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Subject[PATCH v9 20/61] xarray: Add xa_destroy
Date
From: Matthew Wilcox <mawilcox@microsoft.com>

This function frees all the internal memory allocated to the xarray
and reinitialises it to be empty.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
include/linux/xarray.h | 1 +
lib/xarray.c | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+)

diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 85dd909586f0..96773f83ae03 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -229,6 +229,7 @@ void *xa_find_after(struct xarray *xa, unsigned long *index,
unsigned long max, xa_tag_t) __attribute__((nonnull(2)));
unsigned int xa_extract(struct xarray *, void **dst, unsigned long start,
unsigned long max, unsigned int n, xa_tag_t);
+void xa_destroy(struct xarray *);

/**
* xa_init() - Initialise an empty XArray.
diff --git a/lib/xarray.c b/lib/xarray.c
index 124bbfec66ae..080ed0fc3feb 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1468,6 +1468,34 @@ 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_tags(&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)
{
--
2.16.1
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