Device-managed resources – Devres

Devres is a kernel facility helping the developer by automatically freeing the allocated resource in a driver. It simplifies errors handling in init/probe/open functions. With Devres, each resource allocator has its managed version that will take care of resource release and freeing for you.

Note

This section heavily relies on the Documentation/driver-model/devres.txt file in the kernel source tree, which deals with the devres API and lists supported functions along with their descriptions.

The memory allocated with resource-managed functions is associated with the device. devres consists of a linked list of arbitrarily sized memory areas associated with a struct device. Each devres resource allocator inserts the allocated resource in the list. The resource remains available until it is manually freed by the code, when the device is detached from the system, or when the driver is unloaded. Each devres entry is associated with a release function. There are different...