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@xxxxxxx>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
---
drivers/block/null_blk/main.c | 90 ++++++++++++++++++++---------------
1 file changed, 51 insertions(+), 39 deletions(-)
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index d94ef37480bd..0725d221cff4 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -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);
--
2.47.0
