Hi,
在 2025/04/10 16:06, LongPing Wei 写道:
On 2025/4/10 15:36, Christoph Hellwig wrote:
On Thu, Apr 10, 2025 at 11:09:04AM +0800, LongPing Wei wrote:
Fix the compile error when dm-bufio is built as a module.
1. dm-bufio module use blk_flush_plug();
2. blk_flush_plug is an inline function and it calls __blk_flush_plug.
Then don't call blk_flush_plug from dm-bufio, as drivers should not
micro-manage plug flushing.
Note that at least in current upstream and linux-next dm-bufio does
not actually call blk_flush_plug, so I'm not sure where your
report comes from.
Hi, Christoph
Stephen reported that a compile error happened when he tried merging
device-mapper tree.
Hi all,
After merging the device-mapper tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:
ERROR: modpost: "__blk_flush_plug" [drivers/md/dm-bufio.ko] undefined!
Caused by commit
713ff5c782f5 ("dm-bufio: improve the performance of
__dm_bufio_prefetch")
I have used the device-mapper tree from next-20250409 for today.
More details are here.
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=for-next&id=713ff5c782f5a497bd0e93ca19607daf5bf34005
So, this patch has compile problem, I think it should be removed from
dm tree.
BTW, I don't get it from commit message, why you need to flush plug when
bio is not contiguous. Other than bio merge, plug is also benefit from
batch submitting:
__blk_mq_flush_plug_list
q->mq_ops->queue_rqs(&plug->mq_list)
Thanks,
Kuai
https://lore.kernel.org/dm-devel/66bf8a8e-0a7d-47b8-9676-dc2e8c596...@oppo.com/T/#t
Thanks
LongPing
.
