Hi,
在 2023/05/10 13:40, Lukas Bulwahn 写道:
On Wed, May 10, 2023 at 5:24 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
Hi,
在 2023/05/08 12:37, Lukas Bulwahn 写道:
Dear Yu Kuai, dear Christoph, dear Jens,
The commit b11d31ae01e6 ("blk-wbt: remove unnecessary check in
wbt_enable_default()") removes the only reference to the config
BLK_WBT_MQ in the kernel tree.
The commit comes with the statement "If CONFIG_BLK_WBT_MQ is disabled,
wbt_init() won't do anything.". The statement "If CONFIG_BLK_WBT is
disabled, wbt_init() won't do anything." (note: CONFIG_BLK_WBT vs.
CONFIG_BLK_WBT_MQ) is certainly true, but I do not see that "If
CONFIG_BLK_WBT_MQ is disabled, wbt_init() won't do anything.", but I
believe it would simply do what wbt_init() does with CONFIG_BLK_WBT
being enabled.
Now, it seems that with this commit applied, the intended switch of
the config BLK_WBT_MQ is gone, and the config really now has no effect
at all.
So, I am a bit puzzled:
1. Either the config BLK_WBT_MQ does have an effect somewhere, but one
cannot find its reference with 'git grep -i "BLK_WBT_MQ" .' --- so, my
investigation is just incomplete or wrong, or
2. We really do not need this further build config BLK_WBT_MQ beyond
the other configs already there --- then this config should just be
removed, or
3. the commit unintentionally broke the purpose of the config
BLK_WBT_MQ --- then this commit above should be reverted.
Thanks for the report, it's the above case and it's my mistake.
I will fix this.
Kuai, thanks for letting me know. Feel free to add a "Reported-by:
Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>" tag, and to include in the
list of recipients when you send out the fix to the mailing list.
I just send the fix, sorry that I forgot to cc you...
https://lore.kernel.org/all/20230511014509.679482-2-yukuai1@xxxxxxxxxxxxxxx/
Thanks,
Kuai
I am glad to see that my investigation of kernel code is finding some
issues that we can fix.
Lukas
.
