[RFC PATCH 0/1] dmaengine: apple-admac: should manual unbind be disabled?

This RFC asks whether manual unbind of the apple-admac DMA controller
should be disabled.

apple-admac stores its dma_device and channels in devm-managed memory and
does not implement dma_device.device_release. At registration, the
DMAengine core emits a diagnostic that the driver is not safe to unbind
while in use, and on channel unregister it emits WARN_ONCE if a channel
still has clients. admac_data is released by devres after admac_remove()
returns, so if a client still holds a channel at that point it may
reference the freed dma_chan and admac_data.

As the controller is a fixed SoC resource, the patch removes the standard
driver-core sysfs bind/unbind controls. It also opts the driver out of
CONFIG_DEBUG_TEST_DRIVER_REMOVE.

This RFC does not define behavior for other removal paths, such as
device or DT-overlay removal. Guidance is requested on whether this
restriction is appropriate, or whether the driver should retain manual
bind/unbind support.

This issue was found by an in-house static analysis tool.


Fan Wu (1):
  dmaengine: apple-admac: suppress bind/unbind sysfs attributes

 drivers/dma/apple-admac.c | 1 +
 1 file changed, 1 insertion(+)

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2.34.1