[PATCH 2/2] ubd: use blk_mq_alloc_disk and blk_cleanup_disk

From: Christoph Hellwig
Date: Mon Jun 14 2021 - 02:08:32 EST


Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/um/drivers/ubd_kern.c | 44 ++++++++++++--------------------------
1 file changed, 14 insertions(+), 30 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index f508d45f7a69..0b86aa1b12f1 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -825,7 +825,6 @@ static void ubd_device_release(struct device *dev)
{
struct ubd *ubd_dev = dev_get_drvdata(dev);

- blk_cleanup_queue(ubd_dev->queue);
blk_mq_free_tag_set(&ubd_dev->tag_set);
*ubd_dev = ((struct ubd) DEFAULT_UBD);
}
@@ -865,17 +864,12 @@ static const struct attribute_group *ubd_attr_groups[] = {
NULL,
};

-static int ubd_disk_register(int major, u64 size, int unit,
- struct gendisk **disk_out)
+static void ubd_disk_register(int major, u64 size, int unit,
+ struct gendisk *disk)
{
- struct gendisk *disk;
-
- disk = alloc_disk(1 << UBD_SHIFT);
- if(disk == NULL)
- return -ENOMEM;
-
disk->major = major;
disk->first_minor = unit << UBD_SHIFT;
+ disk->minors = 1 << UBD_SHIFT;
disk->fops = &ubd_blops;
set_capacity(disk, size / 512);
sprintf(disk->disk_name, "ubd%c", 'a' + unit);
@@ -889,9 +883,6 @@ static int ubd_disk_register(int major, u64 size, int unit,
disk->private_data = &ubd_devs[unit];
disk->queue = ubd_devs[unit].queue;
device_add_disk(&ubd_devs[unit].pdev.dev, disk, ubd_attr_groups);
-
- *disk_out = disk;
- return 0;
}

#define ROUND_BLOCK(n) ((n + (SECTOR_SIZE - 1)) & (-SECTOR_SIZE))
@@ -903,6 +894,7 @@ static const struct blk_mq_ops ubd_mq_ops = {
static int ubd_add(int n, char **error_out)
{
struct ubd *ubd_dev = &ubd_devs[n];
+ struct gendisk *disk;
int err = 0;

if(ubd_dev->file == NULL)
@@ -927,32 +919,24 @@ static int ubd_add(int n, char **error_out)
if (err)
goto out;

- ubd_dev->queue = blk_mq_init_queue(&ubd_dev->tag_set);
- if (IS_ERR(ubd_dev->queue)) {
- err = PTR_ERR(ubd_dev->queue);
+ disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
+ if (IS_ERR(disk)) {
+ err = PTR_ERR(disk);
goto out_cleanup_tags;
}
+ ubd_dev->queue = disk->queue;

- ubd_dev->queue->queuedata = ubd_dev;
blk_queue_write_cache(ubd_dev->queue, true, false);
-
blk_queue_max_segments(ubd_dev->queue, MAX_SG);
blk_queue_segment_boundary(ubd_dev->queue, PAGE_SIZE - 1);
- err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
- if(err){
- *error_out = "Failed to register device";
- goto out_cleanup_tags;
- }
-
- err = 0;
-out:
- return err;
+ ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, disk);
+ ubd_gendisk[n] = disk;
+ return 0;

out_cleanup_tags:
blk_mq_free_tag_set(&ubd_dev->tag_set);
- if (!(IS_ERR(ubd_dev->queue)))
- blk_cleanup_queue(ubd_dev->queue);
- goto out;
+out:
+ return err;
}

static int ubd_config(char *str, char **error_out)
@@ -1055,7 +1039,7 @@ static int ubd_remove(int n, char **error_out)
ubd_gendisk[n] = NULL;
if(disk != NULL){
del_gendisk(disk);
- put_disk(disk);
+ blk_cleanup_disk(disk);
}

err = 0;
--
2.30.2