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UBI: Block: Add blk-mq support
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Convert the driver to blk-mq.
Beside of moving to the modern block interface this change boosts
also the performance of the driver.

nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xda
nand: Micron NAND 256MiB 3,3V 8-bit
nand: 256MiB, SLC, page size: 2048, OOB size: 64

root@debian-armhf:~# dd if=/dev/ubiblock0_0 of=/dev/zero bs=1M
243+1 records in
243+1 records out
255080448 bytes (255 MB) copied, 4.39295 s, 58.1 MB/s

vs.

root@debian-armhf:~# dd if=/dev/ubiblock0_0 of=/dev/zero bs=1M
243+1 records in
243+1 records out
255080448 bytes (255 MB) copied, 2.87676 s, 88.7 MB/s

Cc: hch@infradead.org
Cc: axboe@fb.com
Cc: tom.leiming@gmail.com
Signed-off-by: Richard Weinberger <richard@nod.at>
Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Reviewed-by: Jens Axboe <axboe@fb.com>
Acked-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
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Richard Weinberger committed Jan 28, 2015
1 parent 9ff0897 commit ff1f48e
Showing 1 changed file with 94 additions and 108 deletions.
202 changes: 94 additions & 108 deletions drivers/mtd/ubi/block.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,11 +42,12 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mtd/ubi.h>
#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/hdreg.h>
#include <linux/scatterlist.h>
#include <asm/div64.h>

#include "ubi-media.h"
Expand All @@ -67,6 +68,11 @@ struct ubiblock_param {
char name[UBIBLOCK_PARAM_LEN+1];
};

struct ubiblock_pdu {
struct work_struct work;
struct ubi_sgl usgl;
};

/* Numbers of elements set in the @ubiblock_param array */
static int ubiblock_devs __initdata;

Expand All @@ -84,11 +90,10 @@ struct ubiblock {
struct request_queue *rq;

struct workqueue_struct *wq;
struct work_struct work;

struct mutex dev_mutex;
spinlock_t queue_lock;
struct list_head list;
struct blk_mq_tag_set tag_set;
};

/* Linked list of all ubiblock instances */
Expand Down Expand Up @@ -181,31 +186,20 @@ static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
return NULL;
}

static int ubiblock_read_to_buf(struct ubiblock *dev, char *buffer,
int leb, int offset, int len)
static int ubiblock_read(struct ubiblock_pdu *pdu)
{
int ret;
int ret, leb, offset, bytes_left, to_read;
u64 pos;
struct request *req = blk_mq_rq_from_pdu(pdu);
struct ubiblock *dev = req->q->queuedata;

ret = ubi_read(dev->desc, leb, buffer, offset, len);
if (ret) {
dev_err(disk_to_dev(dev->gd), "%d while reading from LEB %d (offset %d, length %d)",
ret, leb, offset, len);
return ret;
}
return 0;
}

static int ubiblock_read(struct ubiblock *dev, char *buffer,
sector_t sec, int len)
{
int ret, leb, offset;
int bytes_left = len;
int to_read = len;
u64 pos = sec << 9;
to_read = blk_rq_bytes(req);
pos = blk_rq_pos(req) << 9;

/* Get LEB:offset address to read from */
offset = do_div(pos, dev->leb_size);
leb = pos;
bytes_left = to_read;

while (bytes_left) {
/*
Expand All @@ -215,11 +209,10 @@ static int ubiblock_read(struct ubiblock *dev, char *buffer,
if (offset + to_read > dev->leb_size)
to_read = dev->leb_size - offset;

ret = ubiblock_read_to_buf(dev, buffer, leb, offset, to_read);
if (ret)
ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
if (ret < 0)
return ret;

buffer += to_read;
bytes_left -= to_read;
to_read = bytes_left;
leb += 1;
Expand All @@ -228,79 +221,6 @@ static int ubiblock_read(struct ubiblock *dev, char *buffer,
return 0;
}

static int do_ubiblock_request(struct ubiblock *dev, struct request *req)
{
int len, ret;
sector_t sec;

if (req->cmd_type != REQ_TYPE_FS)
return -EIO;

if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
get_capacity(req->rq_disk))
return -EIO;

if (rq_data_dir(req) != READ)
return -ENOSYS; /* Write not implemented */

sec = blk_rq_pos(req);
len = blk_rq_cur_bytes(req);

/*
* Let's prevent the device from being removed while we're doing I/O
* work. Notice that this means we serialize all the I/O operations,
* but it's probably of no impact given the NAND core serializes
* flash access anyway.
*/
mutex_lock(&dev->dev_mutex);
ret = ubiblock_read(dev, bio_data(req->bio), sec, len);
mutex_unlock(&dev->dev_mutex);

return ret;
}

static void ubiblock_do_work(struct work_struct *work)
{
struct ubiblock *dev =
container_of(work, struct ubiblock, work);
struct request_queue *rq = dev->rq;
struct request *req;
int res;

spin_lock_irq(rq->queue_lock);

req = blk_fetch_request(rq);
while (req) {

spin_unlock_irq(rq->queue_lock);
res = do_ubiblock_request(dev, req);
spin_lock_irq(rq->queue_lock);

