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

Replace :c:func: with func() as the previous usage is deprecated.
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20200810183019.22170-1-puranjay12@gmail.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/core-api/idr.rst

@@ -20,48 +20,48 @@ only ID allocation, and as a result is much more memory-efficient.
 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