[PATCH 3/3] blk-mq: add ->init_request and ->exit_request methods
From: Christoph Hellwig
Date: Fri Mar 21 2014 - 12:53:00 EST
Besides a simpler and cleared interface this also allows to initialize the
flush_rq properly. The interface for that is still a bit messy as we don't
have a hw_ctx available for the flush request, but that's something that
should be fixable with a little work once the demand arises.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 119 +++++++++++++++++---------------------------
drivers/block/virtio_blk.c | 23 ++++-----
include/linux/blk-mq.h | 16 +++++-
3 files changed, 72 insertions(+), 86 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4274ee0..762095f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -996,75 +996,20 @@ static void blk_mq_hctx_notify(void *data, unsigned long action,
blk_mq_put_ctx(ctx);
}
-static int blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
- int (*init)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
+static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
{
- unsigned int i;
- int ret = 0;
-
- for (i = 0; i < hctx->queue_depth; i++) {
- struct request *rq = hctx->rqs[i];
-
- ret = init(data, hctx, rq, i);
- if (ret)
- break;
- }
-
- return ret;
-}
+ struct page *page;
-int blk_mq_init_commands(struct request_queue *q,
- int (*init)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
-{
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
- int ret = 0;
+ if (hctx->rqs && hctx->queue->mq_ops->exit_request) {
+ int i;
- queue_for_each_hw_ctx(q, hctx, i) {
- ret = blk_mq_init_hw_commands(hctx, init, data);
- if (ret)
- break;
+ for (i = 0; i < hctx->queue_depth; i++) {
+ if (!hctx->rqs[i])
+ continue;
+ hctx->queue->mq_ops->exit_request(hctx, hctx->rqs[i]);
+ }
}
- return ret;
-}
-EXPORT_SYMBOL(blk_mq_init_commands);
-
-static void blk_mq_free_hw_commands(struct blk_mq_hw_ctx *hctx,
- void (*free)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
-{
- unsigned int i;
-
- for (i = 0; i < hctx->queue_depth; i++) {
- struct request *rq = hctx->rqs[i];
-
- free(data, hctx, rq, i);
- }
-}
-
-void blk_mq_free_commands(struct request_queue *q,
- void (*free)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
-{
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
-
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_free_hw_commands(hctx, free, data);
-}
-EXPORT_SYMBOL(blk_mq_free_commands);
-
-static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
-{
- struct page *page;
-
while (!list_empty(&hctx->page_list)) {
page = list_first_entry(&hctx->page_list, struct page, lru);
list_del_init(&page->lru);
@@ -1088,10 +1033,12 @@ 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, void *driver_data, int node)
{
+ unsigned int reserved_tags = reg->reserved_tags;
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
+ int error;
INIT_LIST_HEAD(&hctx->page_list);
@@ -1140,14 +1087,23 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
for (j = 0; j < to_do; j++) {
hctx->rqs[i] = p;
blk_mq_rq_init(hctx, hctx->rqs[i]);
+ if (reg->ops->init_request) {
+ error = reg->ops->init_request(driver_data,
+ hctx, hctx->rqs[i], i);
+ if (error)
+ goto err_rq_map;
+ }
+
p += rq_size;
i++;
}
}
- if (i < (reserved_tags + BLK_MQ_TAG_MIN))
+ if (i < (reserved_tags + BLK_MQ_TAG_MIN)) {
+ error = -ENOMEM;
goto err_rq_map;
- else if (i != hctx->queue_depth) {
+ }
+ if (i != hctx->queue_depth) {
hctx->queue_depth = i;
pr_warn("%s: queue depth set to %u because of low memory\n",
__func__, i);
@@ -1155,12 +1111,14 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
if (!hctx->tags) {
-err_rq_map:
