Re: [PATCH 4/4] blk-mq: add a exit_request method

From: Christoph Hellwig
Date: Wed Mar 19 2014 - 03:57:11 EST


On Wed, Mar 19, 2014 at 01:22:07PM +0800, Ming Lei wrote:
> exit_request definition is missed.

oops that accidentally went into another commit.

New version below:

---
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Subject: blk-mq: add a exit_request method

This gives drivers an easy way to free any ressources allocated in
->init_request.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c2ce99b..c7e723e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1000,6 +1000,16 @@ static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
{
struct page *page;

+ if (hctx->rqs && hctx->queue->mq_ops->exit_request) {
+ int i;
+
+ for (i = 0; i < hctx->queue_depth; i++) {
+ if (!hctx->rqs[i])
+ continue;
+ hctx->queue->mq_ops->exit_request(hctx, hctx->rqs[i]);
+ }
+ }
+
while (!list_empty(&hctx->page_list)) {
page = list_first_entry(&hctx->page_list, struct page, lru);
list_del_init(&page->lru);
@@ -1332,7 +1342,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,
}

if (blk_mq_init_hw_queues(q, reg, driver_data))
- goto err_flush_rq;
+ goto err_flush_rq_init;

blk_mq_map_swqueue(q);

@@ -1342,6 +1352,9 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,

return q;

+err_flush_rq_init:
+ if (reg->ops->exit_request)
+ reg->ops->exit_request(NULL, q->flush_rq);
err_flush_rq:
kfree(q->flush_rq);
err_hw:
@@ -1387,6 +1400,9 @@ void blk_mq_free_queue(struct request_queue *q)
mutex_lock(&all_q_mutex);
list_del_init(&q->all_q_node);
mutex_unlock(&all_q_mutex);
+
+ if (q->mq_ops->exit_request)
+ q->mq_ops->exit_request(NULL, q->flush_rq);
}

/* Basically redo blk_mq_init_queue with queue frozen */
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 4d34957..ff194f8 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -68,6 +68,7 @@ typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
typedef int (init_request_fn)(void *, struct blk_mq_hw_ctx *,
struct request *, unsigned int);
+typedef void (exit_request_fn)(struct blk_mq_hw_ctx *, struct request *);

struct blk_mq_ops {
/*
@@ -104,8 +105,10 @@ struct blk_mq_ops {
/*
* Called for every command allocated by the block layer to allow
* the driver to set up driver specific data.
+ * Ditto for exit/teardown.
*/
init_request_fn *init_request;
+ exit_request_fn *exit_request;
};

enum {
--
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