kernel/linux.git/include/linux/device.h, branch v4.19.310

Revert "driver core: Annotate dev_err_probe() with __must_check"

2024-02-23T07:12:40+00:00

commit f601e8f37c2c1c52f2923fffc48204a7f7dc023d upstream. This reverts commit e1f82a0dcf388d98bcc7ad195c03bd812405e6b2 as it's already starting to cause build warnings in linux-next for things that are "obviously correct". It's up to driver authors do "do the right thing" here with this function, and if they don't want to call it as the last line of a function, that's up to them, otherwise code that looks like: ret = dev_err_probe(..., ret, ...); does look really "odd". Reported-by: Stephen Rothwell Reported-by: Krzysztof Kozlowski Fixes: e1f82a0dcf38 ("driver core: Annotate dev_err_probe() with __must_check") Cc: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman

driver core: Annotate dev_err_probe() with __must_check

2024-02-23T07:12:40+00:00

commit e1f82a0dcf388d98bcc7ad195c03bd812405e6b2 upstream. We have got already new users of this API which interpret it differently and miss the opportunity to optimize their code. In order to avoid similar cases in the future, annotate dev_err_probe() with __must_check. Fixes: a787e5400a1c ("driver core: add device probe log helper") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200826104459.81979-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman

driver core: add device probe log helper

2024-02-23T07:12:39+00:00

[ Upstream commit a787e5400a1ceeb0ef92d71ec43aeb35b1fa1334 ] During probe every time driver gets resource it should usually check for error printk some message if it is not -EPROBE_DEFER and return the error. This pattern is simple but requires adding few lines after any resource acquisition code, as a result it is often omitted or implemented only partially. dev_err_probe helps to replace such code sequences with simple call, so code: if (err != -EPROBE_DEFER) dev_err(dev, ...); return err; becomes: return dev_err_probe(dev, err, ...); Signed-off-by: Andrzej Hajda Reviewed-by: Rafael J. Wysocki Reviewed-by: Mark Brown Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200713144324.23654-2-a.hajda@samsung.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 6d710b769c1f ("serial: sc16is7xx: add check for unsupported SPI modes during probe") Signed-off-by: Sasha Levin

driver: platform: Add helper for safer setting of driver_override

2023-11-08T10:22:18+00:00

commit 6c2f421174273de8f83cde4286d1c076d43a2d35 upstream. Several core drivers and buses expect that driver_override is a dynamically allocated memory thus later they can kfree() it. However such assumption is not documented, there were in the past and there are already users setting it to a string literal. This leads to kfree() of static memory during device release (e.g. in error paths or during unbind): kernel BUG at ../mm/slub.c:3960! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... (kfree) from [] (platform_device_release+0x88/0xb4) (platform_device_release) from [] (device_release+0x2c/0x90) (device_release) from [] (kobject_put+0xec/0x20c) (kobject_put) from [] (exynos5_clk_probe+0x154/0x18c) (exynos5_clk_probe) from [] (platform_drv_probe+0x6c/0xa4) (platform_drv_probe) from [] (really_probe+0x280/0x414) (really_probe) from [] (driver_probe_device+0x78/0x1c4) (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8) (bus_for_each_drv) from [] (__device_attach+0xd4/0x16c) (__device_attach) from [] (bus_probe_device+0x88/0x90) (bus_probe_device) from [] (device_add+0x3dc/0x62c) (device_add) from [] (of_platform_device_create_pdata+0x94/0xbc) (of_platform_device_create_pdata) from [] (of_platform_bus_create+0x1a8/0x4fc) (of_platform_bus_create) from [] (of_platform_bus_create+0x20c/0x4fc) (of_platform_bus_create) from [] (of_platform_populate+0x84/0x118) (of_platform_populate) from [] (of_platform_default_populate_init+0xa0/0xb8) (of_platform_default_populate_init) from [] (do_one_initcall+0x8c/0x404) Provide a helper which clearly documents the usage of driver_override. This will allow later to reuse the helper and reduce the amount of duplicated code. Convert the platform driver to use a new helper and make the driver_override field const char (it is not modified by the core). Reviewed-by: Rafael J. Wysocki Acked-by: Rafael J. Wysocki Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20220419113435.246203-2-krzysztof.kozlowski@linaro.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman

