_probe_force_trigger() in
commit 716a7a2596 ("driver core: fw_devlink: Add support for batching
fwnode parsing") was to skip the check for driver_deferred_probe_enable.
Otherwise, it's identical to driver_deferred_probe_trigger().

Delete the check in driver_deferred_probe_force_trigger() so that
fw_devlink_pause() and fw_devlink_resume() can kick off deferred probe
as intended. Without doing this forced deferred probe trigger, some
platforms seem to be crashing during boot because they assume probe
order of devices.

Fixes: 716a7a2596 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200517173453.157703-1-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-19 16:48:23 +02:00
Saravana Kannan 716a7a2596 driver core: fw_devlink: Add support for batching fwnode parsing
The amount of time spent parsing fwnodes of devices can become really
high if the devices are added in an non-ideal order. Worst case can be
O(N^2) when N devices are added. But this can be optimized to O(N) by
adding all the devices and then parsing all their fwnodes in one batch.

This commit adds fw_devlink_pause() and fw_devlink_resume() to allow
doing this.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20200515053500.215929-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-15 16:34:52 +02:00
Greg Kroah-Hartman c8be6af9ef Merge v5.7-rc5 into driver-core-next
We want the driver core fixes in here and this resolves a merge issue
with drivers/base/dd.c

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-11 09:00:09 +02:00
Christophe JAILLET eb7fbc9fb1 driver core: Add missing '\n' in log messages
Message logged by 'dev_xxx()' or 'pr_xxx()' should end with a '\n'.

While at it, convert some "printk(KERN_" into equivalent but less verbose
(pr|dev)_xxx functions.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20200411133158.27390-1-christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28 21:05:42 +02:00
John Stultz 35a672363a driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires
In commit c8c43cee29 ("driver core: Fix
driver_deferred_probe_check_state() logic"), we set the default
driver_deferred_probe_timeout value to 30 seconds to allow for
drivers that are missing dependencies to have some time so that
the dependency may be loaded from userland after initcalls_done
is set.

However, Yoshihiro Shimoda reported that on his device that
expects to have unmet dependencies (due to "optional links" in
its devicetree), was failing to mount the NFS root.

In digging further, it seemed the problem was that while the
device properly probes after waiting 30 seconds for any missing
modules to load, the ip_auto_config() had already failed,
resulting in NFS to fail. This was due to ip_auto_config()
calling wait_for_device_probe() which doesn't wait for the
driver_deferred_probe_timeout to fire.

This patch tries to fix the issue by creating a waitqueue
for the driver_deferred_probe_timeout, and calling wait_event()
to make sure driver_deferred_probe_timeout is zero in
wait_for_device_probe() to make sure all the probing is
finished.

The downside to this solution is that kernel functionality that
uses wait_for_device_probe(), will block until the
driver_deferred_probe_timeout fires, regardless of if there is
any missing dependencies.

However, the previous patch reverts the default timeout value to
zero, so this side-effect will only affect users who specify a
driver_deferred_probe_timeout= value as a boot argument, where
the additional delay would be beneficial to allow modules to
load later during boot.

Thanks to Geert for chasing down that ip_auto_config was why NFS
was failing in this case!

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Basil Eljuse <Basil.Eljuse@arm.com>
Cc: Ferry Toth <fntoth@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: linux-pm@vger.kernel.org
Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: c8c43cee29 ("driver core: Fix driver_deferred_probe_check_state() logic")
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200422203245.83244-4-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28 17:57:13 +02:00
John Stultz 4ccc03e28e driver core: Use dev_warn() instead of dev_WARN() for deferred_probe_timeout warnings
In commit c8c43cee29 ("driver core: Fix
driver_deferred_probe_check_state() logic") and following
changes the logic was changes slightly so that if there is no
driver to match whats found in the dtb, we wait the sepcified
seconds for modules to be loaded by userland, and then timeout,
where as previously we'd print "ignoring dependency for device,
assuming no driver" and immediately return -ENODEV after
initcall_done.

However, in the timeout case (which previously existed but was
practicaly un-used without a boot argument), the timeout message
uses dev_WARN(). This means folks are now seeing a big backtrace
in their boot logs if there a entry in their dts that doesn't
have a driver.

