From: Shin'ichiro Kawasaki shinichiro.kawasaki@wdc.com
[ Upstream commit 2cadb8ef25a6157b5bd3e8fe0d3e23f32defec25 ]
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.c... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/null_blk/main.c | 86 ++++++++++++++++++++--------------- 1 file changed, 49 insertions(+), 37 deletions(-)
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 175566a71bb3f..41c2cd5818b4a 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_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);