[PATCH 2/2] blk-mq: add maps_tags fn and add usage

From: Matias Bjorling
Date: Mon Oct 28 2013 - 06:00:39 EST


Now that the tags mapping allows shared mapping, update blk-mq to allow
the driver to control initialization of the tags structure.

Signed-off-by: Matias Bjorling <m@xxxxxxxxxxx>
---
block/blk-mq.c | 19 +++++++++++--------
include/linux/blk-mq.h | 6 ++++++
2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f21ec96..ed94478 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1093,7 +1093,7 @@ static size_t order_to_size(unsigned int order)
}

static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
- unsigned int reserved_tags, int node)
+ struct blk_mq_reg *reg, int node)
{
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
@@ -1150,7 +1150,7 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
}
}

- if (i < (reserved_tags + BLK_MQ_TAG_MIN))
+ if (i < (reg->reserved_tags + BLK_MQ_TAG_MIN))
goto err_rq_map;
else if (i != hctx->queue_depth) {
hctx->queue_depth = i;
@@ -1158,14 +1158,17 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
__func__, i);
}

- hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
- if (!hctx->tags) {
+ if (reg->flags & ~(BLK_MQ_F_DRV_INIT_TAGS)) {
+ hctx->tags = blk_mq_init_tags(hctx->queue_depth,
+ reg->reserved_tags, node);
+ if (!hctx->tags)
+ goto err_rq_map;
+ }
+
+ return 0;
err_rq_map:
blk_mq_free_rq_map(hctx);
return -ENOMEM;
- }
-
- return 0;
}

static int blk_mq_init_hw_queues(struct request_queue *q,
@@ -1198,7 +1201,7 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
blk_mq_hctx_notify, hctx);
blk_mq_register_cpu_notifier(&hctx->cpu_notifier);

- if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node))
+ if (blk_mq_init_rq_map(hctx, reg, node))
break;

/*
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 746042ff..0b25075 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -107,6 +107,8 @@ enum {
BLK_MQ_F_SHOULD_SORT = 1 << 1,
BLK_MQ_F_SHOULD_IPI = 1 << 2,

+ BLK_MQ_F_DRV_INIT_TAGS = 1 << 3,
+
BLK_MQ_S_STOPPED = 1 << 0,

BLK_MQ_MAX_DEPTH = 2048,
@@ -138,6 +140,10 @@ void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_start_stopped_hw_queues(struct request_queue *q);

+struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
+ unsigned int reserved_tags, int node);
+void blk_mq_get_tags(struct blk_mq_tags *tags);
+
/*
* Driver command data is immediately after the request. So subtract request
* size to get back to the original request.
--
1.8.3.2

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