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xarray: Destroy an XArray

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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>
This commit is contained in:
Matthew Wilcox 2017-11-17 08:16:34 -05:00
parent 80a0a1a9a3
commit 687149fca1
3 changed files with 63 additions and 0 deletions
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1
include/linux/xarray.h
View File

@ -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.

34
lib/test_xarray.c
View File

@ -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;

28
lib/xarray.c
View File

@ -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)
{