To fix this, lets use dev_warn(), instead of dev_WARN() to match
the previous error path.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Basil Eljuse <Basil.Eljuse@arm.com>
Cc: Ferry Toth <fntoth@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: linux-pm@vger.kernel.org
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: c8c43cee29 ("driver core: Fix driver_deferred_probe_check_state() logic")
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200422203245.83244-3-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28 17:57:13 +02:00
John Stultz ce68929f07 driver core: Revert default driver_deferred_probe_timeout value to 0
This patch addresses a regression in 5.7-rc1+

In commit c8c43cee29 ("driver core: Fix
driver_deferred_probe_check_state() logic"), we both cleaned up
the logic and also set the default driver_deferred_probe_timeout
value to 30 seconds to allow for drivers that are missing
dependencies to have some time so that the dependency may be
loaded from userland after initcalls_done is set.

However, Yoshihiro Shimoda reported that on his device that
expects to have unmet dependencies (due to "optional links" in
its devicetree), was failing to mount the NFS root.

In digging further, it seemed the problem was that while the
device properly probes after waiting 30 seconds for any missing
modules to load, the ip_auto_config() had already failed,
resulting in NFS to fail. This was due to ip_auto_config()
calling wait_for_device_probe() which doesn't wait for the
driver_deferred_probe_timeout to fire.

Fixing that issue is possible, but could also introduce 30
second delays in bootups for users who don't have any
missing dependencies, which is not ideal.

So I think the best solution to avoid any regressions is to
revert back to a default timeout value of zero, and allow
systems that need to utilize the timeout in order for userland
to load any modules that supply misisng dependencies in the dts
to specify the timeout length via the exiting documented boot
argument.

Thanks to Geert for chasing down that ip_auto_config was why NFS
was failing in this case!

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Basil Eljuse <Basil.Eljuse@arm.com>
Cc: Ferry Toth <fntoth@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Anders Roxell <anders.roxell@linaro.org>
Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: c8c43cee29 ("driver core: Fix driver_deferred_probe_check_state() logic")
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200422203245.83244-2-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-28 17:56:26 +02:00
Andy Shevchenko a3a87d66d3 driver core: Replace open-coded list_last_entry()
There is a place in the code where open-coded version of list entry accessors
list_last_entry() is used.

Replace that with the standard macro.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200324122023.9649-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24 13:33:26 +01:00
Andy Shevchenko 927f82875c driver core: Read atomic counter once in driver_probe_done()
Between printing the debug message and actual check atomic counter can be
altered. For better debugging experience read atomic counter value only once.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Link: https://lore.kernel.org/r/20200324122023.9649-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-24 13:33:25 +01:00
John Stultz 64c775fb4b driver core: Rename deferred_probe_timeout and make it global
Since other subsystems (like regulator) have similar arbitrary
timeouts for how long they try to resolve driver dependencies,
rename deferred_probe_timeout to driver_deferred_probe_timeout
and set it as global, so it can be shared.

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-6-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 18:11:44 +01:00
John Stultz 0e9f8d09d2 driver core: Remove driver_deferred_probe_check_state_continue()
Now that driver_deferred_probe_check_state() works better, and
we've converted the only user of
driver_deferred_probe_check_state_continue() we can simply
remove it and simplify some of the logic.

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-5-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 18:11:44 +01:00
John Stultz e2cec7d685 driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set
When using modules, its common for the modules not to be loaded
until quite late by userland. With the current code,
driver_deferred_probe_check_state() will stop returning
EPROBE_DEFER after late_initcall, which can cause module
dependency resolution to fail after that.

So allow a longer window of 30 seconds (picked somewhat
arbitrarily, but influenced by the similar regulator core
timeout value) in the case where modules are enabled.

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-3-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 18:11:44 +01:00
John Stultz c8c43cee29 driver core: Fix driver_deferred_probe_check_state() logic
driver_deferred_probe_check_state() has some uninituitive behavior.

* From boot to late_initcall, it returns -EPROBE_DEFER

* From late_initcall to the deferred_probe_timeout (if set)
  it returns -ENODEV

* If the deferred_probe_timeout it set, after it fires, it
  returns -ETIMEDOUT

This is a bit confusing, as its useful to have the function
return -EPROBE_DEFER while the timeout is still running. This
behavior has resulted in the somwhat duplicative
driver_deferred_probe_check_state_continue() function being
added.

Thus this patch tries to improve the logic, so that it behaves
as such:

* If late_initcall has passed, and modules are not enabled
  it returns -ENODEV

* If modules are enabled and deferred_probe_timeout is set,
  it returns -EPROBE_DEFER until the timeout, afterwhich it
  returns -ETIMEDOUT.

