Messages in this thread | | | Date | Wed, 30 Mar 2022 18:58:21 +0800 | Subject | Re: [PATCH v11 1/8] dax: Introduce holder for dax_device | From | Shiyang Ruan <> |
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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.
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