Re: [PATCH v6 1/3] mm/gup: add make_dirty arg to put_user_pages_dirty_lock()

[John Hubbard <jhubbard@nvidia.com>]

On 8/6/19 10:40 AM, Ira Weiny wrote:
> On Sun, Aug 04, 2019 at 02:40:40PM -0700, john.hubbard@gmail.com wrote:
>> From: John Hubbard <jhubbard@nvidia.com>
>>
>> Provide a more capable variation of put_user_pages_dirty_lock(),
>> and delete put_user_pages_dirty(). This is based on the
>> following:
>>
>> 1. Lots of call sites become simpler if a bool is passed
>> into put_user_page*(), instead of making the call site
>> choose which put_user_page*() variant to call.
>>
>> 2. Christoph Hellwig's observation that set_page_dirty_lock()
>> is usually correct, and set_page_dirty() is usually a
>> bug, or at least questionable, within a put_user_page*()
>> calling chain.
>>
>> This leads to the following API choices:
>>
>>     * put_user_pages_dirty_lock(page, npages, make_dirty)
>>
>>     * There is no put_user_pages_dirty(). You have to
>>       hand code that, in the rare case that it's
>>       required.
>>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> Cc: Matthew Wilcox <willy@infradead.org>
>> Cc: Jan Kara <jack@suse.cz>
>> Cc: Ira Weiny <ira.weiny@intel.com>
>> Cc: Jason Gunthorpe <jgg@ziepe.ca>
>> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> 
> I assume this is superseded by the patch in the large series?
> 

Actually, it's the other way around (there is a note that that effect
in the admittedly wall-of-text cover letter [1] in the 34-patch series.

However, I'm trying hard to ensure that it doesn't actually matter:

* Patch 1 in the latest of each patch series, is identical

* I'm reposting the two series together.

...and yes, it might have been better to merge the two patchsets, but
the smaller one is more reviewable. And as a result, Andrew has already
merged it into the akpm tree.


[1] https://lore.kernel.org/r/20190804224915.28669-1-jhubbard@nvidia.com

thanks,
-- 
John Hubbard
NVIDIA