* In all other cases, it returns -EPROBE_DEFER

This will make the deferred_probe_timeout value much more
functional, and will allow us to consolidate the
driver_deferred_probe_check_state() and
driver_deferred_probe_check_state_continue() logic in a later
patch.

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-2-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-04 18:11:44 +01:00
Geert Uytterhoeven 7c35e699c8 driver core: Print device when resources present in really_probe()
If a device already has devres items attached before probing, a warning
backtrace is printed.  However, this backtrace does not reveal the
offending device, leaving the user uninformed.  Furthermore, using
WARN_ON() causes systems with panic-on-warn to reboot.

Fix this by replacing the WARN_ON() by a dev_crit() message.
Abort probing the device, to prevent doing more damage to the device's
resources.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20191206132219.28908-1-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14 16:14:48 +01:00
Greg Kroah-Hartman 33cbfe5449 Revert "driver core: Add edit_links() callback for drivers"
This reverts commit 134b23eec9.

Based on a lot of email and in-person discussions, this patch series is
being reworked to address a number of issues that were pointed out that
needed to be taken care of before it should be merged.  It will be
resubmitted with those changes hopefully soon.

Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-27 21:41:06 +02:00
Greg Kroah-Hartman 97e2551de3 dev_groups added to struct driver
Persistent tag for others to pull this branch from
 
 This is the first patch in a longer series that adds the ability for the
 driver core to create and remove a list of attribute groups
 automatically when the device is bound/unbound from a specific driver.
 
 See:
 	https://lore.kernel.org/r/20190731124349.4474-2-gregkh@linuxfoundation.org
 for details on this patch, and examples of how to use it in other
 drivers.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'dev_groups_all_drivers' into driver-core-next

dev_groups added to struct driver

Persistent tag for others to pull this branch from

This is the first patch in a longer series that adds the ability for the
driver core to create and remove a list of attribute groups
automatically when the device is bound/unbound from a specific driver.

See:
	https://lore.kernel.org/r/20190731124349.4474-2-gregkh@linuxfoundation.org
for details on this patch, and examples of how to use it in other
drivers.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-02 12:47:05 +02:00
Dmitry Torokhov 23b6904442 driver core: add dev_groups to all drivers
Add the ability for the driver core to create and remove a list of
attribute groups automatically when the device is bound/unbound from a
specific driver.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Richard Gong <richard.gong@linux.intel.com>
Link: https://lore.kernel.org/r/20190731124349.4474-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-02 12:37:53 +02:00
Saravana Kannan 134b23eec9 driver core: Add edit_links() callback for drivers
The driver core/bus adding supplier-consumer dependencies by default
enables functional dependencies to be tracked correctly even when the
consumer devices haven't had their drivers registered or loaded (if they
are modules).

However, when the bus incorrectly adds dependencies that it shouldn't
have added, the devices might never probe.

For example, if device-C is a consumer of device-S and they have
phandles to each other in DT, the following could happen:

1.  Device-S get added first.
2.  The bus add_links() callback will (incorrectly) try to link it as
    a consumer of device-C.
3.  Since device-C isn't present, device-S will be put in
    "waiting-for-supplier" list.
4.  Device-C gets added next.
5.  All devices in "waiting-for-supplier" list are retried for linking.
6.  Device-S gets linked as consumer to Device-C.
7.  The bus add_links() callback will (correctly) try to link it as
    a consumer of device-S.
8.  This isn't allowed because it would create a cyclic device links.

Neither devices will get probed since the supplier is marked as
dependent on the consumer. And the consumer will never probe because the
consumer can't get resources from the supplier.

Without this patch, things stay in this broken state. However, with this
patch, the execution will continue like this:

9.  Device-C's driver is loaded.
10. Device-C's driver removes Device-S as a consumer of Device-C.
11. Device-C's driver adds Device-C as a consumer of Device-S.
12. Device-S probes.
14. Device-C probes.

kbuild test robot reported missing documentation for device.has_edit_links
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-3-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-01 16:04:13 +02:00
Thierry Reding 62a6bc3a1e driver: core: Allow subsystems to continue deferring probe
Some subsystems, such as pinctrl, allow continuing to defer probe
indefinitely. This is useful for devices that depend on resources
provided by devices that are only probed after the init stage.

