The bus_type structure defines dma_configure() callback for bus drivers
to configure DMA on the devices. This adds the paired dma_cleanup()
callback and calls it during driver unbinding so that bus drivers can do
some cleanup work.
One use case for this paired DMA callbacks is for the bus driver to check
for DMA ownership conflicts during driver binding, where multiple devices
belonging to a same IOMMU group (the minimum granularity of isolation and
protection) may be assigned to kernel drivers or user space respectively.
Without this change, for example, the vfio driver has to listen to a bus
BOUND_DRIVER event and then BUG_ON() in case of dma ownership conflict.
This leads to bad user experience since careless driver binding operation
may crash the system if the admin overlooks the group restriction. Aside
from bad design, this leads to a security problem as a root user, even with
lockdown=integrity, can force the kernel to BUG.
With this change, the bus driver could check and set the DMA ownership in
driver binding process and fail on ownership conflicts. The DMA ownership
should be released during driver unbinding.
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>
We have a couple of users of this helper, make it available for them.
The prototype for the helper is specifically crafted in order to be
easily used with bus_find_device() call. That's why its location is
in the driver core rather than ACPI.
Reviewed-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.
This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.
With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.
Reviewed-by: Tom Rix <[email protected]> (For fpga)
Reviewed-by: Mathieu Poirier <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]> (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle) <[email protected]> (For ARM, Amba and related parts)
Acked-by: Mark Brown <[email protected]>
Acked-by: Chen-Yu Tsai <[email protected]> (for sunxi-rsb)
Acked-by: Pali Rohár <[email protected]>
Acked-by: Mauro Carvalho Chehab <[email protected]> (for media)
Acked-by: Hans de Goede <[email protected]> (For drivers/platform)
Acked-by: Alexandre Belloni <[email protected]>
Acked-By: Vinod Koul <[email protected]>
Acked-by: Juergen Gross <[email protected]> (For xen)
Acked-by: Lee Jones <[email protected]> (For mfd)
Acked-by: Johannes Thumshirn <[email protected]> (For mcb)
Acked-by: Johan Hovold <[email protected]>
Acked-by: Srinivas Kandagatla <[email protected]> (For slimbus)
Acked-by: Kirti Wankhede <[email protected]> (For vfio)
Acked-by: Maximilian Luz <[email protected]>
Acked-by: Heikki Krogerus <[email protected]> (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez <[email protected]> (For ipack)
Acked-by: Geoff Levand <[email protected]> (For ps3)
Acked-by: Yehezkel Bernat <[email protected]> (For thunderbolt)
Acked-by: Alexander Shishkin <[email protected]> (For intel_th)
Acked-by: Dominik Brodowski <[email protected]> (For pcmcia)
Acked-by: Rafael J. Wysocki <[email protected]> (For ACPI)
Acked-by: Bjorn Andersson <[email protected]> (rpmsg and apr)
Acked-by: Srinivas Pandruvada <[email protected]> (For intel-ish-hid)
Acked-by: Dan Williams <[email protected]> (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray <[email protected]> (For isa)
Acked-by: Stefan Richter <[email protected]> (For firewire)
Acked-by: Benjamin Tissoires <[email protected]> (For hid)
Acked-by: Thorsten Scherer <[email protected]> (For siox)
Acked-by: Sven Van Asbroeck <[email protected]> (For anybuss)
Acked-by: Ulf Hansson <[email protected]> (For MMC)
Acked-by: Wolfram Sang <[email protected]> # for I2C
Acked-by: Sudeep Holla <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Dmitry Torokhov <[email protected]>
Acked-by: Finn Thain <[email protected]>
Signed-off-by: Uwe Kleine-König <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Lu Baolu