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authorMatthew Wilcox <willy@infradead.org>2017-11-17 08:16:34 -0500
committerMatthew Wilcox <willy@infradead.org>2018-10-21 10:45:59 -0400
commit687149fca1f37c447e5d161e0a4a04cb2c880cb6 (patch)
tree5134bc243622997b10644a67a55ee51e6278930a
parent80a0a1a9a3cde9b23851e8eb7160e2786549306a (diff)
downloadlinux-687149fca1f37c447e5d161e0a4a04cb2c880cb6.tar.bz2
xarray: Destroy an XArray
This function frees all the internal memory allocated to the xarray and reinitialises it to be empty. Signed-off-by: Matthew Wilcox <willy@infradead.org>
-rw-r--r--include/linux/xarray.h1
-rw-r--r--lib/test_xarray.c34
-rw-r--r--lib/xarray.c28
3 files changed, 63 insertions, 0 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 82ceed981924..0a758fa3ed2c 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -286,6 +286,7 @@ void *xa_find_after(struct xarray *xa, unsigned long *index,
unsigned long max, xa_mark_t) __attribute__((nonnull(2)));
unsigned int xa_extract(struct xarray *, void **dst, unsigned long start,
unsigned long max, unsigned int n, xa_mark_t);
+void xa_destroy(struct xarray *);
/**
* xa_init() - Initialise an empty XArray.
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index e3c2d4d00b15..a96f67caa1c2 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -465,6 +465,39 @@ static noinline void check_find(struct xarray *xa)
check_multi_find_2(xa);
}
+static noinline void check_destroy(struct xarray *xa)
+{
+ unsigned long index;
+
+ XA_BUG_ON(xa, !xa_empty(xa));
+
+ /* Destroying an empty array is a no-op */
+ xa_destroy(xa);
+ XA_BUG_ON(xa, !xa_empty(xa));
+
+ /* Destroying an array with a single entry */
+ for (index = 0; index < 1000; index++) {
+ xa_store_index(xa, index, GFP_KERNEL);
+ XA_BUG_ON(xa, xa_empty(xa));
+ xa_destroy(xa);
+ XA_BUG_ON(xa, !xa_empty(xa));
+ }
+
+ /* Destroying an array with a single entry at ULONG_MAX */
+ xa_store(xa, ULONG_MAX, xa, GFP_KERNEL);
+ XA_BUG_ON(xa, xa_empty(xa));
+ xa_destroy(xa);
+ XA_BUG_ON(xa, !xa_empty(xa));
+
+#ifdef CONFIG_XARRAY_MULTI
+ /* Destroying an array with a multi-index entry */
+ xa_store_order(xa, 1 << 11, 11, xa, GFP_KERNEL);
+ XA_BUG_ON(xa, xa_empty(xa));
+ xa_destroy(xa);
+ XA_BUG_ON(xa, !xa_empty(xa));
+#endif
+}
+
static DEFINE_XARRAY(array);
static int xarray_checks(void)
@@ -478,6 +511,7 @@ static int xarray_checks(void)
check_cmpxchg(&array);
check_multi_store(&array);
check_find(&array);
+ check_destroy(&array);
printk("XArray: %u of %u tests passed\n", tests_passed, tests_run);
return (tests_run == tests_passed) ? 0 : -EINVAL;
diff --git a/lib/xarray.c b/lib/xarray.c
index 70e04810c8c2..057dbe0d3bf6 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1524,6 +1524,34 @@ unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start,
}
EXPORT_SYMBOL(xa_extract);
+/**
+ * xa_destroy() - Free all internal data structures.
+ * @xa: XArray.
+ *
+ * After calling this function, the XArray is empty and has freed all memory
+ * allocated for its internal data structures. You are responsible for
+ * freeing the objects referenced by the XArray.
+ *
+ * Context: Any context. Takes and releases the xa_lock, interrupt-safe.
+ */
+void xa_destroy(struct xarray *xa)
+{
+ XA_STATE(xas, xa, 0);
+ unsigned long flags;
+ void *entry;
+
+ xas.xa_node = NULL;
+ xas_lock_irqsave(&xas, flags);
+ entry = xa_head_locked(xa);
+ RCU_INIT_POINTER(xa->xa_head, NULL);
+ xas_init_marks(&xas);
+ /* lockdep checks we're still holding the lock in xas_free_nodes() */
+ if (xa_is_node(entry))
+ xas_free_nodes(&xas, xa_to_node(entry));
+ xas_unlock_irqrestore(&xas, flags);
+}
+EXPORT_SYMBOL(xa_destroy);
+
#ifdef XA_DEBUG
void xa_dump_node(const struct xa_node *node)
{