[PATCH 06/26] brd: convert to blk_alloc_disk/blk_cleanup_disk

Christoph Hellwig
2021-05-21T05:52:03Z

Convert the brd driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation. This also
allows to remove the request_queue pointer in struct request_queue,
and to simplify the initialization as blk_cleanup_disk can be called
on any disk returned from blk_alloc_disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/block/brd.c | 94 ++++++++++++++++-----------------------------
1 file changed, 33 insertions(+), 61 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 7562cf30b14e..95694113e38e 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -38,9 +38,7 @@
* device).
*/
struct brd_device {
- int brd_number;
-
- struct request_queue *brd_queue;
+ int brd_number;
struct gendisk *brd_disk;
struct list_head brd_list;

@@ -372,7 +370,7 @@ static LIST_HEAD(brd_devices);
static DEFINE_MUTEX(brd_devices_mutex);
static struct dentry *brd_debugfs_dir;

-static struct brd_device *brd_alloc(int i)
+static int brd_alloc(int i)
{
struct brd_device *brd;
struct gendisk *disk;
@@ -380,64 +378,55 @@ static struct brd_device *brd_alloc(int i)

brd = kzalloc(sizeof(*brd), GFP_KERNEL);
if (!brd)
- goto out;
+ return -ENOMEM;
brd->brd_number = i;
spin_lock_init(&brd->brd_lock);
INIT_RADIX_TREE(&brd->brd_pages, GFP_ATOMIC);

- brd->brd_queue = blk_alloc_queue(NUMA_NO_NODE);
- if (!brd->brd_queue)
- goto out_free_dev;
-
snprintf(buf, DISK_NAME_LEN, "ram%d", i);
if (!IS_ERR_OR_NULL(brd_debugfs_dir))
debugfs_create_u64(buf, 0444, brd_debugfs_dir,
&brd->brd_nr_pages);

- /* This is so fdisk will align partitions on 4k, because of
- * direct_access API needing 4k alignment, returning a PFN
- * (This is only a problem on very small devices <= 4M,
- * otherwise fdisk will align on 1M. Regardless this call
- * is harmless)
- */
- blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE);
- disk = brd->brd_disk = alloc_disk(max_part);
+ disk = brd->brd_disk = blk_alloc_disk(NUMA_NO_NODE);
if (!disk)
- goto out_free_queue;
+ goto out_free_dev;
+
disk->major = RAMDISK_MAJOR;
disk->first_minor = i * max_part;
+ disk->minors = max_part;
disk->fops = &brd_fops;
disk->private_data = brd;
disk->flags = GENHD_FL_EXT_DEVT;
strlcpy(disk->disk_name, buf, DISK_NAME_LEN);
set_capacity(disk, rd_size * 2);
+
+ /*
+ * This is so fdisk will align partitions on 4k, because of
+ * direct_access API needing 4k alignment, returning a PFN
+ * (This is only a problem on very small devices <= 4M,
+ * otherwise fdisk will align on 1M. Regardless this call
+ * is harmless)
+ */
+ blk_queue_physical_block_size(disk->queue, PAGE_SIZE);

/* Tell the block layer that this is not a rotational device */
- blk_queue_flag_set(QUEUE_FLAG_NONROT, brd->brd_queue);
- blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, brd->brd_queue);
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
+ blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
+ add_disk(disk);
+ list_add_tail(&brd->brd_list, &brd_devices);

- return brd;
+ return 0;

-out_free_queue:
- blk_cleanup_queue(brd->brd_queue);
out_free_dev:
kfree(brd);
-out:
- return NULL;
-}
-
-static void brd_free(struct brd_device *brd)
-{
- put_disk(brd->brd_disk);
- blk_cleanup_queue(brd->brd_queue);
- brd_free_pages(brd);
- kfree(brd);
+ return -ENOMEM;
}

static void brd_probe(dev_t dev)
{
- struct brd_device *brd;
int i = MINOR(dev) / max_part;
+ struct brd_device *brd;

mutex_lock(&brd_devices_mutex);
list_for_each_entry(brd, &brd_devices, brd_list) {
@@ -445,13 +434,7 @@ static void brd_probe(dev_t dev)
goto out_unlock;
}

- brd = brd_alloc(i);
- if (brd) {
- brd->brd_disk->queue = brd->brd_queue;
- add_disk(brd->brd_disk);
- list_add_tail(&brd->brd_list, &brd_devices);
- }
-
+ brd_alloc(i);
out_unlock:
mutex_unlock(&brd_devices_mutex);
}
@@ -460,7 +443,9 @@ static void brd_del_one(struct brd_device *brd)
{
list_del(&brd->brd_list);
del_gendisk(brd->brd_disk);
- brd_free(brd);
+ blk_cleanup_disk(brd->brd_disk);
+ brd_free_pages(brd);
+ kfree(brd);
}

static inline void brd_check_and_reset_par(void)
@@ -485,7 +470,7 @@ static inline void brd_check_and_reset_par(void)
static int __init brd_init(void)
{
struct brd_device *brd, *next;
- int i;
+ int err, i;

/*
* brd module now has a feature to instantiate underlying device
@@ -511,22 +496,11 @@ static int __init brd_init(void)

mutex_lock(&brd_devices_mutex);
for (i = 0; i < rd_nr; i++) {
- brd = brd_alloc(i);
- if (!brd)
+ err = brd_alloc(i);
+ if (err)
goto out_free;
- list_add_tail(&brd->brd_list, &brd_devices);
}

- /* point of no return */
-
- list_for_each_entry(brd, &brd_devices, brd_list) {
- /*
- * associate with queue just before adding disk for
- * avoiding to mess up failure path
- */
- brd->brd_disk->queue = brd->brd_queue;
- add_disk(brd->brd_disk);
- }
mutex_unlock(&brd_devices_mutex);

pr_info("brd: module loaded\n");
@@ -535,15 +509,13 @@ static int __init brd_init(void)
out_free:
debugfs_remove_recursive(brd_debugfs_dir);

- list_for_each_entry_safe(brd, next, &brd_devices, brd_list) {
- list_del(&brd->brd_list);
- brd_free(brd);
- }
+ list_for_each_entry_safe(brd, next, &brd_devices, brd_list)
+ brd_del_one(brd);
mutex_unlock(&brd_devices_mutex);
unregister_blkdev(RAMDISK_MAJOR, "ramdisk");

pr_info("brd: module NOT loaded !!!\n");
- return -ENOMEM;
+ return err;
}

static void __exit brd_exit(void)
--
2.30.2