[PATCH] ubi: block: set BLK_MQ_F_BLOCKING
Christoph Hellwig
hch at lst.de
Thu Jan 12 08:15:40 PST 2023
Set BLK_MQ_F_BLOCKING so that the block layer always calls ->queue_rq
from process context and drop the driver internal workqueue.
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
drivers/mtd/ubi/block.c | 97 ++++++++++++-----------------------------
1 file changed, 28 insertions(+), 69 deletions(-)
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 75eaecc8639f00..1f163c443f3049 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -35,7 +35,6 @@
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/mtd/ubi.h>
-#include <linux/workqueue.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/hdreg.h>
@@ -62,7 +61,6 @@ struct ubiblock_param {
};
struct ubiblock_pdu {
- struct work_struct work;
struct ubi_sgl usgl;
};
@@ -82,8 +80,6 @@ struct ubiblock {
struct gendisk *gd;
struct request_queue *rq;
- struct workqueue_struct *wq;
-
struct mutex dev_mutex;
struct list_head list;
struct blk_mq_tag_set tag_set;
@@ -181,20 +177,29 @@ static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
return NULL;
}
-static int ubiblock_read(struct ubiblock_pdu *pdu)
+static blk_status_t ubiblock_read(struct request *req)
{
- int ret, leb, offset, bytes_left, to_read;
- u64 pos;
- struct request *req = blk_mq_rq_from_pdu(pdu);
+ struct ubiblock_pdu *pdu = blk_mq_rq_to_pdu(req);
struct ubiblock *dev = req->q->queuedata;
+ u64 pos = blk_rq_pos(req) << 9;
+ int to_read = blk_rq_bytes(req);
+ int bytes_left = to_read;
+ /* Get LEB:offset address to read from */
+ int offset = do_div(pos, dev->leb_size);
+ int leb = pos;
+ struct req_iterator iter;
+ struct bio_vec bvec;
+ int ret;
- to_read = blk_rq_bytes(req);
- pos = blk_rq_pos(req) << 9;
+ blk_mq_start_request(req);
- /* Get LEB:offset address to read from */
- offset = do_div(pos, dev->leb_size);
- leb = pos;
- bytes_left = to_read;
+ /*
+ * It is safe to ignore the return value of blk_rq_map_sg() because
+ * the number of sg entries is limited to UBI_MAX_SG_COUNT
+ * and ubi_read_sg() will check that limit.
+ */
+ ubi_sgl_init(&pdu->usgl);
+ blk_rq_map_sg(req->q, req, pdu->usgl.sg);
while (bytes_left) {
/*
@@ -206,14 +211,17 @@ static int ubiblock_read(struct ubiblock_pdu *pdu)
ret = ubi_read_sg(dev->desc, leb, &pdu->usgl, offset, to_read);
if (ret < 0)
- return ret;
+ break;
bytes_left -= to_read;
to_read = bytes_left;
leb += 1;
offset = 0;
}
- return 0;
+
+ rq_for_each_segment(bvec, req, iter)
+ flush_dcache_page(bvec.bv_page);
+ return errno_to_blk_status(ret);
}
static int ubiblock_open(struct block_device *bdev, fmode_t mode)
@@ -289,47 +297,15 @@ 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);
- struct req_iterator iter;
- struct bio_vec bvec;
-
- blk_mq_start_request(req);
-
- /*
- * It is safe to ignore the return value of blk_rq_map_sg() because
- * the number of sg entries is limited to UBI_MAX_SG_COUNT
- * and ubi_read_sg() will check that limit.
- */
- blk_rq_map_sg(req->q, req, pdu->usgl.sg);
-
- ret = ubiblock_read(pdu);
-
- rq_for_each_segment(bvec, req, iter)
- flush_dcache_page(bvec.bv_page);
-
- blk_mq_end_request(req, errno_to_blk_status(ret));
-}
-
static blk_status_t 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);
-
- switch (req_op(req)) {
+ switch (req_op(bd->rq)) {
case REQ_OP_READ:
- ubi_sgl_init(&pdu->usgl);
- queue_work(dev->wq, &pdu->work);
- return BLK_STS_OK;
+ return ubiblock_read(bd->rq);
default:
return BLK_STS_IOERR;
}
-
}
static int ubiblock_init_request(struct blk_mq_tag_set *set,
@@ -339,8 +315,6 @@ static int ubiblock_init_request(struct blk_mq_tag_set *set,
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;
}
@@ -401,7 +375,7 @@ int ubiblock_create(struct ubi_volume_info *vi)
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.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_BLOCKING;
dev->tag_set.cmd_size = sizeof(struct ubiblock_pdu);
dev->tag_set.driver_data = dev;
dev->tag_set.nr_hw_queues = 1;
@@ -439,31 +413,18 @@ int ubiblock_create(struct ubi_volume_info *vi)
dev->rq = gd->queue;
blk_queue_max_segments(dev->rq, UBI_MAX_SG_COUNT);
- /*
- * Create one workqueue per volume (per registered block device).
- * Remember workqueues are cheap, they're not threads.
- */
- dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
- if (!dev->wq) {
- ret = -ENOMEM;
- goto out_remove_minor;
- }
-
list_add_tail(&dev->list, &ubiblock_devices);
/* Must be the last step: anyone can call file ops from now on */
ret = add_disk(dev->gd);
if (ret)
- goto out_destroy_wq;
+ goto out_remove_minor;
dev_info(disk_to_dev(dev->gd), "created from ubi%d:%d(%s)",
dev->ubi_num, dev->vol_id, vi->name);
mutex_unlock(&devices_mutex);
return 0;
-out_destroy_wq:
- list_del(&dev->list);
- destroy_workqueue(dev->wq);
out_remove_minor:
idr_remove(&ubiblock_minor_idr, gd->first_minor);
out_cleanup_disk:
@@ -482,8 +443,6 @@ 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 */
dev_info(disk_to_dev(dev->gd), "released");
put_disk(dev->gd);
--
2.39.0
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