在 2022/3/30 18:13, Christoph Hellwig 写道:
On Wed, Mar 30, 2022 at 06:03:01PM +0800, Shiyang Ruan wrote:
Because I am not sure if the offset between each layer is page aligned. For
example, when pmem dirver handles ->memory_failure(), it should subtract its
->data_offset when it calls dax_holder_notify_failure().
If they aren't, none of the DAX machinery would work.
OK. Got it.
So, use page-based function signature for ->memory_failure():
int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn,
unsigned long nr_pfns, int flags);
As the code I pasted before, pmem driver will subtract its
->data_offset, which is byte-based. And the filesystem who implements
->notify_failure() will calculate the offset in unit of byte again.
So, leave its function signature byte-based, to avoid repeated conversions.
int (*notify_failure)(struct dax_device *dax_dev, u64 offset,
u64 len, int mf_flags);
What do you think?
--
Thanks,
Ruan.
