brd: convert to blk_alloc_disk/blk_cleanup_disk

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>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 7562cf3..9569411 100644 (file)
--- 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)