On Tue, Nov 24, 2020 at 11:21:13AM -0800, Ira Weiny wrote:
> On Tue, Nov 24, 2020 at 02:19:41PM +0000, Matthew Wilcox wrote:
> > On Mon, Nov 23, 2020 at 10:07:39PM -0800, ira.weiny@xxxxxxxxx wrote:
> > > +static inline void memzero_page(struct page *page, size_t offset, size_t len)
> > > +{
> > > + memset_page(page, 0, offset, len);
> > > +}
> >
> > This is a less-capable zero_user_segments().
>
> Actually it is a duplicate of zero_user()... Sorry I did not notice those...
> :-(
>
> Why are they called '_user_'?
git knows ...
commit 01f2705daf5a36208e69d7cf95db9c330f843af6
Author: Nate Diller <nate.diller@xxxxxxxxx>
Date: Wed May 9 02:35:07 2007 -0700
fs: convert core functions to zero_user_page
It's very common for file systems to need to zero part or all of a page,
the simplist way is just to use kmap_atomic() and memset(). There's
actually a library function in include/linux/highmem.h that does exactly
that, but it's confusingly named memclear_highpage_flush(), which is
descriptive of *how* it does the work rather than what the *purpose* is.
So this patchset renames the function to zero_user_page(), and calls it
from the various places that currently open code it.
This first patch introduces the new function call, and converts all the
core kernel callsites, both the open-coded ones and the old
memclear_highpage_flush() ones. Following this patch is a series of
conversions for each file system individually, per AKPM, and finally a
patch deprecating the old call. The diffstat below shows the entire
patchset.