/*
* If we're done with this request,
* we need to fetch a new one
*/
if (!__blk_end_request_cur(req, res))
req = blk_fetch_request(rq);
}

spin_unlock_irq(rq->queue_lock);
}

static void ubiblock_request(struct request_queue *rq)
{
struct ubiblock *dev;
struct request *req;

dev = rq->queuedata;

if (!dev)
while ((req = blk_fetch_request(rq)) != NULL)
__blk_end_request_all(req, -ENODEV);
else
queue_work(dev->wq, &dev->work);
}

static int ubiblock_open(struct block_device *bdev, fmode_t mode)
{
struct ubiblock *dev = bdev->bd_disk->private_data;
Expand Down Expand Up @@ -374,6 +294,57 @@ static const struct block_device_operations ubiblock_ops = {
.getgeo = ubiblock_getgeo,
};

static void ubiblock_do_work(struct work_struct *work)
{
int ret;
struct ubiblock_pdu *pdu = container_of(work, struct ubiblock_pdu, work);
struct request *req = blk_mq_rq_from_pdu(pdu);

blk_mq_start_request(req);
blk_rq_map_sg(req->q, req, pdu->usgl.sg);

ret = ubiblock_read(pdu);
blk_mq_end_request(req, ret);
}

static int ubiblock_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct request *req = bd->rq;
struct ubiblock *dev = hctx->queue->queuedata;
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);

if (req->cmd_type != REQ_TYPE_FS)
return BLK_MQ_RQ_QUEUE_ERROR;

if (rq_data_dir(req) != READ)
return BLK_MQ_RQ_QUEUE_ERROR; /* Write not implemented */

ubi_sgl_init(&pdu->usgl);
queue_work(dev->wq, &pdu->work);

return BLK_MQ_RQ_QUEUE_OK;
}

static int ubiblock_init_request(void *data, struct request *req,
unsigned int hctx_idx,
unsigned int request_idx,
unsigned int numa_node)
{
struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);

sg_init_table(pdu->usgl.sg, UBI_MAX_SG_COUNT);
INIT_WORK(&pdu->work, ubiblock_do_work);

return 0;
}

static struct blk_mq_ops ubiblock_mq_ops = {
.queue_rq = ubiblock_queue_rq,
.init_request = ubiblock_init_request,
.map_queue = blk_mq_map_queue,
};

int ubiblock_create(struct ubi_volume_info *vi)
{
struct ubiblock *dev;
Expand Down Expand Up @@ -417,13 +388,27 @@ int ubiblock_create(struct ubi_volume_info *vi)
set_capacity(gd, disk_capacity);
dev->gd = gd;

spin_lock_init(&dev->queue_lock);
dev->rq = blk_init_queue(ubiblock_request, &dev->queue_lock);
dev->tag_set.ops = &ubiblock_mq_ops;
dev->tag_set.queue_depth = 64;
dev->tag_set.numa_node = NUMA_NO_NODE;
dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
dev->tag_set.driver_data = dev;
dev->tag_set.nr_hw_queues = 1;

ret = blk_mq_alloc_tag_set(&dev->tag_set);
if (ret) {
dev_err(disk_to_dev(dev->gd), "blk_mq_alloc_tag_set failed");
goto out_put_disk;
}

dev->rq = blk_mq_init_queue(&dev->tag_set);
if (!dev->rq) {
dev_err(disk_to_dev(gd), "blk_init_queue failed");
dev_err(disk_to_dev(gd), "blk_mq_init_queue failed");
ret = -ENODEV;
goto out_put_disk;
goto out_free_tags;
}
blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);

dev->rq->queuedata = dev;
dev->gd->queue = dev->rq;
Expand All @@ -437,7 +422,6 @@ int ubiblock_create(struct ubi_volume_info *vi)
ret = -ENOMEM;
goto out_free_queue;
}
INIT_WORK(&dev->work, ubiblock_do_work);

mutex_lock(&devices_mutex);
list_add_tail(&dev->list, &ubiblock_devices);
Expand All @@ -451,6 +435,8 @@ int ubiblock_create(struct ubi_volume_info *vi)

out_free_queue:
blk_cleanup_queue(dev->rq);
out_free_tags:
blk_mq_free_tag_set(&dev->tag_set);
out_put_disk:
put_disk(dev->gd);
out_free_dev:
Expand All @@ -461,8 +447,13 @@ int ubiblock_create(struct ubi_volume_info *vi)

static void ubiblock_cleanup(struct ubiblock *dev)
{
/* Stop new requests to arrive */
del_gendisk(dev->gd);
/* Flush pending work */
destroy_workqueue(dev->wq);
/* Finally destroy the blk queue */
blk_cleanup_queue(dev->rq);
blk_mq_free_tag_set(&dev->tag_set);
dev_info(disk_to_dev(dev->gd), "released");
put_disk(dev->gd);
}
Expand Down Expand Up @@ -490,9 +481,6 @@ int ubiblock_remove(struct ubi_volume_info *vi)
list_del(&dev->list);
mutex_unlock(&devices_mutex);

/* Flush pending work and stop this workqueue */
destroy_workqueue(dev->wq);

ubiblock_cleanup(dev);
mutex_unlock(&dev->dev_mutex);
kfree(dev);
Expand Down Expand Up @@ -620,8 +608,6 @@ static void ubiblock_remove_all(void)
struct ubiblock *dev;

list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
/* Flush pending work and stop workqueue */
destroy_workqueue(dev->wq);
/* The module is being forcefully removed */
WARN_ON(dev->desc);
/* Remove from device list */
Expand Down

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