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| -rw-r--r-- | Documentation/core-api/idr.rst | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/Documentation/core-api/idr.rst b/Documentation/core-api/idr.rst index a2738050c4f0..18d724867064 100644 --- a/Documentation/core-api/idr.rst +++ b/Documentation/core-api/idr.rst @@ -17,51 +17,54 @@ solution to the problem to avoid everybody inventing their own. The IDR provides the ability to map an ID to a pointer, while the IDA provides only ID allocation, and as a result is much more memory-efficient. +The IDR interface is deprecated; please use the :doc:`XArray <xarray>` +instead. + 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 |