Lines Matching +full:zero +full:- +full:initialised

1 .. SPDX-License-Identifier: GPL-2.0+
15 next or previous entry in a cache-efficient manner.  In contrast to a
17 order to grow the array.  It is more memory-efficient, parallelisable
18 and cache friendly than a doubly-linked list.  It takes advantage of
28 Each non-``NULL`` entry in the array has three bits associated with
32 Normal pointers may be stored in the XArray directly.  They must be 4-byte
34 alloc_page().  It isn't true for arbitrary user-space pointers,
60 Storing to any index will store to all of them.  Multi-index entries can
69 allocated ones.  A freshly-initialised XArray contains a ``NULL``
88 returns ``-EBUSY`` if the entry is not empty.
128 ------------------
156 -----------------
171 -------
239         xa_init_flags(&foo->array, XA_FLAGS_LOCK_BH);
246         xa_lock_bh(&foo->array);
247         err = xa_err(__xa_store(&foo->array, index, entry, GFP_KERNEL));
249             foo->count++;
250         xa_unlock_bh(&foo->array);
257         xa_lock(&foo->array);
258         __xa_erase(&foo->array, index);
259         foo->count--;
260         xa_unlock(&foo->array);
297 to use the xa_lock or the RCU lock while doing read-only operations on
300 advanced API is only available to modules with a GPL-compatible license.
331 ----------------
338 .. flat-table::
341    * - Name
342      - Test
343      - Usage
345    * - Node
346      - xa_is_node()
347      - An XArray node.  May be visible when using a multi-index xa_state.
349    * - Sibling
350      - xa_is_sibling()
351      - A non-canonical entry for a multi-index entry.  The value indicates
354    * - Retry
355      - xa_is_retry()
356      - This entry is currently being modified by a thread which has the
361    * - Zero
362      - xa_is_zero()
363      - Zero entries appear as ``NULL`` through the Normal API, but occupy
372 ------------------------
433 Multi-Index Entries
434 -------------------
442 eg indices 64-127 may be tied together, but 2-6 may not be.  This may
446 You can create a multi-index entry by using XA_STATE_ORDER()
448 Calling xas_load() with a multi-index xa_state will walk the
456 If xas_load() encounters a multi-index entry, the xa_index
459 of a multi-index entry, it will not be altered.  Subsequent calls
464 Using xas_next() or xas_prev() with a multi-index xa_state
465 is not supported.  Using either of these functions on a multi-index entry
468 Storing ``NULL`` into any index of a multi-index entry will set the entry
469 at every index to ``NULL`` and dissolve the tie.  Splitting a multi-index
475 .. kernel-doc:: include/linux/xarray.h
476 .. kernel-doc:: lib/xarray.c