One example of this can be seen on Tegra, where the DPAUX hardware
contains pinmuxing controls for pins that it shares with an I2C
controller. The I2C controller is typically used for communication
with a monitor over HDMI (DDC). However, other instances of the I2C
controller are used to access system critical components, such as a
PMIC. The I2C controller driver will therefore usually be a builtin
driver, whereas the DPAUX driver is part of the display driver that
is loaded from a module to avoid bloating the kernel image with all
of the DRM/KMS subsystem.

In this particular case the pins used by this I2C/DDC controller
become accessible very late in the boot process. However, since the
controller is only used in conjunction with display, that's not an
issue.

Unfortunately the driver core currently outputs a warning message
when a device fails to get the pinctrl before the end of the init
stage. That can be confusing for the user because it may sound like
an unwanted error occurred, whereas it's really an expected and
harmless situation.

In order to eliminate this warning, this patch allows callers of the
driver_deferred_probe_check_state() helper to specify that they want
to continue deferring probe, regardless of whether we're past the
init stage or not. All of the callers of that function are updated
for the new signature, but only the pinctrl subsystem passes a true
value in the new persist parameter if appropriate.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190621151725.20414-1-thierry.reding@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 21:28:20 +02:00
John Garry 0b777eee88 driver core: Postpone DMA tear-down until after devres release for probe failure
In commit 376991db4b ("driver core: Postpone DMA tear-down until after
devres release"), we changed the ordering of tearing down the device DMA
ops and releasing all the device's resources; this was because the DMA ops
should be maintained until we release the device's managed DMA memories.

However, we have seen another crash on an arm64 system when a
device driver probe fails:

  hisi_sas_v3_hw 0000:74:02.0: Adding to iommu group 2
  scsi host1: hisi_sas_v3_hw
  BUG: Bad page state in process swapper/0  pfn:313f5
  page:ffff7e0000c4fd40 count:1 mapcount:0
  mapping:0000000000000000 index:0x0
  flags: 0xfffe00000001000(reserved)
  raw: 0fffe00000001000 ffff7e0000c4fd48 ffff7e0000c4fd48
0000000000000000
  raw: 0000000000000000 0000000000000000 00000001ffffffff
0000000000000000
  page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
  bad because of flags: 0x1000(reserved)
  Modules linked in:
  CPU: 49 PID: 1 Comm: swapper/0 Not tainted
5.1.0-rc1-43081-g22d97fd-dirty #1433
  Hardware name: Huawei D06/D06, BIOS Hisilicon D06 UEFI
RC0 - V1.12.01 01/29/2019
  Call trace:
  dump_backtrace+0x0/0x118
  show_stack+0x14/0x1c
  dump_stack+0xa4/0xc8
  bad_page+0xe4/0x13c
  free_pages_check_bad+0x4c/0xc0
  __free_pages_ok+0x30c/0x340
  __free_pages+0x30/0x44
  __dma_direct_free_pages+0x30/0x38
  dma_direct_free+0x24/0x38
  dma_free_attrs+0x9c/0xd8
  dmam_release+0x20/0x28
  release_nodes+0x17c/0x220
  devres_release_all+0x34/0x54
  really_probe+0xc4/0x2c8
  driver_probe_device+0x58/0xfc
  device_driver_attach+0x68/0x70
  __driver_attach+0x94/0xdc
  bus_for_each_dev+0x5c/0xb4
  driver_attach+0x20/0x28
  bus_add_driver+0x14c/0x200
  driver_register+0x6c/0x124
  __pci_register_driver+0x48/0x50
  sas_v3_pci_driver_init+0x20/0x28
  do_one_initcall+0x40/0x25c
  kernel_init_freeable+0x2b8/0x3c0
  kernel_init+0x10/0x100
  ret_from_fork+0x10/0x18
  Disabling lock debugging due to kernel taint
  BUG: Bad page state in process swapper/0  pfn:313f6
  page:ffff7e0000c4fd80 count:1 mapcount:0
mapping:0000000000000000 index:0x0
[   89.322983] flags: 0xfffe00000001000(reserved)
  raw: 0fffe00000001000 ffff7e0000c4fd88 ffff7e0000c4fd88
0000000000000000
  raw: 0000000000000000 0000000000000000 00000001ffffffff
0000000000000000

The crash occurs for the same reason.

