24  * @index is the index of the entry being operated on
30  * @entry refers to something stored in a slot in the xarray
120  * xas_squash_marks() - Merge all marks to the first entry
123  * Set a mark on the first entry if any entry has it set.  Clear marks on
183 	void *entry;  in xas_start()  local
190 	entry = xa_head(xas->xa);  in xas_start()
191 	if (!xa_is_node(entry)) {  in xas_start()
195 		if ((xas->xa_index >> xa_to_node(entry)->shift) > XA_CHUNK_MASK)  in xas_start()
200 	return entry;  in xas_start()
207 	void *entry = xa_entry(xas->xa, node, offset);  in xas_descend()  local
210 	while (xa_is_sibling(entry)) {  in xas_descend()
211 		offset = xa_to_sibling(entry);  in xas_descend()
212 		entry = xa_entry(xas->xa, node, offset);  in xas_descend()
213 		if (node->shift && xa_is_node(entry))  in xas_descend()
214 			entry = XA_RETRY_ENTRY;  in xas_descend()
218 	return entry;  in xas_descend()
222  * xas_load() - Load an entry from the XArray (advanced).
225  * Usually walks the @xas to the appropriate state to load the entry
229  * If the xa_state is set up to operate on a multi-index entry, xas_load()
230  * may return %NULL or an internal entry, even if there are entries
234  * Return: Usually an entry in the XArray, but see description for exceptions.
238 	void *entry = xas_start(xas);  in xas_load()  local
240 	while (xa_is_node(entry)) {  in xas_load()
241 		struct xa_node *node = xa_to_node(entry);  in xas_load()
245 		entry = xas_descend(xas, node);  in xas_load()
249 	return entry;  in xas_load()
410  * in order to add the entry described by @xas.  Because we cannot store a
411  * multi-index entry at index 0, the calculation is a little more complex
431 static unsigned long max_index(void *entry)  in max_index()  argument
433 	if (!xa_is_node(entry))  in max_index()
435 	return (XA_CHUNK_SIZE << xa_to_node(entry)->shift) - 1;  in max_index()
444 		void *entry;  in xas_shrink()  local
449 		entry = xa_entry_locked(xa, node, 0);  in xas_shrink()
450 		if (!entry)  in xas_shrink()
452 		if (!xa_is_node(entry) && node->shift)  in xas_shrink()
454 		if (xa_is_zero(entry) && xa_zero_busy(xa))  in xas_shrink()
455 			entry = NULL;  in xas_shrink()
458 		RCU_INIT_POINTER(xa->xa_head, entry);  in xas_shrink()
464 		if (!xa_is_node(entry))  in xas_shrink()
468 		if (!xa_is_node(entry))  in xas_shrink()
470 		node = xa_to_node(entry);  in xas_shrink()
530 		void *entry = xa_entry_locked(xas->xa, node, offset);  in xas_free_nodes()  local
532 		if (node->shift && xa_is_node(entry)) {  in xas_free_nodes()
533 			node = xa_to_node(entry);  in xas_free_nodes()
537 		if (entry)  in xas_free_nodes()
628  * xas_create() - Create a slot to store an entry in.
630  * @allow_root: %true if we can store the entry in the root directly
643 	void *entry;  in xas_create()  local
650 		entry = xa_head_locked(xa);  in xas_create()
652 		if (!entry && xa_zero_busy(xa))  in xas_create()
653 			entry = XA_ZERO_ENTRY;  in xas_create()
654 		shift = xas_expand(xas, entry);  in xas_create()
659 		entry = xa_head_locked(xa);  in xas_create()
667 		entry = xa_entry_locked(xa, node, offset);  in xas_create()
671 		entry = xa_head_locked(xa);  in xas_create()
677 		if (!entry) {  in xas_create()
684 		} else if (xa_is_node(entry)) {  in xas_create()
685 			node = xa_to_node(entry);  in xas_create()
689 		entry = xas_descend(xas, node);  in xas_create()
693 	return entry;  in xas_create()
764  * xas_store() - Store this entry in the XArray.
766  * @entry: New entry.
768  * If @xas is operating on a multi-index entry, the entry returned by this
769  * function is essentially meaningless (it may be an internal entry or it
774  * Return: The old entry at this index.
