Re: [PATCH] fs/vboxsf: Replace kmap() with kmap_local_{page, folio}()

Hans de Goede
2023-06-27T18:05:45Z

Hi Matthew,

On 6/27/23 19:48, Matthew Wilcox wrote:
> On Tue, Jun 27, 2023 at 06:51:15AM -0700, Sumitra Sharma wrote:
>> +++ b/fs/vboxsf/file.c
>> @@ -234,7 +234,7 @@ static int vboxsf_read_folio(struct file *file, struct folio *folio)
>> u8 *buf;
>> int err;
>>
>> - buf = kmap(page);
>> + buf = kmap_local_folio(folio, off);
>
> Did you test this? 'off' is the offset in the _file_. Whereas
> kmap_local_folio() takes the offset within the _folio_. They have
> different types (loff_t vs size_t) to warn you that they're different
> things.

Ah yes you are completely right, off is the offset in the file
and buf should point to the *start* of a mapping of the page.

Regards,

Hans