Commit 2cadb8ef authored by Shin'ichiro Kawasaki's avatar Shin'ichiro Kawasaki Committed by Jens Axboe
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null_blk: generate null_blk configfs features string 



The null_blk configfs file 'features' provides a string that lists
available null_blk features for userspace programs to reference.
The string is defined as a long constant in the code, which tends to be
forgotten for updates. It also causes checkpatch.pl to report
"WARNING: quoted string split across lines".

To avoid these drawbacks, generate the feature string on the fly. Refer
to the ca_name field of each element in the nullb_device_attrs table and
concatenate them in the given buffer. Also, sorted nullb_device_attrs
table elements in alphabetical order.

Of note is that the feature "index" was missing before this commit.
This commit adds it to the generated string.

Suggested-by: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarDamien Le Moal <dlemoal@kernel.org>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarShin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20250226100613.1622564-2-shinichiro.kawasaki@wdc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 603f9be2

drivers/block/null_blk/main.c

+49 −37
Original line number Diff line number Diff line
@@ -592,41 +592,41 @@ static ssize_t nullb_device_zone_offline_store(struct config_item *item, 
CONFIGFS_ATTR_WO(nullb_device_, zone_offline);



static struct configfs_attribute *nullb_device_attrs[] = {

	&nullb_device_attr_size,

	&nullb_device_attr_badblocks,

	&nullb_device_attr_blocking,

	&nullb_device_attr_blocksize,

	&nullb_device_attr_cache_size,

	&nullb_device_attr_completion_nsec,

	&nullb_device_attr_submit_queues,

	&nullb_device_attr_poll_queues,

	&nullb_device_attr_discard,

	&nullb_device_attr_fua,

	&nullb_device_attr_home_node,

	&nullb_device_attr_queue_mode,

	&nullb_device_attr_blocksize,

	&nullb_device_attr_max_sectors,

	&nullb_device_attr_irqmode,

	&nullb_device_attr_hw_queue_depth,

	&nullb_device_attr_index,

	&nullb_device_attr_blocking,

	&nullb_device_attr_use_per_node_hctx,

	&nullb_device_attr_power,

	&nullb_device_attr_memory_backed,

	&nullb_device_attr_discard,

	&nullb_device_attr_irqmode,

	&nullb_device_attr_max_sectors,

	&nullb_device_attr_mbps,

	&nullb_device_attr_cache_size,

	&nullb_device_attr_badblocks,

	&nullb_device_attr_zoned,

	&nullb_device_attr_zone_size,

	&nullb_device_attr_memory_backed,

	&nullb_device_attr_no_sched,

	&nullb_device_attr_poll_queues,

	&nullb_device_attr_power,

	&nullb_device_attr_queue_mode,

	&nullb_device_attr_rotational,

	&nullb_device_attr_shared_tag_bitmap,

	&nullb_device_attr_shared_tags,

	&nullb_device_attr_size,

	&nullb_device_attr_submit_queues,

	&nullb_device_attr_use_per_node_hctx,

	&nullb_device_attr_virt_boundary,

	&nullb_device_attr_zone_append_max_sectors,

	&nullb_device_attr_zone_capacity,

	&nullb_device_attr_zone_nr_conv,

	&nullb_device_attr_zone_max_open,

	&nullb_device_attr_zone_full,

	&nullb_device_attr_zone_max_active,

	&nullb_device_attr_zone_append_max_sectors,

	&nullb_device_attr_zone_readonly,

	&nullb_device_attr_zone_max_open,

	&nullb_device_attr_zone_nr_conv,

	&nullb_device_attr_zone_offline,

	&nullb_device_attr_zone_full,

	&nullb_device_attr_virt_boundary,

	&nullb_device_attr_no_sched,

	&nullb_device_attr_shared_tags,

	&nullb_device_attr_shared_tag_bitmap,

	&nullb_device_attr_fua,

	&nullb_device_attr_rotational,

	&nullb_device_attr_zone_readonly,

	&nullb_device_attr_zone_size,

	&nullb_device_attr_zoned,

	NULL,

};
@@ -704,16 +704,28 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item) 


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

{

	return snprintf(page, PAGE_SIZE,

			"badblocks,blocking,blocksize,cache_size,fua,"

			"completion_nsec,discard,home_node,hw_queue_depth,"

			"irqmode,max_sectors,mbps,memory_backed,no_sched,"

			"poll_queues,power,queue_mode,shared_tag_bitmap,"

			"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,"

			"rotational\n");



	struct configfs_attribute **entry;

	char delimiter = ',';

	size_t left = PAGE_SIZE;

	size_t written = 0;

	int ret;



	for (entry = &nullb_device_attrs[0]; *entry && left > 0; entry++) {

		if (!*(entry + 1))

			delimiter = '\n';

		ret = snprintf(page + written, left, "%s%c", (*entry)->ca_name,

			       delimiter);

		if (ret >= left) {

			WARN_ONCE(1, "Too many null_blk features to print\n");

			memzero_explicit(page, PAGE_SIZE);

			return -ENOBUFS;

		}

		left -= ret;

		written += ret;

	}



	return written;

}



CONFIGFS_ATTR_RO(memb_group_, features);