linux-dev/drivers/pci/iov.c, branch linus/master

PCI/IOV: Fix wrong kernel-doc identifier

2022-03-07T19:06:10Z

Replace "-" to be ":" in comment section to be aligned with kernel-doc format. drivers/pci/iov.c:67: warning: Function parameter or member 'dev' not described in 'pci_iov_get_pf_drvdata' drivers/pci/iov.c:67: warning: Function parameter or member 'pf_driver' not described in 'pci_iov_get_pf_drvdata' Fixes: a7e9f240c0da ("PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata of a PF") Reported-by: Stephen Rothwell Signed-off-by: Leon Romanovsky Acked-by: Randy Dunlap Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/8cecf7df45948a256dc56148cf9e87b2f2bb4198.1646652504.git.leonro@nvidia.com Signed-off-by: Alex Williamson

PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata of a PF

2022-02-27T09:40:58Z

There are some cases where a SR-IOV VF driver will need to reach into and interact with the PF driver. This requires accessing the drvdata of the PF. Provide a function pci_iov_get_pf_drvdata() to return this PF drvdata in a safe way. Normally accessing a drvdata of a foreign struct device would be done using the device_lock() to protect against device driver probe()/remove() races. However, due to the design of pci_enable_sriov() this will result in a ABBA deadlock on the device_lock as the PF's device_lock is held during PF sriov_configure() while calling pci_enable_sriov() which in turn holds the VF's device_lock while calling VF probe(), and similarly for remove. This means the VF driver can never obtain the PF's device_lock. Instead use the implicit locking created by pci_enable/disable_sriov(). A VF driver can access its PF drvdata only while its own driver is attached, and the PF driver can control access to its own drvdata based on when it calls pci_enable/disable_sriov(). To use this API the PF driver will setup the PF drvdata in the probe() function. pci_enable_sriov() is only called from sriov_configure() which cannot happen until probe() completes, ensuring no VF races with drvdata setup. For removal, the PF driver must call pci_disable_sriov() in its remove function before destroying any of the drvdata. This ensures that all VF drivers are unbound before returning, fencing concurrent access to the drvdata. The introduction of a new function to do this access makes clear the special locking scheme and the documents the requirements on the PF/VF drivers using this. Link: https://lore.kernel.org/all/20220224142024.147653-5-yishaih@nvidia.com Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Signed-off-by: Yishai Hadas Signed-off-by: Leon Romanovsky

PCI/IOV: Add pci_iov_vf_id() to get VF index

2022-02-27T09:38:51Z

The PCI core uses the VF index internally, often called the vf_id, during the setup of the VF, eg pci_iov_add_virtfn(). This index is needed for device drivers that implement live migration for their internal operations that configure/control their VFs. Specifically, mlx5_vfio_pci driver that is introduced in coming patches from this series needs it and not the bus/device/function which is exposed today. Add pci_iov_vf_id() which computes the vf_id by reversing the math that was used to create the bus/device/function. Link: https://lore.kernel.org/all/20220224142024.147653-2-yishaih@nvidia.com Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Signed-off-by: Yishai Hadas Signed-off-by: Leon Romanovsky

Revert "PCI: Use to_pci_driver() instead of pci_dev->driver"

2021-11-11T19:36:22Z

This reverts commit 2a4d9408c9e8b6f6fc150c66f3fef755c9e20d4a. Robert reported a NULL pointer dereference caused by the PCI core (local_pci_probe()) calling the i2c_designware_pci driver's .runtime_resume() method before the .probe() method. i2c_dw_pci_resume() depends on initialization done by i2c_dw_pci_probe(). Prior to 2a4d9408c9e8 ("PCI: Use to_pci_driver() instead of pci_dev->driver"), pci_pm_runtime_resume() avoided calling the .runtime_resume() method because pci_dev->driver had not been set yet. 2a4d9408c9e8 and b5f9c644eb1b ("PCI: Remove struct pci_dev->driver"), removed pci_dev->driver, replacing it by device->driver, which *has* been set by this time, so pci_pm_runtime_resume() called the .runtime_resume() method when it previously had not. Fixes: 2a4d9408c9e8 ("PCI: Use to_pci_driver() instead of pci_dev->driver") Link: https://lore.kernel.org/linux-i2c/CAP145pgdrdiMAT7=-iB1DMgA7t_bMqTcJL4N0=6u8kNY3EU0dw@mail.gmail.com/ Reported-by: Robert Święcki Tested-by: Robert Święcki Signed-off-by: Bjorn Helgaas

