Core-api: Documentation: Replace deprecated :c:func: Usage

IDR usage

=========

Start by initialising an IDR, either with :c:func:`DEFINE_IDR`

for statically allocated IDRs or :c:func:`idr_init` for dynamically

Start by initialising an IDR, either with DEFINE_IDR()

for statically allocated IDRs or idr_init() for dynamically

allocated IDRs.

You can call :c:func:`idr_alloc` to allocate an unused ID.  Look up

the pointer you associated with the ID by calling :c:func:`idr_find`

and free the ID by calling :c:func:`idr_remove`.

You can call idr_alloc() to allocate an unused ID.  Look up

the pointer you associated with the ID by calling idr_find()

and free the ID by calling idr_remove().

If you need to change the pointer associated with an ID, you can call

:c:func:`idr_replace`.  One common reason to do this is to reserve an

idr_replace().  One common reason to do this is to reserve an

ID by passing a ``NULL`` pointer to the allocation function; initialise the

object with the reserved ID and finally insert the initialised object

into the IDR.

Some users need to allocate IDs larger than ``INT_MAX``.  So far all of

these users have been content with a ``UINT_MAX`` limit, and they use

:c:func:`idr_alloc_u32`.  If you need IDs that will not fit in a u32,

idr_alloc_u32().  If you need IDs that will not fit in a u32,

we will work with you to address your needs.

If you need to allocate IDs sequentially, you can use

:c:func:`idr_alloc_cyclic`.  The IDR becomes less efficient when dealing

idr_alloc_cyclic().  The IDR becomes less efficient when dealing

with larger IDs, so using this function comes at a slight cost.

To perform an action on all pointers used by the IDR, you can

either use the callback-based :c:func:`idr_for_each` or the

iterator-style :c:func:`idr_for_each_entry`.  You may need to use

:c:func:`idr_for_each_entry_continue` to continue an iteration.  You can

also use :c:func:`idr_get_next` if the iterator doesn't fit your needs.

either use the callback-based idr_for_each() or the

iterator-style idr_for_each_entry().  You may need to use

idr_for_each_entry_continue() to continue an iteration.  You can

also use idr_get_next() if the iterator doesn't fit your needs.

When you have finished using an IDR, you can call :c:func:`idr_destroy`

When you have finished using an IDR, you can call idr_destroy()

to release the memory used by the IDR.  This will not free the objects

pointed to from the IDR; if you want to do that, use one of the iterators

to do it.

You can use :c:func:`idr_is_empty` to find out whether there are any

You can use idr_is_empty() to find out whether there are any

IDs currently allocated.

If you need to take a lock while allocating a new ID from the IDR,

you may need to pass a restrictive set of GFP flags, which can lead

to the IDR being unable to allocate memory.  To work around this,

you can call :c:func:`idr_preload` before taking the lock, and then

:c:func:`idr_preload_end` after the allocation.

you can call idr_preload() before taking the lock, and then

idr_preload_end() after the allocation.

.. kernel-doc:: include/linux/idr.h

   :doc: idr sync