blk-ioc: Remove ioc's icq_list

Use the XArray's iterator instead of this hlist.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 1db53c371b1417cd2e93e4594b3c728429a71d1d..53da5bf9cdc21f5b17a946b43945ae4e69419801 100644 (file)
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -66,7 +66,6 @@ static void ioc_destroy_icq(struct io_cq *icq)
        lockdep_assert_held(&ioc->lock);
 
        xa_erase(&ioc->icq_array, icq->q->id);
-       hlist_del_init(&icq->ioc_node);
        list_del_init(&icq->q_node);
 
        /*
@@ -96,6 +95,8 @@ static void ioc_release_fn(struct work_struct *work)
        struct io_context *ioc = container_of(work, struct io_context,
                                              release_work);
        unsigned long flags;
+       unsigned long index;
+       struct io_cq *icq;
 
        /*
         * Exiting icq may call into put_io_context() through elevator
@@ -105,9 +106,7 @@ static void ioc_release_fn(struct work_struct *work)
         */
        spin_lock_irqsave_nested(&ioc->lock, flags, 1);
 
-       while (!hlist_empty(&ioc->icq_list)) {
-               struct io_cq *icq = hlist_entry(ioc->icq_list.first,
-                                               struct io_cq, ioc_node);
+       xa_for_each(&ioc->icq_array, index, icq) {
                struct request_queue *q = icq->q;
 
                if (spin_trylock(&q->queue_lock)) {
@@ -148,7 +147,7 @@ void put_io_context(struct io_context *ioc)
         */
        if (atomic_long_dec_and_test(&ioc->refcount)) {
                spin_lock_irqsave(&ioc->lock, flags);
-               if (!hlist_empty(&ioc->icq_list))
+               if (!xa_empty(&ioc->icq_array))
                        queue_work(system_power_efficient_wq,
                                        &ioc->release_work);
                else
@@ -170,6 +169,7 @@ void put_io_context(struct io_context *ioc)
 void put_io_context_active(struct io_context *ioc)
 {
        unsigned long flags;
+       unsigned long index;
        struct io_cq *icq;
 
        if (!atomic_dec_and_test(&ioc->active_ref)) {
@@ -183,7 +183,7 @@ void put_io_context_active(struct io_context *ioc)
         * explanation on the nested locking annotation.
         */
        spin_lock_irqsave_nested(&ioc->lock, flags, 1);
-       hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
+       xa_for_each(&ioc->icq_array, index, icq) {
                if (icq->flags & ICQ_EXITED)
                        continue;
 
@@ -256,7 +256,6 @@ int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
        atomic_set(&ioc->active_ref, 1);
        spin_lock_init(&ioc->lock);
        xa_init_flags(&ioc->icq_array, XA_FLAGS_LOCK_IRQ);
-       INIT_HLIST_HEAD(&ioc->icq_list);
        INIT_WORK(&ioc->release_work, ioc_release_fn);
 
        /*
@@ -386,7 +385,6 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
        icq->ioc = ioc;
        icq->q = q;
        INIT_LIST_HEAD(&icq->q_node);
-       INIT_HLIST_NODE(&icq->ioc_node);
 
        /* lock both q and ioc and try to link @icq */
        spin_lock_irq(&q->queue_lock);
@@ -395,7 +393,6 @@ struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
        curr = xa_cmpxchg(&ioc->icq_array, q->id, XA_ZERO_ENTRY, icq,
                        GFP_ATOMIC);
        if (likely(!curr)) {
-               hlist_add_head(&icq->ioc_node, &ioc->icq_list);
                list_add(&icq->q_node, &q->icq_list);
                if (et->ops.init_icq)
                        et->ops.init_icq(icq);

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index e16224f7008435144c40321f718034befb176d74..bc054ab9b27340e80ed0b231c87b8244007b7a1f 100644 (file)
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -53,8 +53,7 @@ enum {
  *
  * - ioc lock nests inside q lock.
  *
- * - ioc->icq_list and icq->ioc_node are protected by ioc lock.
- *   q->icq_list and icq->q_node by q lock.
+ * - q->icq_list and icq->q_node are protected by q lock.
  *
  * - 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
@@ -74,19 +73,15 @@ struct io_cq {
        struct io_context       *ioc;
 
        /*
-        * q_node and ioc_node link io_cq through icq_list of q and ioc
-        * respectively.  Both fields are unused once ioc_exit_icq() is
-        * called and shared with __rcu_icq_cache and __rcu_head which are
-        * used for RCU free of io_cq.
+        * q_node links io_cq through the icq_list of q.
+        * It is unused once ioc_exit_icq() is called so it is shared with
+        * __rcu_icq_cache which is used for RCU free of io_cq.
         */
        union {
                struct list_head        q_node;
                struct kmem_cache       *__rcu_icq_cache;
        };
-       union {
-               struct hlist_node       ioc_node;
-               struct rcu_head         __rcu_head;
-       };
+       struct rcu_head         __rcu_head;
 
        unsigned int            flags;
 };
@@ -113,7 +108,6 @@ struct io_context {
 
        struct xarray           icq_array;
        struct io_cq __rcu      *icq_hint;
-       struct hlist_head       icq_list;
 
        struct work_struct release_work;
 };