In this case, on the really_probe() failure path, we are still clearing
the DMA ops prior to releasing the device's managed memories.

This patch fixes this issue by reordering the DMA ops teardown and the
call to devres_release_all() on the failure path.

Reported-by: Xiang Chen <chenxiang66@hisilicon.com>
Tested-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-25 21:48:37 +02:00
Feng Tang 1ea61b68d0 async: Add cmdline option to specify drivers to be async probed
Asynchronous driver probing can help much on kernel fastboot, and
this option can provide a flexible way to optimize and quickly verify
async driver probe.

Also it will help in below cases:
* Some driver actually covers several families of HWs, some of which
  could use async probing while others don't. So we can't simply
  turn on the PROBE_PREFER_ASYNCHRONOUS flag in driver, but use this
  cmdline option, like igb driver async patch discussed at
  https://www.spinics.net/lists/netdev/msg545986.html

* For SOC (System on Chip) with multiple spi or i2c controllers, most
  of the slave spi/i2c devices will be assigned with fixed controller
  number, while async probing may make those controllers get different
  index for each boot, which prevents those controller drivers to be
  async probed. For platforms not using these spi/i2c slave devices,
  they can use this cmdline option to benefit from the async probing.

Suggested-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-14 10:51:39 +01:00
Geert Uytterhoeven 376991db4b driver core: Postpone DMA tear-down until after devres release
When unbinding the (IOMMU-enabled) R-Car SATA device on Salvator-XS
(R-Car H3 ES2.0), in preparation of rebinding against vfio-platform for
device pass-through for virtualization:

    echo ee300000.sata > /sys/bus/platform/drivers/sata_rcar/unbind

the kernel crashes with:

    Unable to handle kernel paging request at virtual address ffffffbf029ffffc
    Mem abort info:
      ESR = 0x96000006
      Exception class = DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
    Data abort info:
      ISV = 0, ISS = 0x00000006
      CM = 0, WnR = 0
    swapper pgtable: 4k pages, 39-bit VAs, pgdp = 000000007e8c586c
    [ffffffbf029ffffc] pgd=000000073bfc6003, pud=000000073bfc6003, pmd=0000000000000000
    Internal error: Oops: 96000006 [#1] SMP
    Modules linked in:
    CPU: 0 PID: 1098 Comm: bash Not tainted 5.0.0-rc5-salvator-x-00452-g37596f884f4318ef #287
    Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT)
    pstate: 60400005 (nZCv daif +PAN -UAO)
    pc : __free_pages+0x8/0x58
    lr : __dma_direct_free_pages+0x50/0x5c
    sp : ffffff801268baa0
    x29: ffffff801268baa0 x28: 0000000000000000
    x27: ffffffc6f9c60bf0 x26: ffffffc6f9c60bf0
    x25: ffffffc6f9c60810 x24: 0000000000000000
    x23: 00000000fffff000 x22: ffffff8012145000
    x21: 0000000000000800 x20: ffffffbf029fffc8
    x19: 0000000000000000 x18: ffffffc6f86c42c8
    x17: 0000000000000000 x16: 0000000000000070
    x15: 0000000000000003 x14: 0000000000000000
    x13: ffffff801103d7f8 x12: 0000000000000028
    x11: ffffff8011117604 x10: 0000000000009ad8
    x9 : ffffff80110126d0 x8 : ffffffc6f7563000
    x7 : 6b6b6b6b6b6b6b6b x6 : 0000000000000018
    x5 : ffffff8011cf3cc8 x4 : 0000000000004000
    x3 : 0000000000080000 x2 : 0000000000000001
    x1 : 0000000000000000 x0 : ffffffbf029fffc8
    Process bash (pid: 1098, stack limit = 0x00000000c38e3e32)
    Call trace:
     __free_pages+0x8/0x58
     __dma_direct_free_pages+0x50/0x5c
     arch_dma_free+0x1c/0x98
     dma_direct_free+0x14/0x24
     dma_free_attrs+0x9c/0xdc
     dmam_release+0x18/0x20
     release_nodes+0x25c/0x28c
     devres_release_all+0x48/0x4c
     device_release_driver_internal+0x184/0x1f0
     device_release_driver+0x14/0x1c
     unbind_store+0x70/0xb8
     drv_attr_store+0x24/0x34
     sysfs_kf_write+0x4c/0x64
     kernfs_fop_write+0x154/0x1c4
     __vfs_write+0x34/0x164
     vfs_write+0xb4/0x16c
     ksys_write+0x5c/0xbc
     __arm64_sys_write+0x14/0x1c
     el0_svc_common+0x98/0x114
     el0_svc_handler+0x1c/0x24
     el0_svc+0x8/0xc
    Code: d51b4234 17fffffa a9bf7bfd 910003fd (b9403404)
    ---[ end trace 8c564cdd3a1a840f ]---

While I've bisected this to commit e8e683ae9a ("iommu/of: Fix
probe-deferral"), and reverting that commit on post-v5.0-rc4 kernels
does fix the problem, this turned out to be a red herring.

