diff options
Diffstat (limited to 'lib/xarray.c')
| -rw-r--r-- | lib/xarray.c | 268 |
1 files changed, 246 insertions, 22 deletions
diff --git a/lib/xarray.c b/lib/xarray.c index 1d9fab7db8da..ea9ce1f0b386 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -157,7 +157,7 @@ static void xas_move_index(struct xa_state *xas, unsigned long offset) xas->xa_index += offset << shift; } -static void xas_advance(struct xa_state *xas) +static void xas_next_offset(struct xa_state *xas) { xas->xa_offset++; xas_move_index(xas, xas->xa_offset); @@ -207,6 +207,8 @@ static void *xas_descend(struct xa_state *xas, struct xa_node *node) if (xa_is_sibling(entry)) { offset = xa_to_sibling(entry); entry = xa_entry(xas->xa, node, offset); + if (node->shift && xa_is_node(entry)) + entry = XA_RETRY_ENTRY; } xas->xa_offset = offset; @@ -262,17 +264,19 @@ static void xa_node_free(struct xa_node *node) * xas_destroy() - Free any resources allocated during the XArray operation. * @xas: XArray operation state. * - * This function is now internal-only. + * Most users will not need to call this function; it is called for you + * by xas_nomem(). */ -static void xas_destroy(struct xa_state *xas) +void xas_destroy(struct xa_state *xas) { - struct xa_node *node = xas->xa_alloc; + struct xa_node *next, *node = xas->xa_alloc; - if (!node) - return; - XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); - kmem_cache_free(radix_tree_node_cachep, node); - xas->xa_alloc = NULL; + while (node) { + XA_NODE_BUG_ON(node, !list_empty(&node->private_list)); + next = rcu_dereference_raw(node->parent); + radix_tree_node_rcu_free(&node->rcu_head); + xas->xa_alloc = node = next; + } } /** @@ -301,9 +305,10 @@ bool xas_nomem(struct xa_state *xas, gfp_t gfp) } if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT) gfp |= __GFP_ACCOUNT; - xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp); if (!xas->xa_alloc) return false; + xas->xa_alloc->parent = NULL; XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); xas->xa_node = XAS_RESTART; return true; @@ -332,13 +337,14 @@ static bool __xas_nomem(struct xa_state *xas, gfp_t gfp) gfp |= __GFP_ACCOUNT; if (gfpflags_allow_blocking(gfp)) { xas_unlock_type(xas, lock_type); - xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp); xas_lock_type(xas, lock_type); } else { - xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp); + xas->xa_alloc = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp); } if (!xas->xa_alloc) return false; + xas->xa_alloc->parent = NULL; XA_NODE_BUG_ON(xas->xa_alloc, !list_empty(&xas->xa_alloc->private_list)); xas->xa_node = XAS_RESTART; return true; @@ -368,7 +374,7 @@ static void *xas_alloc(struct xa_state *xas, unsigned int shift) if (xas->xa->xa_flags & XA_FLAGS_ACCOUNT) gfp |= __GFP_ACCOUNT; - node = kmem_cache_alloc(radix_tree_node_cachep, gfp); + node = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp); if (!node) { xas_set_err(xas, -ENOMEM); return NULL; @@ -403,7 +409,7 @@ static unsigned long xas_size(const struct xa_state *xas) /* * Use this to calculate the maximum index that will need to be created * in order to add the entry described by @xas. Because we cannot store a - * multiple-index entry at index 0, the calculation is a little more complex + * multi-index entry at index 0, the calculation is a little more complex * than you might expect. */ static unsigned long xas_max(struct xa_state *xas) @@ -703,7 +709,7 @@ void xas_create_range(struct xa_state *xas) unsigned char shift = xas->xa_shift; unsigned char sibs = xas->xa_sibs; - xas->xa_index |= ((sibs + 1) << shift) - 1; + xas->xa_index |= ((sibs + 1UL) << shift) - 1; if (xas_is_node(xas) && xas->xa_node->shift == xas->xa_shift) xas->xa_offset |= sibs; xas->xa_shift = 0; @@ -719,6 +725,8 @@ void xas_create_range(struct xa_state *xas) for (;;) { struct xa_node *node = xas->xa_node; + if (node->shift >= shift) + break; xas->xa_node = xa_parent_locked(xas->xa, node); xas->xa_offset = node->offset - 1; if (node->offset != 0) @@ -946,6 +954,156 @@ void xas_init_marks(const struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_init_marks); +#ifdef CONFIG_XARRAY_MULTI +static unsigned int node_get_marks(struct xa_node *node, unsigned int offset) +{ + unsigned int marks = 0; + xa_mark_t mark = XA_MARK_0; + + for (;;) { + if (node_get_mark(node, offset, mark)) + marks |= 1 << (__force unsigned int)mark; + if (mark == XA_MARK_MAX) + break; + mark_inc(mark); + } + + return marks; +} + +static void node_set_marks(struct xa_node *node, unsigned int offset, + struct xa_node *child, unsigned int marks) +{ + xa_mark_t mark = XA_MARK_0; + + for (;;) { + if (marks & (1 << (__force unsigned int)mark)) { + node_set_mark(node, offset, mark); + if (child) + node_mark_all(child, mark); + } + if (mark == XA_MARK_MAX) + break; + mark_inc(mark); + } +} + +/** + * xas_split_alloc() - Allocate memory for splitting an entry. + * @xas: XArray operation state. + * @entry: New entry which will be stored in the array. + * @order: Current entry order. + * @gfp: Memory allocation flags. + * + * This function should be called before calling xas_split(). + * If necessary, it will allocate new nodes (and fill them with @entry) + * to prepare for the upcoming split of an entry of @order size into + * entries of the order stored in the @xas. + * + * Context: May sleep if @gfp flags permit. + */ +void xas_split_alloc(struct xa_state *xas, void *entry, unsigned int order, + gfp_t gfp) +{ + unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; + unsigned int mask = xas->xa_sibs; + + /* XXX: no support for splitting really large entries yet */ + if (WARN_ON(xas->xa_shift + 2 * XA_CHUNK_SHIFT < order)) + goto nomem; + if (xas->xa_shift + XA_CHUNK_SHIFT > order) + return; + + do { + unsigned int i; + void *sibling = NULL; + struct xa_node *node; + + node = kmem_cache_alloc_lru(radix_tree_node_cachep, xas->xa_lru, gfp); + if (!node) + goto nomem; + node->array = xas->xa; + for (i = 0; i < XA_CHUNK_SIZE; i++) { + if ((i & mask) == 0) { + RCU_INIT_POINTER(node->slots[i], entry); + sibling = xa_mk_sibling(i); + } else { + RCU_INIT_POINTER(node->slots[i], sibling); + } + } + RCU_INIT_POINTER(node->parent, xas->xa_alloc); + xas->xa_alloc = node; + } while (sibs-- > 0); + + return; +nomem: + xas_destroy(xas); + xas_set_err(xas, -ENOMEM); +} +EXPORT_SYMBOL_GPL(xas_split_alloc); + +/** + * xas_split() - Split a multi-index entry into smaller entries. + * @xas: XArray operation state. + * @entry: New entry to store in the array. + * @order: Current entry order. + * + * The size of the new entries is set in @xas. The value in @entry is + * copied to all the replacement entries. + * + * Context: Any context. The caller should hold the xa_lock. + */ +void xas_split(struct xa_state *xas, void *entry, unsigned int order) +{ + unsigned int sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; + unsigned int offset, marks; + struct xa_node *node; + void *curr = xas_load(xas); + int values = 0; + + node = xas->xa_node; + if (xas_top(node)) + return; + + marks = node_get_marks(node, xas->xa_offset); + + offset = xas->xa_offset + sibs; + do { + if (xas->xa_shift < node->shift) { + struct xa_node *child = xas->xa_alloc; + + xas->xa_alloc = rcu_dereference_raw(child->parent); + child->shift = node->shift - XA_CHUNK_SHIFT; + child->offset = offset; + child->count = XA_CHUNK_SIZE; + child->nr_values = xa_is_value(entry) ? + XA_CHUNK_SIZE : 0; + RCU_INIT_POINTER(child->parent, node); + node_set_marks(node, offset, child, marks); + rcu_assign_pointer(node->slots[offset], + xa_mk_node(child)); + if (xa_is_value(curr)) + values--; + xas_update(xas, child); + } else { + unsigned int canon = offset - xas->xa_sibs; + + node_set_marks(node, canon, NULL, marks); + rcu_assign_pointer(node->slots[canon], entry); + while (offset > canon) + rcu_assign_pointer(node->slots[offset--], + xa_mk_sibling(canon)); + values += (xa_is_value(entry) - xa_is_value(curr)) * + (xas->xa_sibs + 1); + } + } while (offset-- > xas->xa_offset); + + node->nr_values += values; + xas_update(xas, node); +} +EXPORT_SYMBOL_GPL(xas_split); +#endif + /** * xas_pause() - Pause a walk to drop a lock. * @xas: XArray operation state. @@ -970,7 +1128,7 @@ void xas_pause(struct xa_state *xas) xas->xa_node = XAS_RESTART; if (node) { - unsigned int offset = xas->xa_offset; + unsigned long offset = xas->xa_offset; while (++offset < XA_CHUNK_SIZE) { if (!xa_is_sibling(xa_entry(xas->xa, node, offset))) break; @@ -1099,7 +1257,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1; } - xas_advance(xas); + xas_next_offset(xas); while (xas->xa_node && (xas->xa_index <= max)) { if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) { @@ -1117,7 +1275,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) if (entry && !xa_is_sibling(entry)) return entry; - xas_advance(xas); + xas_next_offset(xas); } if (!xas->xa_node) @@ -1208,6 +1366,8 @@ void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark) } entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!entry && !(xa_track_free(xas->xa) && mark == XA_FREE_MARK)) + continue; if (!xa_is_node(entry)) return entry; xas->xa_node = xa_to_node(entry); @@ -1405,7 +1565,7 @@ EXPORT_SYMBOL(__xa_store); * @gfp: Memory allocation flags. * * After this function returns, loads from this index will return @entry. - * Storing into an existing multislot entry updates the entry of every index. + * Storing into an existing multi-index entry updates the entry of every index. * The marks associated with @index are unaffected unless @entry is %NULL. * * Context: Any context. Takes and releases the xa_lock. @@ -1547,7 +1707,7 @@ static void xas_set_range(struct xa_state *xas, unsigned long first, * * After this function returns, loads from any index between @first and @last, * inclusive will return @entry. - * Storing into an existing multislot entry updates the entry of every index. + * Storing into an existing multi-index entry updates the entry of every index. * The marks associated with @index are unaffected unless @entry is %NULL. * * Context: Process context. Takes and releases the xa_lock. May sleep @@ -1590,6 +1750,46 @@ unlock: return xas_result(&xas, NULL); } EXPORT_SYMBOL(xa_store_range); + +/** + * xa_get_order() - Get the order of an entry. + * @xa: XArray. + * @index: Index of the entry. + * + * Return: A number between 0 and 63 indicating the order of the entry. + */ +int xa_get_order(struct xarray *xa, unsigned long index) +{ + XA_STATE(xas, xa, index); + void *entry; + int order = 0; + + rcu_read_lock(); + entry = xas_load(&xas); + + if (!entry) + goto unlock; + + if (!xas.xa_node) + goto unlock; + + for (;;) { + unsigned int slot = xas.xa_offset + (1 << order); + + if (slot >= XA_CHUNK_SIZE) + break; + if (!xa_is_sibling(xas.xa_node->slots[slot])) + break; + order++; + } + + order += xas.xa_node->shift; +unlock: + rcu_read_unlock(); + + return order; +} +EXPORT_SYMBOL(xa_get_order); #endif /* CONFIG_XARRAY_MULTI */ /** @@ -1836,10 +2036,11 @@ static bool xas_sibling(struct xa_state *xas) struct xa_node *node = xas->xa_node; unsigned long mask; - if (!node) + if (!IS_ENABLED(CONFIG_XARRAY_MULTI) || !node) return false; mask = (XA_CHUNK_SIZE << node->shift) - 1; - return (xas->xa_index & mask) > (xas->xa_offset << node->shift); + return (xas->xa_index & mask) > + ((unsigned long)xas->xa_offset << node->shift); } /** @@ -1971,6 +2172,29 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, EXPORT_SYMBOL(xa_extract); /** + * xa_delete_node() - Private interface for workingset code. + * @node: Node to be removed from the tree. + * @update: Function to call to update ancestor nodes. + * + * Context: xa_lock must be held on entry and will not be released. + */ +void xa_delete_node(struct xa_node *node, xa_update_node_t update) +{ + struct xa_state xas = { + .xa = node->array, + .xa_index = (unsigned long)node->offset << + (node->shift + XA_CHUNK_SHIFT), + .xa_shift = node->shift + XA_CHUNK_SHIFT, + .xa_offset = node->offset, + .xa_node = xa_parent_locked(node->array, node), + .xa_update = update, + }; + + xas_store(&xas, NULL); +} +EXPORT_SYMBOL_GPL(xa_delete_node); /* For the benefit of the test suite */ + +/** * xa_destroy() - Free all internal data structures. * @xa: XArray. * |