776 void *xas_store(struct xa_state *xas, void *entry)  in xas_store()  argument
784 	bool value = xa_is_value(entry);  in xas_store()
786 	if (entry) {  in xas_store()
787 		bool allow_root = !xa_is_node(entry) && !xa_is_zero(entry);  in xas_store()
798 	if ((first == entry) && !xas->xa_sibs)  in xas_store()
809 	if (!entry)  in xas_store()
814 		 * Must clear the marks before setting the entry to NULL,  in xas_store()
815 		 * otherwise xas_for_each_marked may find a NULL entry and  in xas_store()
818 		 * entry is set to NULL.  in xas_store()
820 		rcu_assign_pointer(*slot, entry);  in xas_store()
825 		count += !next - !entry;  in xas_store()
827 		if (entry) {  in xas_store()
830 			if (!xa_is_sibling(entry))  in xas_store()
831 				entry = xa_mk_sibling(xas->xa_offset);  in xas_store()
838 			if (!entry && (offset > max))  in xas_store()
869  * xas_set_mark() - Sets the mark on this entry and its parents.
873  * Sets the specified mark on this entry, and walks up the tree setting it
875  * an entry, or is in an error state.
898  * xas_clear_mark() - Clears the mark on this entry and its parents.
902  * Clears the specified mark on this entry, and walks back to the head
904  * @xas has not been walked to an entry, or is in an error state.
930  * xas_init_marks() - Initialise all marks for the entry
933  * Initialise all marks for the entry specified by @xas.  If we're tracking
1005  * xas_split_alloc() - Allocate memory for splitting an entry.
1007  * @entry: New entry which will be stored in the array.
1008  * @order: Current entry order.
1012  * If necessary, it will allocate new nodes (and fill them with @entry)
1013  * to prepare for the upcoming split of an entry of @order size into
1018 void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order,  in xas_split_alloc()  argument
1041 				RCU_INIT_POINTER(node->slots[i], entry);  in xas_split_alloc()
1059  * xas_split() - Split a multi-index entry into smaller entries.
1061  * @entry: New entry to store in the array.
1062  * @order: Current entry order.
1064  * The size of the new entries is set in @xas.  The value in @entry is
1069 void xas_split(struct xa_state *xas, void *entry, unsigned int order)  in xas_split()  argument
1092 			child->nr_values = xa_is_value(entry) ?  in xas_split()
1106 			rcu_assign_pointer(node->slots[canon], entry);  in xas_split()
1110 			values += (xa_is_value(entry) - xa_is_value(curr)) *  in xas_split()
1127  * on an entry.  Those users should call this function before they drop
1160  * __xas_prev() - Find the previous entry in the XArray.
1168 	void *entry;  in __xas_prev()  local
1188 		entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);  in __xas_prev()
1189 		if (!xa_is_node(entry))  in __xas_prev()
1190 			return entry;  in __xas_prev()
1192 		xas->xa_node = xa_to_node(entry);  in __xas_prev()
1199  * __xas_next() - Find the next entry in the XArray.
1207 	void *entry;  in __xas_next()  local
1227 		entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);  in __xas_next()
1228 		if (!xa_is_node(entry))  in __xas_next()
1229 			return entry;  in __xas_next()
1231 		xas->xa_node = xa_to_node(entry);  in __xas_next()
1238  * xas_find() - Find the next present entry in the XArray.
1242  * If the @xas has not yet been walked to an entry, return the entry
1243  * which has an index >= xas.xa_index.  If it has been walked, the entry
1245  * next entry.
1247  * If no entry is found and the array is smaller than @max, the iterator
1251  * Return: The entry, if found, otherwise %NULL.
1255 	void *entry;  in xas_find()  local
1266 		entry = xas_load(xas);  in xas_find()
1267 		if (entry || xas_not_node(xas->xa_node))  in xas_find()
1268 			return entry;  in xas_find()
1283 		entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);  in xas_find()
1284 		if (xa_is_node(entry)) {  in xas_find()
1285 			xas->xa_node = xa_to_node(entry);  in xas_find()
1289 		if (entry && !xa_is_sibling(entry))  in xas_find()
1290 			return entry;  in xas_find()
1302  * xas_find_marked() - Find the next marked entry in the XArray.
1307  * If the @xas has not yet been walked to an entry, return the marked entry
1308  * which has an index >= xas.xa_index.  If it has been walked, the entry
1310  * first marked entry with an index > xas.xa_index.
