Commit b56426bc authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

null_blk: Add rotational feature support 



To facilitate testing of kernel functions related to the rotational
feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational
bit support), add the rotational boolean configfs attribute and module
parameter to the null_blk driver. If set, a null block device will
report being a rotational device through it queue limits features with
the BLK_FEAT_ROTATIONAL flag.

Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20241126000956.95983-1-dlemoal@kernel.org


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f6661b1d

drivers/block/null_blk/main.c

+12 −1
Original line number Diff line number Diff line
@@ -266,6 +266,10 @@ static bool g_zone_full; 
module_param_named(zone_full, g_zone_full, bool, S_IRUGO);

MODULE_PARM_DESC(zone_full, "Initialize the sequential write required zones of a zoned device to be full. Default: false");



static bool g_rotational;

module_param_named(rotational, g_rotational, bool, S_IRUGO);

MODULE_PARM_DESC(rotational, "Set the rotational feature for the device. Default: false");



static struct nullb_device *null_alloc_dev(void);

static void null_free_dev(struct nullb_device *dev);

static void null_del_dev(struct nullb *nullb);
@@ -468,6 +472,7 @@ NULLB_DEVICE_ATTR(no_sched, bool, NULL); 
NULLB_DEVICE_ATTR(shared_tags, bool, NULL);

NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);

NULLB_DEVICE_ATTR(fua, bool, NULL);

NULLB_DEVICE_ATTR(rotational, bool, NULL);



static ssize_t nullb_device_power_show(struct config_item *item, char *page)

{
@@ -621,6 +626,7 @@ static struct configfs_attribute *nullb_device_attrs[] = { 
	&nullb_device_attr_shared_tags,

	&nullb_device_attr_shared_tag_bitmap,

	&nullb_device_attr_fua,

	&nullb_device_attr_rotational,

	NULL,

};
@@ -706,7 +712,8 @@ static ssize_t memb_group_features_show(struct config_item *item, char *page) 
			"shared_tags,size,submit_queues,use_per_node_hctx,"

			"virt_boundary,zoned,zone_capacity,zone_max_active,"

			"zone_max_open,zone_nr_conv,zone_offline,zone_readonly,"

			"zone_size,zone_append_max_sectors,zone_full\n");

			"zone_size,zone_append_max_sectors,zone_full,"

			"rotational\n");

}



CONFIGFS_ATTR_RO(memb_group_, features);
@@ -793,6 +800,7 @@ static struct nullb_device *null_alloc_dev(void) 
	dev->shared_tags = g_shared_tags;

	dev->shared_tag_bitmap = g_shared_tag_bitmap;

	dev->fua = g_fua;

	dev->rotational = g_rotational;



	return dev;

}
@@ -1938,6 +1946,9 @@ static int null_add_dev(struct nullb_device *dev) 
			lim.features |= BLK_FEAT_FUA;

	}



	if (dev->rotational)

		lim.features |= BLK_FEAT_ROTATIONAL;



	nullb->disk = blk_mq_alloc_disk(nullb->tag_set, &lim, nullb);

	if (IS_ERR(nullb->disk)) {

		rv = PTR_ERR(nullb->disk);

drivers/block/null_blk/null_blk.h

+1 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ struct nullb_device { 
	bool shared_tags; /* share tag set between devices for blk-mq */

	bool shared_tag_bitmap; /* use hostwide shared tags */

	bool fua; /* Support FUA */

	bool rotational; /* Fake rotational device */

};



struct nullb {