On arm64, arch_teardown_dma_ops() resets dev->dma_ops to NULL.
Hence if a driver has used a managed DMA allocation API, the allocated
DMA memory will be freed using the direct DMA ops, while it may have
been allocated using a custom DMA ops (iommu_dma_ops in this case).

Fix this by reversing the order of the calls to devres_release_all() and
arch_teardown_dma_ops().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-08 12:56:33 +01:00
Rafael J. Wysocki e7dd40105a driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER
Add a new device link flag, DL_FLAG_AUTOPROBE_CONSUMER, to request the
driver core to probe for a consumer driver automatically after binding
a driver to the supplier device on a persistent managed device link.

As unbinding the supplier driver on a managed device link causes the
consumer driver to be detached from its device automatically, this
flag provides a complementary mechanism which is needed to address
some "composite device" use cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-01 10:04:08 +01:00
Alexander Duyck c37e20eaf4 driver core: Attach devices on CPU local to device node
Call the asynchronous probe routines on a CPU local to the device node. By
doing this we should be able to improve our initialization time
significantly as we can avoid having to access the device from a remote
node which may introduce higher latency.

For example, in the case of initializing memory for NVDIMM this can have a
significant impact as initialing 3TB on remote node can take up to 39
seconds while initialing it on a local node only takes 23 seconds. It is
situations like this where we will see the biggest improvement.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 14:20:54 +01:00
Alexander Duyck ef0ff68351 driver core: Probe devices asynchronously instead of the driver
Probe devices asynchronously instead of the driver. This results in us
seeing the same behavior if the device is registered before the driver or
after. This way we can avoid serializing the initialization should the
driver not be loaded until after the devices have already been added.

The motivation behind this is that if we have a set of devices that
take a significant amount of time to load we can greatly reduce the time to
load by processing them in parallel instead of one at a time. In addition,
each device can exist on a different node so placing a single thread on one
CPU to initialize all of the devices for a given driver can result in poor
performance on a system with multiple nodes.

This approach can reduce the time needed to scan SCSI LUNs significantly.
The only way to realize that speedup is by enabling more concurrency which
is what is achieved with this patch.

To achieve this it was necessary to add a new member "async_driver" to the
device_private structure to store the driver pointer while we wait on the
deferred probe call.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 14:20:53 +01:00
Alexander Duyck ed88747c6c device core: Consolidate locking and unlocking of parent and device
Try to consolidate all of the locking and unlocking of both the parent and
device when attaching or removing a driver from a given device.

To do that I first consolidated the lock pattern into two functions
__device_driver_lock and __device_driver_unlock. After doing that I then
created functions specific to attaching and detaching the driver while
acquiring these locks. By doing this I was able to reduce the number of
spots where we touch need_parent_lock from 12 down to 4.

This patch should produce no functional changes, it is meant to be a code
clean-up/consolidation only.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 14:20:53 +01:00
Alexander Duyck 3451a495ef driver core: Establish order of operations for device_add and device_del via bitflag
Add an additional bit flag to the device_private struct named "dead".

This additional flag provides a guarantee that when a device_del is
executed on a given interface an async worker will not attempt to attach
the driver following the earlier device_del call. Previously this
guarantee was not present and could result in the device_del call
attempting to remove a driver from an interface only to have the async
worker attempt to probe the driver later when it finally completes the
asynchronous probe call.

One additional change added was that I pulled the check for dev->driver
out of the __device_attach_driver call and instead placed it in the
__device_attach_async_helper call. This was motivated by the fact that the
only other caller of this, __device_attach, had already taken the
device_lock() and checked for dev->driver. Instead of testing for this
twice in this path it makes more sense to just consolidate the dev->dead
and dev->driver checks together into one set of checks.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-31 14:20:53 +01:00