1312  * If no marked entry is found and the array is smaller than @max, @xas is
1317  * If no entry is found before @max is reached, @xas is set to the restart
1320  * Return: The entry, if found, otherwise %NULL.
1326 	void *entry;  in xas_find_marked()  local
1338 		entry = xa_head(xas->xa);  in xas_find_marked()
1340 		if (xas->xa_index > max_index(entry))  in xas_find_marked()
1342 		if (!xa_is_node(entry)) {  in xas_find_marked()
1344 				return entry;  in xas_find_marked()
1348 		xas->xa_node = xa_to_node(entry);  in xas_find_marked()
1363 			entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);  in xas_find_marked()
1364 			if (xa_is_sibling(entry)) {  in xas_find_marked()
1365 				xas->xa_offset = xa_to_sibling(entry);  in xas_find_marked()
1382 		entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);  in xas_find_marked()
1383 		if (!entry && !(xa_track_free(xas->xa) && mark == XA_FREE_MARK))  in xas_find_marked()
1385 		if (!xa_is_node(entry))  in xas_find_marked()
1386 			return entry;  in xas_find_marked()
1387 		xas->xa_node = xa_to_node(entry);  in xas_find_marked()
1402  * xas_find_conflict() - Find the next present entry in a range.
1408  * Return: The next entry in the range covered by @xas or %NULL.
1463  * xa_load() - Load an entry from an XArray.
1468  * Return: The entry at @index in @xa.
1473 	void *entry;  in xa_load()  local
1477 		entry = xas_load(&xas);  in xa_load()
1478 		if (xa_is_zero(entry))  in xa_load()
1479 			entry = NULL;  in xa_load()
1480 	} while (xas_retry(&xas, entry));  in xa_load()
1483 	return entry;  in xa_load()
1497  * __xa_erase() - Erase this entry from the XArray while locked.
1502  * If the index is part of a multi-index entry, all indices will be erased
1503  * and none of the entries will be part of a multi-index entry.
1505  * Context: Any context.  Expects xa_lock to be held on entry.
1506  * Return: The entry which used to be at this index.
1516  * xa_erase() - Erase this entry from the XArray.
1518  * @index: Index of entry.
1521  * If the index is part of a multi-index entry, all indices will be erased
1522  * and none of the entries will be part of a multi-index entry.
1525  * Return: The entry which used to be at this index.
1529 	void *entry;  in xa_erase()  local
1532 	entry = __xa_erase(xa, index);  in xa_erase()
1535 	return entry;  in xa_erase()
1540  * __xa_store() - Store this entry in the XArray.
1543  * @entry: New entry.
1550  * Context: Any context.  Expects xa_lock to be held on entry.  May
1552  * Return: The old entry at this index or xa_err() if an error happened.
1554 void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)  in __xa_store()  argument
1559 	if (WARN_ON_ONCE(xa_is_advanced(entry)))  in __xa_store()
1561 	if (xa_track_free(xa) && !entry)  in __xa_store()
1562 		entry = XA_ZERO_ENTRY;  in __xa_store()
1565 		curr = xas_store(&xas, entry);  in __xa_store()
1575  * xa_store() - Store this entry in the XArray.
1578  * @entry: New entry.
1581  * After this function returns, loads from this index will return @entry.
1582  * Storing into an existing multi-index entry updates the entry of every index.
1583  * The marks associated with @index are unaffected unless @entry is %NULL.
1587  * Return: The old entry at this index on success, xa_err(-EINVAL) if @entry
1591 void *xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)  in xa_store()  argument
1596 	curr = __xa_store(xa, index, entry, gfp);  in xa_store()
1604  * __xa_cmpxchg() - Store this entry in the XArray.
1608  * @entry: New entry.
1615  * Context: Any context.  Expects xa_lock to be held on entry.  May
1617  * Return: The old entry at this index or xa_err() if an error happened.
1620 			void *old, void *entry, gfp_t gfp)  in __xa_cmpxchg()  argument
1625 	if (WARN_ON_ONCE(xa_is_advanced(entry)))  in __xa_cmpxchg()
1631 			xas_store(&xas, entry);  in __xa_cmpxchg()
1632 			if (xa_track_free(xa) && entry && !curr)  in __xa_cmpxchg()
1642  * __xa_insert() - Store this entry in the XArray if no entry is present.
1645  * @entry: New entry.
