Re: [PATCH RFC v3 for-6.8/block 02/17] xen/blkback: use bdev api in xen_update_blkif_status()

Yu Kuai
2024-01-04T12:19:18Z

Hi, Jan!

在 2024/01/04 19:06, Jan Kara 写道:
> On Thu 21-12-23 16:56:57, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@huawei.com>
>>
>> Avoid to access bd_inode directly, prepare to remove bd_inode from
>> block_devcie.
>>
>> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
>> ---
>> drivers/block/xen-blkback/xenbus.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
>> index e34219ea2b05..e645afa4af57 100644
>> --- a/drivers/block/xen-blkback/xenbus.c
>> +++ b/drivers/block/xen-blkback/xenbus.c
>> @@ -104,8 +104,7 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
>> xenbus_dev_error(blkif->be->dev, err, "block flush");
>> return;
>> }
>> - invalidate_inode_pages2(
>> - blkif->vbd.bdev_handle->bdev->bd_inode->i_mapping);
>> + invalidate_bdev(blkif->vbd.bdev_handle->bdev);
>
> This function uses invalidate_inode_pages2() while invalidate_bdev() ends
> up using mapping_try_invalidate() and there are subtle behavioral
> differences between these two (for example invalidate_inode_pages2() tries
> to clean dirty pages using the ->launder_folio method). So I think you'll
> need helper like invalidate_bdev2() for this.

Thanks for reviewing this patch, I know the differenct between then,
what I don't understand is that why using invalidate_inode_pages2()
here. sync_blockdev() is just called and 0 is returned, I think in this
case it's safe to call invalidate_bdev() directly, or am I missing
other things?

Thanks,
Kuai

>
> Honza
>