void put_io_context(struct io_context *ioc)
{
unsigned long flags;
+ bool free_ioc = false;
if (ioc == NULL)
return;
spin_lock_irqsave(&ioc->lock, flags);
if (!hlist_empty(&ioc->icq_list))
schedule_work(&ioc->release_work);
+ else
+ free_ioc = true;
spin_unlock_irqrestore(&ioc->lock, flags);
}
+
+ if (free_ioc)
+ kmem_cache_free(iocontext_cachep, ioc);
}
EXPORT_SYMBOL(put_io_context);
-/* Called by the exiting task */
-void exit_io_context(struct task_struct *task)
+/**
+ * put_io_context_active - put active reference on ioc
+ * @ioc: ioc of interest
+ *
+ * Undo get_io_context_active(). If active reference reaches zero after
+ * put, @ioc can never issue further IOs and ioscheds are notified.
+ */
+void put_io_context_active(struct io_context *ioc)
{
- struct io_context *ioc;
- struct io_cq *icq;
struct hlist_node *n;
unsigned long flags;
+ struct io_cq *icq;
- task_lock(task);
- ioc = task->io_context;
- task->io_context = NULL;
- task_unlock(task);
-
- if (!atomic_dec_and_test(&ioc->nr_tasks)) {
+ if (!atomic_dec_and_test(&ioc->active_ref)) {
put_io_context(ioc);
return;
}
put_io_context(ioc);
}
+/* Called by the exiting task */
+void exit_io_context(struct task_struct *task)
+{
+ struct io_context *ioc;
+
+ task_lock(task);
+ ioc = task->io_context;
+ task->io_context = NULL;
+ task_unlock(task);
+
+ atomic_dec(&ioc->nr_tasks);
+ put_io_context_active(ioc);
+}
+
/**
* ioc_clear_queue - break any ioc association with the specified queue
* @q: request_queue being cleared
}
}
-void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
- int node)
+int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
{
struct io_context *ioc;
+ int ret;
ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
node);
if (unlikely(!ioc))
- return;
+ return -ENOMEM;
/* initialize */
atomic_long_set(&ioc->refcount, 1);
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);
INIT_HLIST_HEAD(&ioc->icq_list);
task->io_context = ioc;
else
kmem_cache_free(iocontext_cachep, ioc);
+
+ ret = task->io_context ? 0 : -EBUSY;
+
task_unlock(task);
+
+ return ret;
}
/**
return ioc;
}
task_unlock(task);
- } while (create_io_context(task, gfp_flags, node));
+ } while (!create_task_io_context(task, gfp_flags, node));
return NULL;
}
/**
* ioc_create_icq - create and link io_cq
+ * @ioc: io_context of interest
* @q: request_queue of interest
* @gfp_mask: allocation mask
*
- * Make sure io_cq linking %current->io_context and @q exists. If either
- * io_context and/or icq don't exist, they will be created using @gfp_mask.
+ * Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they
+ * will be created using @gfp_mask.
*
* The caller is responsible for ensuring @ioc won't go away and @q is
* alive and will stay alive until this function returns.
*/
-struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
+struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
+ gfp_t gfp_mask)
{
struct elevator_type *et = q->elevator->type;
- struct io_context *ioc;
struct io_cq *icq;
/* allocate stuff */
- ioc = create_io_context(current, gfp_mask, q->node);
- if (!ioc)
- return NULL;
-
icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
q->node);
if (!icq)
return icq;
}
-void ioc_set_icq_flags(struct io_context *ioc, unsigned int flags)
-{
- struct io_cq *icq;
- struct hlist_node *n;
-
- hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
- icq->flags |= flags;
-}
-
-/**
- * ioc_ioprio_changed - notify ioprio change
- * @ioc: io_context of interest
- * @ioprio: new ioprio
- *
- * @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
- * icq's. iosched is responsible for checking the bit and applying it on
- * request issue path.
- */
-void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&ioc->lock, flags);
- ioc->ioprio = ioprio;
- ioc_set_icq_flags(ioc, ICQ_IOPRIO_CHANGED);
- spin_unlock_irqrestore(&ioc->lock, flags);
-}
-
-/**
- * ioc_cgroup_changed - notify cgroup change
- * @ioc: io_context of interest
- *
- * @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
- * iosched is responsible for checking the bit and applying it on request
- * issue path.
- */
-void ioc_cgroup_changed(struct io_context *ioc)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&ioc->lock, flags);
- ioc_set_icq_flags(ioc, ICQ_CGROUP_CHANGED);
- spin_unlock_irqrestore(&ioc->lock, flags);
-}
-EXPORT_SYMBOL(ioc_cgroup_changed);
-
-/**
- * icq_get_changed - fetch and clear icq changed mask
- * @icq: icq of interest
- *
- * Fetch and clear ICQ_*_CHANGED bits from @icq. Grabs and releases
- * @icq->ioc->lock.
- */
-unsigned icq_get_changed(struct io_cq *icq)
-{
- unsigned int changed = 0;
- unsigned long flags;
-
- if (unlikely(icq->flags & ICQ_CHANGED_MASK)) {
- spin_lock_irqsave(&icq->ioc->lock, flags);
- changed = icq->flags & ICQ_CHANGED_MASK;
- icq->flags &= ~ICQ_CHANGED_MASK;
- spin_unlock_irqrestore(&icq->ioc->lock, flags);
- }
- return changed;
-}
-EXPORT_SYMBOL(icq_get_changed);
-
static int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",
Code Review / linux-3.10.git / blobdiff