1648  * Inserting a NULL entry will store a reserved entry (like xa_reserve())
1649  * if no entry is present.  Inserting will fail if a reserved entry is
1652  * Context: Any context.  Expects xa_lock to be held on entry.  May
1654  * Return: 0 if the store succeeded.  -EBUSY if another entry was present.
1657 int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)  in __xa_insert()  argument
1662 	if (WARN_ON_ONCE(xa_is_advanced(entry)))  in __xa_insert()
1664 	if (!entry)  in __xa_insert()
1665 		entry = XA_ZERO_ENTRY;  in __xa_insert()
1670 			xas_store(&xas, entry);  in __xa_insert()
1715  * xa_store_range() - Store this entry at a range of indices in the XArray.
1719  * @entry: New entry.
1723  * inclusive will return @entry.
1724  * Storing into an existing multi-index entry updates the entry of every index.
1725  * The marks associated with @index are unaffected unless @entry is %NULL.
1729  * Return: %NULL on success, xa_err(-EINVAL) if @entry cannot be stored in
1733 		unsigned long last, void *entry, gfp_t gfp)  in xa_store_range()  argument
1737 	if (WARN_ON_ONCE(xa_is_internal(entry)))  in xa_store_range()
1744 		if (entry) {  in xa_store_range()
1755 			xas_store(&xas, entry);  in xa_store_range()
1769  * xas_get_order() - Get the order of an entry.
1774  * Return: A number between 0 and 63 indicating the order of the entry.
1799  * xa_get_order() - Get the order of an entry.
1801  * @index: Index of the entry.
1803  * Return: A number between 0 and 63 indicating the order of the entry.
1809 	void *entry;  in xa_get_order()  local
1812 	entry = xas_load(&xas);  in xa_get_order()
1813 	if (entry)  in xa_get_order()
1823  * __xa_alloc() - Find somewhere to store this entry in the XArray.
1827  * @entry: New entry.
1830  * Finds an empty entry in @xa between @limit.min and @limit.max,
1831  * stores the index into the @id pointer, then stores the entry at
1837  * Context: Any context.  Expects xa_lock to be held on entry.  May
1842 int __xa_alloc(struct xarray *xa, u32 *id, void *entry,  in __xa_alloc()  argument
1847 	if (WARN_ON_ONCE(xa_is_advanced(entry)))  in __xa_alloc()
1852 	if (!entry)  in __xa_alloc()
1853 		entry = XA_ZERO_ENTRY;  in __xa_alloc()
1862 		xas_store(&xas, entry);  in __xa_alloc()
1871  * __xa_alloc_cyclic() - Find somewhere to store this entry in the XArray.
1874  * @entry: New entry.
1879  * Finds an empty entry in @xa between @limit.min and @limit.max,
1880  * stores the index into the @id pointer, then stores the entry at
1882  * The search for an empty entry will start at @next and will wrap
1888  * Context: Any context.  Expects xa_lock to be held on entry.  May
1894 int __xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry,  in __xa_alloc_cyclic()  argument
1901 	ret = __xa_alloc(xa, id, entry, limit, gfp);  in __xa_alloc_cyclic()
1909 		ret = __xa_alloc(xa, id, entry, limit, gfp);  in __xa_alloc_cyclic()
1924  * __xa_set_mark() - Set this mark on this entry while locked.
1926  * @index: Index of entry.
1929  * Attempting to set a mark on a %NULL entry does not succeed.
1931  * Context: Any context.  Expects xa_lock to be held on entry.
1936 	void *entry = xas_load(&xas);  in __xa_set_mark()  local
1938 	if (entry)  in __xa_set_mark()
1944  * __xa_clear_mark() - Clear this mark on this entry while locked.
1946  * @index: Index of entry.
1949  * Context: Any context.  Expects xa_lock to be held on entry.
1954 	void *entry = xas_load(&xas);  in __xa_clear_mark()  local
1956 	if (entry)  in __xa_clear_mark()
1962  * xa_get_mark() - Inquire whether this mark is set on this entry.
1964  * @index: Index of entry.
1971  * Return: True if the entry at @index has this mark set, false if it doesn't.
1976 	void *entry;  in xa_get_mark()  local
1979 	entry = xas_start(&xas);  in xa_get_mark()
1981 		if (!xa_is_node(entry))  in xa_get_mark()
1983 		entry = xas_descend(&xas, xa_to_node(entry));  in xa_get_mark()
1994  * xa_set_mark() - Set this mark on this entry.