- blk_mq_free_rq_map(hctx);
- return -ENOMEM;
+ error = -ENOMEM;
+ goto err_rq_map;
}
return 0;
+err_rq_map:
+ blk_mq_free_rq_map(hctx);
+ return error;
}
static int blk_mq_init_hw_queues(struct request_queue *q,
@@ -1193,7 +1151,7 @@ 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, driver_data, node))
break;
/*
@@ -1372,8 +1330,19 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,
if (!q->flush_rq)
goto err_hw;
+ if (reg->ops->init_request) {
+ blk_rq_init(q, q->flush_rq);
+ if (reg->cmd_size)
+ q->flush_rq->special =
+ blk_mq_rq_to_pdu(q->flush_rq);
+
+ if (reg->ops->init_request(driver_data,
+ NULL, q->flush_rq, -1))
+ goto err_flush_rq;
+ }
+
if (blk_mq_init_hw_queues(q, reg, driver_data))
- goto err_flush_rq;
+ goto err_flush_rq_init;
blk_mq_map_swqueue(q);
@@ -1383,6 +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:
@@ -1428,6 +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/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0eace43..a2e925b 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -474,11 +474,22 @@ static const struct device_attribute dev_attr_cache_type_rw =
__ATTR(cache_type, S_IRUGO|S_IWUSR,
virtblk_cache_type_show, virtblk_cache_type_store);
+static int virtblk_init_request(void *data, struct blk_mq_hw_ctx *hctx,
+ struct request *rq, unsigned int nr)
+{
+ struct virtio_blk *vblk = data;
+ struct virtblk_req *vbr = rq->special;
+
+ sg_init_table(vbr->sg, vblk->sg_elems);
+ return 0;
+}
+
static struct blk_mq_ops virtio_mq_ops = {
.queue_rq = virtio_queue_rq,
.map_queue = blk_mq_map_queue,
.alloc_hctx = blk_mq_alloc_single_hw_queue,
.free_hctx = blk_mq_free_single_hw_queue,
+ .init_request = virtblk_init_request,
.complete = virtblk_request_done,
};
@@ -490,16 +501,6 @@ static struct blk_mq_reg virtio_mq_reg = {
.flags = BLK_MQ_F_SHOULD_MERGE,
};
-static int virtblk_init_vbr(void *data, struct blk_mq_hw_ctx *hctx,
- struct request *rq, unsigned int nr)
-{
- struct virtio_blk *vblk = data;
- struct virtblk_req *vbr = rq->special;
-
- sg_init_table(vbr->sg, vblk->sg_elems);
- return 0;
-}
-
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
@@ -563,8 +564,6 @@ static int virtblk_probe(struct virtio_device *vdev)
goto out_put_disk;
}
- blk_mq_init_commands(q, virtblk_init_vbr, vblk);
-
q->queuedata = vblk;
virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 0120451..e8e81c5 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -66,6 +66,9 @@ typedef struct blk_mq_hw_ctx *(alloc_hctx_fn)(struct blk_mq_reg *,unsigned int);
typedef void (free_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
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 {
/*
@@ -98,6 +101,17 @@ struct blk_mq_ops {
*/
init_hctx_fn *init_hctx;
exit_hctx_fn *exit_hctx;
+
+ /*
+ * Called for every command allocated by the block layer to allow
+ * the driver to set up driver specific data.
+ * Ditto for exit/teardown.
+ *
+ * Note that the hctx argument might be NULL for the flush request
+ * for either call.
+ */
+ init_request_fn *init_request;
+ exit_request_fn *exit_request;
};
enum {
@@ -117,8 +131,6 @@ enum {
struct request_queue *blk_mq_init_queue(struct blk_mq_reg *, void *);
int blk_mq_register_disk(struct gendisk *);
void blk_mq_unregister_disk(struct gendisk *);
-int blk_mq_init_commands(struct request_queue *, int (*init)(void *data, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data);
-void blk_mq_free_commands(struct request_queue *, void (*free)(void *data, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data);
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
--
1.7.10.4
--
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