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null_blk: generate null_blk configfs features string

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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: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20250226100613.1622564-2-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shin'ichiro Kawasaki
2025-02-26 19:06:09 +09:00
committed by Jens Axboe
parent 603f9be21c
commit 2cadb8ef25
1 changed files with 51 additions and 39 deletions
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90
drivers/block/null_blk/main.c
View File

@@ -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_completion_nsec,
&nullb_device_attr_submit_queues,
&nullb_device_attr_poll_queues,
&nullb_device_attr_home_node,
&nullb_device_attr_queue_mode,
&nullb_device_attr_badblocks,
&nullb_device_attr_blocking,
&nullb_device_attr_blocksize,
&nullb_device_attr_max_sectors,
&nullb_device_attr_irqmode,
&nullb_device_attr_cache_size,
&nullb_device_attr_completion_nsec,
&nullb_device_attr_discard,
&nullb_device_attr_fua,
&nullb_device_attr_home_node,
&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_zone_capacity,
&nullb_device_attr_zone_nr_conv,
&nullb_device_attr_zone_max_open,
&nullb_device_attr_zone_max_active,
&nullb_device_attr_zone_append_max_sectors,
&nullb_device_attr_zone_readonly,
&nullb_device_attr_zone_offline,
&nullb_device_attr_zone_full,
&nullb_device_attr_virt_boundary,
&nullb_device_attr_memory_backed,
&nullb_device_attr_no_sched,
&nullb_device_attr_shared_tags,
&nullb_device_attr_shared_tag_bitmap,
&nullb_device_attr_fua,
&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_full,
&nullb_device_attr_zone_max_active,
&nullb_device_attr_zone_max_open,
&nullb_device_attr_zone_nr_conv,
&nullb_device_attr_zone_offline,
&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);