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Subject[PATCH v6 80/99] blk-ioc: Convert to XArray
Date
From: Matthew Wilcox <mawilcox@microsoft.com>

Skip converting the lock to use xa_lock; I think this code can live with
the double-locking.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
block/blk-ioc.c | 13 +++++++------
include/linux/iocontext.h | 6 +++---
2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index f23311e4b201..baf83c8ac503 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -68,7 +68,7 @@ static void ioc_destroy_icq(struct io_cq *icq)

lockdep_assert_held(&ioc->lock);

- radix_tree_delete(&ioc->icq_tree, icq->q->id);
+ xa_erase(&ioc->icq_array, icq->q->id);
hlist_del_init(&icq->ioc_node);
list_del_init(&icq->q_node);

@@ -278,7 +278,7 @@ int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
atomic_set(&ioc->nr_tasks, 1);
atomic_set(&ioc->active_ref, 1);
spin_lock_init(&ioc->lock);
- INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
+ xa_init_flags(&ioc->icq_array, XA_FLAGS_LOCK_IRQ);
INIT_HLIST_HEAD(&ioc->icq_list);
INIT_WORK(&ioc->release_work, ioc_release_fn);

@@ -363,7 +363,7 @@ struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q)
if (icq && icq->q == q)
goto out;

- icq = radix_tree_lookup(&ioc->icq_tree, q->id);
+ icq = xa_load(&ioc->icq_array, q->id);
if (icq && icq->q == q)
rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
else
@@ -398,7 +398,7 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
if (!icq)
return NULL;

- if (radix_tree_maybe_preload(gfp_mask) < 0) {
+ if (xa_reserve(&ioc->icq_array, q->id, gfp_mask)) {
kmem_cache_free(et->icq_cache, icq);
return NULL;
}
@@ -412,7 +412,8 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
spin_lock_irq(q->queue_lock);
spin_lock(&ioc->lock);

- if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
+ if (likely(!xa_store(&ioc->icq_array, q->id, icq,
+ GFP_ATOMIC | __GFP_HIGH))) {
hlist_add_head(&icq->ioc_node, &ioc->icq_list);
list_add(&icq->q_node, &q->icq_list);
if (et->uses_mq && et->ops.mq.init_icq)
@@ -421,6 +422,7 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
et->ops.sq.elevator_init_icq_fn(icq);
} else {
kmem_cache_free(et->icq_cache, icq);
+ xa_erase(&ioc->icq_array, q->id);
icq = ioc_lookup_icq(ioc, q);
if (!icq)
printk(KERN_ERR "cfq: icq link failed!\n");
@@ -428,7 +430,6 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,

spin_unlock(&ioc->lock);
spin_unlock_irq(q->queue_lock);
- radix_tree_preload_end();
return icq;
}

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index dba15ca8e60b..e16224f70084 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -2,9 +2,9 @@
#ifndef IOCONTEXT_H
#define IOCONTEXT_H

-#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
+#include <linux/xarray.h>

enum {
ICQ_EXITED = 1 << 2,
@@ -56,7 +56,7 @@ enum {
* - ioc->icq_list and icq->ioc_node are protected by ioc lock.
* q->icq_list and icq->q_node by q lock.
*
- * - ioc->icq_tree and ioc->icq_hint are protected by ioc lock, while icq
+ * - ioc->icq_array and ioc->icq_hint are protected by ioc lock, while icq
* itself is protected by q lock. However, both the indexes and icq
* itself are also RCU managed and lookup can be performed holding only
* the q lock.
@@ -111,7 +111,7 @@ struct io_context {
int nr_batch_requests; /* Number of requests left in the batch */
unsigned long last_waited; /* Time last woken after wait for request */

- struct radix_tree_root icq_tree;
+ struct xarray icq_array;
struct io_cq __rcu *icq_hint;
struct hlist_head icq_list;

--
2.15.1
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