1996  * @index: Index of entry.
1999  * Attempting to set a mark on a %NULL entry does not succeed.
2012  * xa_clear_mark() - Clear this mark on this entry.
2014  * @index: Index of entry.
2030  * xa_find() - Search the XArray for an entry.
2036  * Finds the entry in @xa which matches the @filter, and has the lowest
2038  * If an entry is found, @indexp is updated to be the index of the entry.
2044  * Return: The entry, if found, otherwise %NULL.
2050 	void *entry;  in xa_find()  local
2055 			entry = xas_find_marked(&xas, max, filter);  in xa_find()
2057 			entry = xas_find(&xas, max);  in xa_find()
2058 	} while (xas_retry(&xas, entry));  in xa_find()
2061 	if (entry)  in xa_find()
2063 	return entry;  in xa_find()
2080  * xa_find_after() - Search the XArray for a present entry.
2086  * Finds the entry in @xa which matches the @filter and has the lowest
2088  * If an entry is found, @indexp is updated to be the index of the entry.
2100 	void *entry;  in xa_find_after()  local
2108 			entry = xas_find_marked(&xas, max, filter);  in xa_find_after()
2110 			entry = xas_find(&xas, max);  in xa_find_after()
2116 		if (!xas_retry(&xas, entry))  in xa_find_after()
2121 	if (entry)  in xa_find_after()
2123 	return entry;  in xa_find_after()
2130 	void *entry;  in xas_extract_present()  local
2134 	xas_for_each(xas, entry, max) {  in xas_extract_present()
2135 		if (xas_retry(xas, entry))  in xas_extract_present()
2137 		dst[i++] = entry;  in xas_extract_present()
2149 	void *entry;  in xas_extract_marked()  local
2153 	xas_for_each_marked(xas, entry, max, mark) {  in xas_extract_marked()
2154 		if (xas_retry(xas, entry))  in xas_extract_marked()
2156 		dst[i++] = entry;  in xas_extract_marked()
2212  * Context: xa_lock must be held on entry and will not be released.
2244 	void *entry;  in xa_destroy()  local
2248 	entry = xa_head_locked(xa);  in xa_destroy()
2254 	if (xa_is_node(entry))  in xa_destroy()
2255 		xas_free_nodes(&xas, xa_to_node(entry));  in xa_destroy()
2293 void xa_dump_entry(const void *entry, unsigned long index, unsigned long shift)  in xa_dump_entry()  argument
2295 	if (!entry)  in xa_dump_entry()
2300 	if (xa_is_node(entry)) {  in xa_dump_entry()
2302 			pr_cont("%px\n", entry);  in xa_dump_entry()
2305 			struct xa_node *node = xa_to_node(entry);  in xa_dump_entry()
2311 	} else if (xa_is_value(entry))  in xa_dump_entry()
2312 		pr_cont("value %ld (0x%lx) [%px]\n", xa_to_value(entry),  in xa_dump_entry()
2313 						xa_to_value(entry), entry);  in xa_dump_entry()
2314 	else if (!xa_is_internal(entry))  in xa_dump_entry()
2315 		pr_cont("%px\n", entry);  in xa_dump_entry()
2316 	else if (xa_is_retry(entry))  in xa_dump_entry()
2317 		pr_cont("retry (%ld)\n", xa_to_internal(entry));  in xa_dump_entry()
2318 	else if (xa_is_sibling(entry))  in xa_dump_entry()
2319 		pr_cont("sibling (slot %ld)\n", xa_to_sibling(entry));  in xa_dump_entry()
2320 	else if (xa_is_zero(entry))  in xa_dump_entry()
2321 		pr_cont("zero (%ld)\n", xa_to_internal(entry));  in xa_dump_entry()
2323 		pr_cont("UNKNOWN ENTRY (%px)\n", entry);  in xa_dump_entry()
2328 	void *entry = xa->xa_head;  in xa_dump()  local
2331 	pr_info("xarray: %px head %px flags %x marks %d %d %d\n", xa, entry,  in xa_dump()
2334 	if (xa_is_node(entry))  in xa_dump()
2335 		shift = xa_to_node(entry)->shift + XA_CHUNK_SHIFT;  in xa_dump()
2336 	xa_dump_entry(entry, 0, shift);  in xa_dump()