[PATCH 03/18] ioasid: Convert ioasid_idr to XArray

Jacob Pan
2019-04-08T23:59:18Z

IDR is to be replaced by XArray, keep up with the changes.
XArray has internal locking for normal APIs used here, also removed
radix tree related preload.

Suggested-by: Ira Weiny <ira.weiny-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Jacob Pan <jacob.jun.pan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
drivers/base/ioasid.c | 35 ++++++++++++++++-------------------
1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/base/ioasid.c b/drivers/base/ioasid.c
index 294e856..35bdc680 100644
--- a/drivers/base/ioasid.c
+++ b/drivers/base/ioasid.c
@@ -4,7 +4,7 @@
* subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
* free IOASIDs with ioasid_alloc and ioasid_free.
*/
-#include <linux/idr.h>
+#include <linux/xarray.h>
#include <linux/ioasid.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@@ -16,7 +16,7 @@ struct ioasid_data {
struct rcu_head rcu;
};

-static DEFINE_IDR(ioasid_idr);
+static DEFINE_XARRAY_ALLOC(ioasid_xa);
static DEFINE_MUTEX(ioasid_allocator_lock);
static const struct ioasid_allocator *ioasid_allocator;

@@ -24,9 +24,9 @@ static const struct ioasid_allocator *ioasid_allocator;
/**
* ioasid_set_allocator - register a custom allocator
*
- * Custom allocator take precedence over the default IDR based allocator.
+ * Custom allocator take precedence over the default xarray based allocator.
* Private data associated with the ASID are managed by ASID common code
- * similar to IDR data.
+ * similar to data stored in xa.
*/
int ioasid_set_allocator(struct ioasid_allocator *allocator)
{
@@ -72,13 +72,12 @@ int ioasid_set_data(ioasid_t ioasid, void *data)
struct ioasid_data *ioasid_data;
int ret = 0;

- idr_lock(&ioasid_idr);
- ioasid_data = idr_find(&ioasid_idr, ioasid);
+ ioasid_data = xa_load(&ioasid_xa, ioasid);
if (ioasid_data)
ioasid_data->private = data;
else
ret = -ENOENT;
- idr_unlock(&ioasid_idr);
+
/* getter may use the private data */
synchronize_rcu();

@@ -110,7 +109,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
data->set = set;
data->private = private;

- /* Use custom allocator if available, otherwise default to IDR */
+ /* Use custom allocator if available, otherwise default to xarray */
if (ioasid_allocator) {
mutex_lock(&ioasid_allocator_lock);
id = ioasid_allocator->alloc(min, max, ioasid_allocator->pdata);
@@ -120,17 +119,18 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
goto exit_free;
}
/*
- * Use IDR to manage private data also sanitiy check custom
+ * Use XA to manage private data also sanitiy check custom
* allocator for duplicates.
*/
min = id;
max = id + 1;
}
- idr_preload(GFP_KERNEL);
- idr_lock(&ioasid_idr);
- data->id = id = idr_alloc(&ioasid_idr, data, min, max, GFP_ATOMIC);
- idr_unlock(&ioasid_idr);
- idr_preload_end();
+
+ if (xa_alloc(&ioasid_xa, &id, data, XA_LIMIT(min, max), GFP_KERNEL)) {
+ pr_err("Failed to alloc ioasid from %d to %d\n", min, max);
+ goto exit_free;
+ }
+ data->id = id;

exit_free:
if (id < 0 || id == INVALID_IOASID) {
@@ -160,10 +160,7 @@ int ioasid_free(ioasid_t ioasid)
return ret;
}

- idr_lock(&ioasid_idr);
- ioasid_data = idr_remove(&ioasid_idr, ioasid);
- idr_unlock(&ioasid_idr);
-
+ ioasid_data = xa_erase(&ioasid_xa, ioasid);
if (ioasid_data)
kfree_rcu(ioasid_data, rcu);

@@ -192,7 +189,7 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
struct ioasid_data *ioasid_data;

rcu_read_lock();
- ioasid_data = idr_find(&ioasid_idr, ioasid);
+ ioasid_data = xa_load(&ioasid_xa, ioasid);
if (!ioasid_data) {
priv = ERR_PTR(-ENOENT);
goto unlock;
--
2.7.4