diff options
Diffstat (limited to 'block/blk-ioc.c')
| -rw-r--r-- | block/blk-ioc.c | 130 |
1 files changed, 39 insertions, 91 deletions
diff --git a/block/blk-ioc.c b/block/blk-ioc.c index fb95dd2f889a..893b8007c657 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -155,20 +155,20 @@ void put_io_context(struct io_context *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; } @@ -197,6 +197,20 @@ retry: 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 @@ -218,19 +232,19 @@ void ioc_clear_queue(struct request_queue *q) } } -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); @@ -249,7 +263,12 @@ void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags, task->io_context = ioc; else kmem_cache_free(iocontext_cachep, ioc); + + ret = task->io_context ? 0 : -EBUSY; + task_unlock(task); + + return ret; } /** @@ -281,7 +300,7 @@ struct io_context *get_task_io_context(struct task_struct *task, return ioc; } task_unlock(task); - } while (create_io_context(task, gfp_flags, node)); + } while (!create_task_io_context(task, gfp_flags, node)); return NULL; } @@ -325,26 +344,23 @@ EXPORT_SYMBOL(ioc_lookup_icq); /** * 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) @@ -382,74 +398,6 @@ struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask) 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", |