PCI/MSI: Protect msi_desc::masked for multi-MSI

2021-08-26T12:36:41+00:00

commit 77e89afc25f30abd56e76a809ee2884d7c1b63ce upstream. Multi-MSI uses a single MSI descriptor and there is a single mask register when the device supports per vector masking. To avoid reading back the mask register the value is cached in the MSI descriptor and updates are done by clearing and setting bits in the cache and writing it to the device. But nothing protects msi_desc::masked and the mask register from being modified concurrently on two different CPUs for two different Linux interrupts which belong to the same multi-MSI descriptor. Add a lock to struct device and protect any operation on the mask and the mask register with it. This makes the update of msi_desc::masked unconditional, but there is no place which requires a modification of the hardware register without updating the masked cache. msi_mask_irq() is now an empty wrapper which will be cleaned up in follow up changes. The problem goes way back to the initial support of multi-MSI, but picking the commit which introduced the mask cache is a valid cut off point (2.6.30). Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Signed-off-by: Thomas Gleixner Tested-by: Marc Zyngier Reviewed-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.726833414@linutronix.de Signed-off-by: Greg Kroah-Hartman

driver core: Remove device link creation limitation

2020-03-20T10:55:58+00:00

commit 515db266a9dace92b0cbaed9a6044dd5304b8ca9 upstream. If device_link_add() is called for a consumer/supplier pair with an existing device link between them and the existing link's type is not in agreement with the flags passed to that function by its caller, NULL will be returned. That is seriously inconvenient, because it forces the callers of device_link_add() to worry about what others may or may not do even if that is not relevant to them for any other reasons. It turns out, however, that this limitation can be made go away relatively easily. The underlying observation is that if DL_FLAG_STATELESS has been passed to device_link_add() in flags for the given consumer/supplier pair at least once, calling either device_link_del() or device_link_remove() to release the link returned by it should work, but there are no other requirements associated with that flag. In turn, if at least one of the callers of device_link_add() for the given consumer/supplier pair has not passed DL_FLAG_STATELESS to it in flags, the driver core should track the status of the link and act on it as appropriate (ie. the link should be treated as "managed"). This means that DL_FLAG_STATELESS needs to be set for managed device links and it should be valid to call device_link_del() or device_link_remove() to drop references to them in certain sutiations. To allow that to happen, introduce a new (internal) device link flag called DL_FLAG_MANAGED and make device_link_add() set it automatically whenever DL_FLAG_STATELESS is not passed to it. Also make it take additional references to existing device links that were previously stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED unset) and will need to be managed going forward and initialize their status (which has been DL_STATE_NONE so far). Accordingly, when a managed device link is dropped automatically by the driver core, make it clear DL_FLAG_MANAGED, reset the link's status back to DL_STATE_NONE and drop the reference to it associated with DL_FLAG_MANAGED instead of just deleting it right away (to allow it to stay around in case it still needs to be released explicitly by someone). With that, since setting DL_FLAG_STATELESS doesn't mean that the device link in question is not managed any more, replace all of the status-tracking checks against DL_FLAG_STATELESS with analogous checks against DL_FLAG_MANAGED and update the documentation to reflect these changes. While at it, make device_link_add() reject flags that it does not recognize, including DL_FLAG_MANAGED. Signed-off-by: Rafael J. Wysocki Reviewed-by: Saravana Kannan Tested-by: Marek Szyprowski Review-by: Saravana Kannan Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacher Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

driver core: Add device link flag DL_FLAG_AUTOPROBE_CONSUMER

2020-03-20T10:55:58+00:00

commit e7dd40105aac9ba051e44ad711123bc53a5e4c71 upstream. 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 Signed-off-by: Saravana Kannan Signed-off-by: Greg Kroah-Hartman

