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authorIngo Molnar <mingo@kernel.org>2017-11-07 10:32:44 +0100
committerIngo Molnar <mingo@kernel.org>2017-11-07 10:32:44 +0100
commit8c5db92a705d9e2c986adec475980d1120fa07b4 (patch)
tree9f0eea56889819707c0a1a8eb5b1fb2db3cdaf3d /lib/assoc_array.c
parentca5d376e17072c1b60c3fee66f3be58ef018952d (diff)
parente4880bc5dfb1f02b152e62a894b5c6f3e995b3cf (diff)
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Merge branch 'linus' into locking/core, to resolve conflicts
Conflicts: include/linux/compiler-clang.h include/linux/compiler-gcc.h include/linux/compiler-intel.h include/uapi/linux/stddef.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'lib/assoc_array.c')
-rw-r--r--lib/assoc_array.c51
1 files changed, 17 insertions, 34 deletions
diff --git a/lib/assoc_array.c b/lib/assoc_array.c
index fe7953aead82..b77d51da8c73 100644
--- a/lib/assoc_array.c
+++ b/lib/assoc_array.c
@@ -598,21 +598,31 @@ static bool assoc_array_insert_into_terminal_node(struct assoc_array_edit *edit,
if ((edit->segment_cache[ASSOC_ARRAY_FAN_OUT] ^ base_seg) == 0)
goto all_leaves_cluster_together;
- /* Otherwise we can just insert a new node ahead of the old
- * one.
+ /* Otherwise all the old leaves cluster in the same slot, but
+ * the new leaf wants to go into a different slot - so we
+ * create a new node (n0) to hold the new leaf and a pointer to
+ * a new node (n1) holding all the old leaves.
+ *
+ * This can be done by falling through to the node splitting
+ * path.
*/
- goto present_leaves_cluster_but_not_new_leaf;
+ pr_devel("present leaves cluster but not new leaf\n");
}
split_node:
pr_devel("split node\n");
- /* We need to split the current node; we know that the node doesn't
- * simply contain a full set of leaves that cluster together (it
- * contains meta pointers and/or non-clustering leaves).
+ /* We need to split the current node. The node must contain anything
+ * from a single leaf (in the one leaf case, this leaf will cluster
+ * with the new leaf) and the rest meta-pointers, to all leaves, some
+ * of which may cluster.
+ *
+ * It won't contain the case in which all the current leaves plus the
+ * new leaves want to cluster in the same slot.
*
* We need to expel at least two leaves out of a set consisting of the
- * leaves in the node and the new leaf.
+ * leaves in the node and the new leaf. The current meta pointers can
+ * just be copied as they shouldn't cluster with any of the leaves.
*
* We need a new node (n0) to replace the current one and a new node to
* take the expelled nodes (n1).
@@ -717,33 +727,6 @@ found_slot_for_multiple_occupancy:
pr_devel("<--%s() = ok [split node]\n", __func__);
return true;
-present_leaves_cluster_but_not_new_leaf:
- /* All the old leaves cluster in the same slot, but the new leaf wants
- * to go into a different slot, so we create a new node to hold the new
- * leaf and a pointer to a new node holding all the old leaves.
- */
- pr_devel("present leaves cluster but not new leaf\n");
-
- new_n0->back_pointer = node->back_pointer;
- new_n0->parent_slot = node->parent_slot;
- new_n0->nr_leaves_on_branch = node->nr_leaves_on_branch;
- new_n1->back_pointer = assoc_array_node_to_ptr(new_n0);
- new_n1->parent_slot = edit->segment_cache[0];
- new_n1->nr_leaves_on_branch = node->nr_leaves_on_branch;
- edit->adjust_count_on = new_n0;
-
- for (i = 0; i < ASSOC_ARRAY_FAN_OUT; i++)
- new_n1->slots[i] = node->slots[i];
-
- new_n0->slots[edit->segment_cache[0]] = assoc_array_node_to_ptr(new_n0);
- edit->leaf_p = &new_n0->slots[edit->segment_cache[ASSOC_ARRAY_FAN_OUT]];
-
- edit->set[0].ptr = &assoc_array_ptr_to_node(node->back_pointer)->slots[node->parent_slot];
- edit->set[0].to = assoc_array_node_to_ptr(new_n0);
- edit->excised_meta[0] = assoc_array_node_to_ptr(node);
- pr_devel("<--%s() = ok [insert node before]\n", __func__);
- return true;
-
all_leaves_cluster_together:
/* All the leaves, new and old, want to cluster together in this node
* in the same slot, so we have to replace this node with a shortcut to