The 2.6.15 kernel is out. The following is a summary of changes to the
internal kernel API found in this release, with an emphasis on changes
visible to driver writers. This information will be folded into the LWN 2.6 API changes page
- The nested class device
patch was merged, allowing class_device structures to
have other class_devices as parents. This patch is a hack to
make the input subsystem work with sysfs. This code will change again
in the future; see Greg
Kroah-Hartman's article for more information on what is planned.
- The prototypes for the driver model class "interface" methods
add() and remove() have changed; there is now a new
parameter pointing to the relevant interface structure.
- A new platform_driver structure has been added to describe
drivers for devices built into the core "platform."
- The prototypes for the suspend() and resume()
methods in struct device_driver have changed. They are also
only called once per event, rather than three times as in previous
- Two new fields have been added to the device_pm_info which
control how drivers should act on hardware-created wakeup events; see
this article for
- There is a notification mechanism which lets interested modules know
when a USB device is added to (or removed from) the system. This
system is used by some core code; drivers do not normally need to hook
in to it.
- The gfp_t type
is now used throughout the kernel. If you have a function which takes
memory allocation flags, it should probably be using this type.
- Code using reader/writer semaphores can now use
rwsem_is_locked() to test the (read) state of the semaphore
- The new vmalloc_node() function allocates memory on a
specific NUMA node.
- The "reserved" bit for memory pages has, for all practical purposes,
has been added to make it easier for drivers to remap RAM into user
- There is a new kthread_stop_sem() function which can be used
to stop a kernel thread which might be currently blocked on a specific
- RapidIO bus support has
been merged into the mainline.
- The netlink connector
mechanism makes netlink code easier to write. Independently, a
type-safe netlink interface has been added and is used in parts of the
- These kernel symbols have been unexported and are no longer available
to modules: clear_page_dirty_for_io,
user_get_super, uts_sem, vm_acct_memory,
- Version 1 of the Video4Linux API is now officially scheduled for
removal in July, 2006.
- The owner field has been removed from the pci_driver
- A number of SCSI subsystem typedefs (Scsi_Device,
Scsi_Pointer, and Scsi_Host_Template) have been
- The DMA32 memory zone has been added to the x86-64
architecture; its purpose is to make it easy to allocate memory below
the 4GB barrier (with the new GFP_DMA32 flag).
- A call to rcu_barrier() will block the calling process until
all current RCU callbacks have completed.
As can be seen from this list, the kernel API continues to evolve. The
claims of certain well-known maintainers notwithstanding, it doesn't look
like things will slow down much anytime soon.
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