[PATCH v5 01/10] blk-mq: handle failure path for initializing hctx

Ming Lei
2014-09-25T15:26:50Z

Failure of initializing one hctx isn't handled, so this patch
introduces blk_mq_init_hctx() and its pair to handle it explicitly.
Also this patch makes code cleaner.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
block/blk-mq.c | 114 ++++++++++++++++++++++++++++++++++----------------------
1 file changed, 69 insertions(+), 45 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 03f5c79..d8c7f90 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1509,6 +1509,20 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
return NOTIFY_OK;
}

+static void blk_mq_exit_hctx(struct request_queue *q,
+ struct blk_mq_tag_set *set,
+ struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
+{
+ blk_mq_tag_idle(hctx);
+
+ if (set->ops->exit_hctx)
+ set->ops->exit_hctx(hctx, hctx_idx);
+
+ blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
+ kfree(hctx->ctxs);
+ blk_mq_free_bitmap(&hctx->ctx_map);
+}
+
static void blk_mq_exit_hw_queues(struct request_queue *q,
struct blk_mq_tag_set *set, int nr_queue)
{
@@ -1518,17 +1532,8 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
queue_for_each_hw_ctx(q, hctx, i) {
if (i == nr_queue)
break;
-
- blk_mq_tag_idle(hctx);
-
- if (set->ops->exit_hctx)
- set->ops->exit_hctx(hctx, i);
-
- blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
- kfree(hctx->ctxs);
- blk_mq_free_bitmap(&hctx->ctx_map);
+ blk_mq_exit_hctx(q, set, hctx, i);
}
-
}

static void blk_mq_free_hw_queues(struct request_queue *q,
@@ -1543,53 +1548,72 @@ static void blk_mq_free_hw_queues(struct request_queue *q,
}
}

-static int blk_mq_init_hw_queues(struct request_queue *q,
- struct blk_mq_tag_set *set)
+static int blk_mq_init_hctx(struct request_queue *q,
+ struct blk_mq_tag_set *set,
+ struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
{
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
+ int node;
+
+ node = hctx->numa_node;
+ if (node == NUMA_NO_NODE)
+ node = hctx->numa_node = set->numa_node;
+
+ INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
+ INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
+ spin_lock_init(&hctx->lock);
+ INIT_LIST_HEAD(&hctx->dispatch);
+ hctx->queue = q;
+ hctx->queue_num = hctx_idx;
+ hctx->flags = set->flags;
+ hctx->cmd_size = set->cmd_size;
+
+ blk_mq_init_cpu_notifier(&hctx->cpu_notifier,
+ blk_mq_hctx_notify, hctx);
+ blk_mq_register_cpu_notifier(&hctx->cpu_notifier);
+
+ hctx->tags = set->tags[hctx_idx];

/*
- * Initialize hardware queues
+ * Allocate space for all possible cpus to avoid allocation at
+ * runtime
*/
- queue_for_each_hw_ctx(q, hctx, i) {
- int node;
+ hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
+ GFP_KERNEL, node);
+ if (!hctx->ctxs)
+ goto unregister_cpu_notifier;

- node = hctx->numa_node;
- if (node == NUMA_NO_NODE)
- node = hctx->numa_node = set->numa_node;
+ if (blk_mq_alloc_bitmap(&hctx->ctx_map, node))
+ goto free_ctxs;

- INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
- INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
- spin_lock_init(&hctx->lock);
- INIT_LIST_HEAD(&hctx->dispatch);
- hctx->queue = q;
- hctx->queue_num = i;
- hctx->flags = set->flags;
- hctx->cmd_size = set->cmd_size;
+ hctx->nr_ctx = 0;

- blk_mq_init_cpu_notifier(&hctx->cpu_notifier,
- blk_mq_hctx_notify, hctx);
- blk_mq_register_cpu_notifier(&hctx->cpu_notifier);
+ if (set->ops->init_hctx &&
+ set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
+ goto free_bitmap;

- hctx->tags = set->tags[i];
+ return 0;

- /*
- * Allocate space for all possible cpus to avoid allocation at
- * runtime
- */
- hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
- GFP_KERNEL, node);
- if (!hctx->ctxs)
- break;
+ free_bitmap:
+ blk_mq_free_bitmap(&hctx->ctx_map);
+ free_ctxs:
+ kfree(hctx->ctxs);
+ unregister_cpu_notifier:
+ blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);

- if (blk_mq_alloc_bitmap(&hctx->ctx_map, node))
- break;
+ return -1;
+}

- hctx->nr_ctx = 0;
+static int blk_mq_init_hw_queues(struct request_queue *q,
+ struct blk_mq_tag_set *set)
+{
+ struct blk_mq_hw_ctx *hctx;
+ unsigned int i;

- if (set->ops->init_hctx &&
- set->ops->init_hctx(hctx, set->driver_data, i))
+ /*
+ * Initialize hardware queues
+ */
+ queue_for_each_hw_ctx(q, hctx, i) {
+ if (blk_mq_init_hctx(q, set, hctx, i))
break;
}

--
1.7.9.5