* [RFC] Renaming page_offset() to page_pos()
@ 2020-04-03 15:33 Matthew Wilcox
2020-04-07 19:09 ` William Kucharski
0 siblings, 1 reply; 2+ messages in thread
From: Matthew Wilcox @ 2020-04-03 15:33 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-mm, linux-kernel
Without looking at the source, can you tell me what page_offset() does?
At least one regular contributor thought it meant the pgoff_t of this
page within the file. It's actually the byte offset of this page into
the file.
We have a perfectly good name for byte offset into the file --
file->f_pos. So I propose renaming it to page_pos(). To minimise
disruption to other development, I'm going to send Linus a pull request
at the end of the merge window with the results of this coccinelle script:
@@ expression a; @@
- page_offset(a)
+ page_pos(a)
I've reviewed the output and the only slight weirdness is an extra space
in casts:
btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
"page private not zero on page %llu",
- (unsigned long long)page_offset(page));
+ (unsigned long long) page_pos(page));
Sometimes Coccinelle fixes the surrounding whitespace to be better
than it currently is:
- ow->bv[i].bv_len = min(page_offset(ow->pages[i]) + PAGE_SIZE,
- ow->off + ow->len) -
- max(ow->off, page_offset(ow->pages[i]));
+ ow->bv[i].bv_len = min(page_pos(ow->pages[i]) + PAGE_SIZE,
+ ow->off + ow->len) -
+ max(ow->off, page_pos(ow->pages[i]));
(it's still bad, but it's an improvement)
Any objections? Anyone got a better name than page_pos()?
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [RFC] Renaming page_offset() to page_pos()
2020-04-03 15:33 [RFC] Renaming page_offset() to page_pos() Matthew Wilcox
@ 2020-04-07 19:09 ` William Kucharski
0 siblings, 0 replies; 2+ messages in thread
From: William Kucharski @ 2020-04-07 19:09 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: linux-fsdevel, linux-mm, linux-kernel
page_pos seems quite reasonable to me.
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
> On Apr 3, 2020, at 9:33 AM, Matthew Wilcox <willy@infradead.org> wrote:
>
> Without looking at the source, can you tell me what page_offset() does?
>
> At least one regular contributor thought it meant the pgoff_t of this
> page within the file. It's actually the byte offset of this page into
> the file.
>
> We have a perfectly good name for byte offset into the file --
> file->f_pos. So I propose renaming it to page_pos(). To minimise
> disruption to other development, I'm going to send Linus a pull request
> at the end of the merge window with the results of this coccinelle script:
>
> @@ expression a; @@
> - page_offset(a)
> + page_pos(a)
>
> I've reviewed the output and the only slight weirdness is an extra space
> in casts:
>
> btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
> "page private not zero on page %llu",
> - (unsigned long long)page_offset(page));
> + (unsigned long long) page_pos(page));
>
> Sometimes Coccinelle fixes the surrounding whitespace to be better
> than it currently is:
>
> - ow->bv[i].bv_len = min(page_offset(ow->pages[i]) + PAGE_SIZE,
> - ow->off + ow->len) -
> - max(ow->off, page_offset(ow->pages[i]));
> + ow->bv[i].bv_len = min(page_pos(ow->pages[i]) + PAGE_SIZE,
> + ow->off + ow->len) -
> + max(ow->off, page_pos(ow->pages[i]));
>
> (it's still bad, but it's an improvement)
>
> Any objections? Anyone got a better name than page_pos()?
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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