Merge branch 'pci/sysfs'

2021-11-05T16:28:46Z

- Check for CAP_SYS_ADMIN before validating sysfs user input, not after (Krzysztof Wilczyński) - Always return -EINVAL from sysfs "store" functions for invalid user input instead of -EINVAL sometimes and -ERANGE others (Krzysztof Wilczyński) - Use kstrtobool() directly instead of the strtobool() wrapper (Krzysztof Wilczyński) * pci/sysfs: PCI: Use kstrtobool() directly, sans strtobool() wrapper PCI/sysfs: Return -EINVAL consistently from "store" functions PCI/sysfs: Check CAP_SYS_ADMIN before parsing user input # Conflicts: # drivers/pci/iov.c

PCI: Use to_pci_driver() instead of pci_dev->driver

2021-10-18T14:20:15Z

Struct pci_driver contains a struct device_driver, so for PCI devices, it's easy to convert a device_driver * to a pci_driver * with to_pci_driver(). The device_driver * is in struct device, so we don't need to also keep track of the pci_driver * in struct pci_dev. Replace pci_dev->driver with to_pci_driver(). This is a step toward removing pci_dev->driver. [bhelgaas: split to separate patch] Link: https://lore.kernel.org/r/20211004125935.2300113-11-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Bjorn Helgaas

PCI/sysfs: Return -EINVAL consistently from "store" functions

2021-09-28T22:47:04Z

Most of the "store" functions that handle userspace input via sysfs return -EINVAL should the value fail validation and/or type conversion. This error code is a clear message to userspace that the value is not a valid input. However, some of the "show" functions return input parsing error codes as-is, which may be either -EINVAL or -ERANGE. The former would often be from kstrtobool(), and the latter typically from other kstr*() functions such as kstrtou8(), kstrtou32(), kstrtoint(), etc. -EINVAL is commonly returned as the error code to indicate that the value provided is invalid, but -ERANGE is not very useful in userspace. Therefore, normalize the return error code to be -EINVAL for when the validation and/or type conversion fails. Link: https://lore.kernel.org/r/20210915230127.2495723-2-kw@linux.com Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas

Merge branch 'pci/virtualization'

2021-07-06T15:56:26Z

- Clarify error message for unbound devices (Moritz Fischer) * pci/virtualization: PCI/IOV: Clarify error message for unbound devices

PCI/IOV: Clarify error message for unbound devices

2021-06-10T20:25:38Z

Be more verbose to disambiguate the error case when trying to configure SR-IOV with no driver bound vs. a driver that does not implement the .sriov_configure() callback. Link: https://lore.kernel.org/r/20210327175140.682708-1-mdf@kernel.org Reported-by: Brian Foley Signed-off-by: Moritz Fischer Signed-off-by: Bjorn Helgaas Reviewed-by: Krzysztof Wilczyński

PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions

2021-06-04T03:14:47Z

The sysfs_emit() and sysfs_emit_at() functions were introduced to make it less ambiguous which function is preferred when writing to the output buffer in a device attribute's "show" callback [1]. Convert the PCI sysfs object "show" functions from sprintf(), snprintf() and scnprintf() to sysfs_emit() and sysfs_emit_at() accordingly, as the latter is aware of the PAGE_SIZE buffer and correctly returns the number of bytes written into the buffer. No functional change intended. [1] Documentation/filesystems/sysfs.rst Related commit: ad025f8e46f3 ("PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions"). Link: https://lore.kernel.org/r/20210603000112.703037-2-kw@linux.com Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas Reviewed-by: Logan Gunthorpe