devres: allow const resource arguments

2020-01-27T13:51:00+00:00

[ Upstream commit 9dea44c91469512d346e638694c22c30a5273992 ] devm_ioremap_resource() does not currently take 'const' arguments, which results in a warning from the first driver trying to do it anyway: drivers/gpio/gpio-amd-fch.c: In function 'amd_fch_gpio_probe': drivers/gpio/gpio-amd-fch.c:171:49: error: passing argument 2 of 'devm_ioremap_resource' discards 'const' qualifier from pointer target type [-Werror=discarded-qualifiers] priv->base = devm_ioremap_resource(&pdev->dev, &amd_fch_gpio_iores); ^~~~~~~~~~~~~~~~~~~ Change the prototype to allow it, as there is no real reason not to. Fixes: 9bb2e0452508 ("gpio: amd: Make resource struct const") Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20190628150049.1108048-1-arnd@arndb.de Acked-by: Greg Kroah-Hartman Reviwed-By: Enrico Weigelt Signed-off-by: Linus Walleij Signed-off-by: Sasha Levin

driver core: Fix PM-runtime for links added during consumer probe

2020-01-27T13:50:26+00:00

[ Upstream commit 36003d4cf57ca431fb3f94d317bcca426a2394d6 ] Commit 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") introduced a regression that causes suppliers to be suspended prematurely for device links added during consumer driver probe if the initial PM-runtime status of the consumer is "suspended" and the consumer is resumed after adding the link and before pm_runtime_put_suppliers() is called. In that case, pm_runtime_put_suppliers() will drop the rpm_active refcount for the link by one and (since rpm_active is equal to two after the preceding consumer resume) the supplier's PM-runtime usage counter will be decremented, which may cause the supplier to suspend even though the consumer's PM-runtime status is "active". For this reason, partially revert commit 4c06c4e6cf63 as the problem it tried to fix needs to be addressed somewhat differently, and change pm_runtime_get_suppliers() and pm_runtime_put_suppliers() so that the latter only drops rpm_active references acquired by the former. [This requires adding a new field to struct device_link, but I coulnd't find a cleaner way to address the issue that would work in all cases.] This causes pm_runtime_put_suppliers() to effectively ignore device links added during consumer probe, so device_link_add() doesn't need to worry about ensuring that suppliers will remain active after pm_runtime_put_suppliers() for links created with DL_FLAG_RPM_ACTIVE set and it only needs to bump up rpm_active by one for those links, so pm_runtime_active_link() is not necessary any more. Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Reported-by: Jon Hunter Tested-by: Jon Hunter Tested-by: Ulf Hansson Reviewed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki Tested-by: Thierry Reding Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

driver core: Fix handling of runtime PM flags in device_link_add()

2020-01-27T13:50:17+00:00

[ Upstream commit e2f3cd831a280fc226118d9369bf3f77aab58c56 ] After commit ead18c23c263 ("driver core: Introduce device links reference counting"), if there is a link between the given supplier and the given consumer already, device_link_add() will refcount it and return it unconditionally without updating its flags. It is possible, however, that the second (or any subsequent) caller of device_link_add() for the same consumer-supplier pair will pass DL_FLAG_PM_RUNTIME, possibly along with DL_FLAG_RPM_ACTIVE, in flags to it and the existing link may not behave as expected then. First, if DL_FLAG_PM_RUNTIME is not set in the existing link's flags at all, it needs to be set like during the original initialization of the link. Second, if DL_FLAG_RPM_ACTIVE is passed to device_link_add() in flags (in addition to DL_FLAG_PM_RUNTIME), the existing link should to be updated to reflect the "active" runtime PM configuration of the consumer-supplier pair and extra care must be taken here to avoid possible destructive races with runtime PM of the consumer. To that end, redefine the rpm_active field in struct device_link as a refcount, initialize it to 1 and make rpm_resume() (for the consumer) and device_link_add() increment it whenever they acquire a runtime PM reference on the supplier device. Accordingly, make rpm_suspend() (for the consumer) and pm_runtime_clean_up_links() decrement it and drop runtime PM references to the supplier device in a loop until rpm_active becones 1 again. Fixes: ead18c23c263 ("driver core: Introduce device links reference counting") Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin