null_blk: refactor tag_set setup

Move the tagset initialization out of null_add_dev into a new
null_setup_tagset helper, and move the shared vs local differences
out of null_init_tag_set into the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240220093248.3290292-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 89e63d1c61036274565dd4883145100fba983973..03c3917a56fa2891722e8cfb171c798f167daba4 100644 (file)
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1759,55 +1759,65 @@ static int null_gendisk_register(struct nullb *nullb)
        return add_disk(disk);
 }
 
-static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set)
+static int null_init_tag_set(struct blk_mq_tag_set *set, int poll_queues)
 {
-       unsigned int flags = BLK_MQ_F_SHOULD_MERGE;
-       int hw_queues, numa_node;
-       unsigned int queue_depth;
-       int poll_queues;
-
-       if (nullb) {
-               hw_queues = nullb->dev->submit_queues;
-               poll_queues = nullb->dev->poll_queues;
-               queue_depth = nullb->dev->hw_queue_depth;
-               numa_node = nullb->dev->home_node;
-               if (nullb->dev->no_sched)
-                       flags |= BLK_MQ_F_NO_SCHED;
-               if (nullb->dev->shared_tag_bitmap)
-                       flags |= BLK_MQ_F_TAG_HCTX_SHARED;
-               if (nullb->dev->blocking)
-                       flags |= BLK_MQ_F_BLOCKING;
-       } else {
-               hw_queues = g_submit_queues;
-               poll_queues = g_poll_queues;
-               queue_depth = g_hw_queue_depth;
-               numa_node = g_home_node;
-               if (g_no_sched)
-                       flags |= BLK_MQ_F_NO_SCHED;
-               if (g_shared_tag_bitmap)
-                       flags |= BLK_MQ_F_TAG_HCTX_SHARED;
-               if (g_blocking)
-                       flags |= BLK_MQ_F_BLOCKING;
-       }
-
        set->ops = &null_mq_ops;
-       set->cmd_size   = sizeof(struct nullb_cmd);
-       set->flags = flags;
-       set->driver_data = nullb;
-       set->nr_hw_queues = hw_queues;
-       set->queue_depth = queue_depth;
-       set->numa_node = numa_node;
+       set->cmd_size = sizeof(struct nullb_cmd);
        set->timeout = 5 * HZ;
+       set->nr_maps = 1;
        if (poll_queues) {
                set->nr_hw_queues += poll_queues;
-               set->nr_maps = 3;
-       } else {
-               set->nr_maps = 1;
+               set->nr_maps += 2;
        }
-
        return blk_mq_alloc_tag_set(set);
 }
 
+static int null_init_global_tag_set(void)
+{
+       int error;
+
+       if (tag_set.ops)
+               return 0;
+
+       tag_set.nr_hw_queues = g_submit_queues;
+       tag_set.queue_depth = g_hw_queue_depth;
+       tag_set.numa_node = g_home_node;
+       tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+       if (g_no_sched)
+               tag_set.flags |= BLK_MQ_F_NO_SCHED;
+       if (g_shared_tag_bitmap)
+               tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED;
+       if (g_blocking)
+               tag_set.flags |= BLK_MQ_F_BLOCKING;
+
+       error = null_init_tag_set(&tag_set, g_poll_queues);
+       if (error)
+               tag_set.ops = NULL;
+       return error;
+}
+
+static int null_setup_tagset(struct nullb *nullb)
+{
+       if (nullb->dev->shared_tags) {
+               nullb->tag_set = &tag_set;
+               return null_init_global_tag_set();
+       }
+
+       nullb->tag_set = &nullb->__tag_set;
+       nullb->tag_set->driver_data = nullb;
+       nullb->tag_set->nr_hw_queues = nullb->dev->submit_queues;
+       nullb->tag_set->queue_depth = nullb->dev->hw_queue_depth;
+       nullb->tag_set->numa_node = nullb->dev->home_node;
+       nullb->tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
+       if (nullb->dev->no_sched)
+               nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED;
+       if (nullb->dev->shared_tag_bitmap)
+               nullb->tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
+       if (nullb->dev->blocking)
+               nullb->tag_set->flags |= BLK_MQ_F_BLOCKING;
+       return null_init_tag_set(nullb->tag_set, nullb->dev->poll_queues);
+}
+
 static int null_validate_conf(struct nullb_device *dev)
 {
        if (dev->queue_mode == NULL_Q_RQ) {
@@ -1904,21 +1914,7 @@ static int null_add_dev(struct nullb_device *dev)
        if (rv)
                goto out_free_nullb;
 
-       if (dev->shared_tags) {
-               if (!tag_set.ops) {
-                       rv = null_init_tag_set(NULL, &tag_set);
-                       if (rv) {
-                               tag_set.ops = NULL;
-                               goto out_cleanup_queues;
-                       }
-               }
-               nullb->tag_set = &tag_set;
-               rv = 0;
-       } else {
-               nullb->tag_set = &nullb->__tag_set;
-               rv = null_init_tag_set(nullb, nullb->tag_set);
-       }
-
+       rv = null_setup_tagset(nullb);
        if (rv)
                goto out_cleanup_queues;