[PATCH 25/30] xen-blkfront: use blk_mq_alloc_disk and blk_cleanup_disk

[Christoph Hellwig <hch@xxxxxx>]

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

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 drivers/block/xen-blkfront.c | 96 +++++++++++++++---------------------
 1 file changed, 39 insertions(+), 57 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index f2c1aedcdf5a..8d49f8fa98bb 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -968,48 +968,6 @@ static void blkif_set_queue_limits(struct blkfront_info 
*info)
        blk_queue_dma_alignment(rq, 511);
 }
 
-static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
-                               unsigned int physical_sector_size)
-{
-       struct request_queue *rq;
-       struct blkfront_info *info = gd->private_data;
-
-       memset(&info->tag_set, 0, sizeof(info->tag_set));
-       info->tag_set.ops = &blkfront_mq_ops;
-       info->tag_set.nr_hw_queues = info->nr_rings;
-       if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) {
-               /*
-                * When indirect descriptior is not supported, the I/O request
-                * will be split between multiple request in the ring.
-                * To avoid problems when sending the request, divide by
-                * 2 the depth of the queue.
-                */
-               info->tag_set.queue_depth =  BLK_RING_SIZE(info) / 2;
-       } else
-               info->tag_set.queue_depth = BLK_RING_SIZE(info);
-       info->tag_set.numa_node = NUMA_NO_NODE;
-       info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
-       info->tag_set.cmd_size = sizeof(struct blkif_req);
-       info->tag_set.driver_data = info;
-
-       if (blk_mq_alloc_tag_set(&info->tag_set))
-               return -EINVAL;
-       rq = blk_mq_init_queue(&info->tag_set);
-       if (IS_ERR(rq)) {
-               blk_mq_free_tag_set(&info->tag_set);
-               return PTR_ERR(rq);
-       }
-
-       rq->queuedata = info;
-       info->rq = gd->queue = rq;
-       info->gd = gd;
-       info->sector_size = sector_size;
-       info->physical_sector_size = physical_sector_size;
-       blkif_set_queue_limits(info);
-
-       return 0;
-}
-
 static const char *flush_info(struct blkfront_info *info)
 {
        if (info->feature_flush && info->feature_fua)
@@ -1146,12 +1104,36 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 
        err = xlbd_reserve_minors(minor, nr_minors);
        if (err)
-               goto out;
+               return err;
        err = -ENODEV;
 
-       gd = alloc_disk(nr_minors);
-       if (gd == NULL)
-               goto release;
+       memset(&info->tag_set, 0, sizeof(info->tag_set));
+       info->tag_set.ops = &blkfront_mq_ops;
+       info->tag_set.nr_hw_queues = info->nr_rings;
+       if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) {
+               /*
+                * When indirect descriptior is not supported, the I/O request
+                * will be split between multiple request in the ring.
+                * To avoid problems when sending the request, divide by
+                * 2 the depth of the queue.
+                */
+               info->tag_set.queue_depth =  BLK_RING_SIZE(info) / 2;
+       } else
+               info->tag_set.queue_depth = BLK_RING_SIZE(info);
+       info->tag_set.numa_node = NUMA_NO_NODE;
+       info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+       info->tag_set.cmd_size = sizeof(struct blkif_req);
+       info->tag_set.driver_data = info;
+
+       err = blk_mq_alloc_tag_set(&info->tag_set);
+       if (err)
+               goto out_release_minors;
+
+       gd = blk_mq_alloc_disk(&info->tag_set, info);
+       if (IS_ERR(gd)) {
+               err = PTR_ERR(gd);
+               goto out_free_tag_set;
+       }
 
        strcpy(gd->disk_name, DEV_NAME);
        ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
@@ -1164,14 +1146,16 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 
        gd->major = XENVBD_MAJOR;
        gd->first_minor = minor;
+       gd->minors = nr_minors;
        gd->fops = &xlvbd_block_fops;
        gd->private_data = info;
        set_capacity(gd, capacity);
 
-       if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size)) {
-               del_gendisk(gd);
-               goto release;
-       }
+       info->rq = gd->queue;
+       info->gd = gd;
+       info->sector_size = sector_size;
+       info->physical_sector_size = physical_sector_size;
+       blkif_set_queue_limits(info);
 
        xlvbd_flush(info);
 
@@ -1186,9 +1170,10 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 
        return 0;
 
- release:
+out_free_tag_set:
+       blk_mq_free_tag_set(&info->tag_set);
+out_release_minors:
        xlbd_release_minors(minor, nr_minors);
- out:
        return err;
 }
 
@@ -1217,12 +1202,9 @@ static void xlvbd_release_gendisk(struct blkfront_info 
*info)
        nr_minors = info->gd->minors;
        xlbd_release_minors(minor, nr_minors);
 
-       blk_cleanup_queue(info->rq);
-       blk_mq_free_tag_set(&info->tag_set);
-       info->rq = NULL;
-
-       put_disk(info->gd);
+       blk_cleanup_disk(info->gd);
        info->gd = NULL;
+       blk_mq_free_tag_set(&info->tag_set);
 }
 
 /* Already hold rinfo->ring_lock. */
-- 
2.30.2