null_blk: add usage hints for NVM

If CONFIG_NVM is disabled, loading null_block module with use_lightnvm=1
fails. But there are no messages and documents related to the failure.

Add the appropriate error message.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Massaged the text a bit.

Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Yasuaki Ishimatsu 2016-11-16 08:26:11 -07:00 committed by Jens Axboe
parent 0a6219a95f
commit 92153d30c7
2 changed files with 2 additions and 1 deletions

View File

@ -72,4 +72,4 @@ use_per_node_hctx=[0/1]: Default: 0
queue for each CPU node in the system.
use_lightnvm=[0/1]: Default: 0
Register device with LightNVM. Requires blk-mq to be used.
Register device with LightNVM. Requires blk-mq and CONFIG_NVM to be enabled.

View File

@ -577,6 +577,7 @@ static void null_nvm_unregister(struct nullb *nullb)
#else
static int null_nvm_register(struct nullb *nullb)
{
pr_err("null_blk: CONFIG_NVM needs to be enabled for LightNVM\n");
return -EINVAL;
}
static void null_nvm_unregister(struct nullb *nullb) {}