| Message ID | 20250321053148.1434076-2-gshan@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fix parameter passed to page_mapcount_is_type() | expand |
On 21.03.25 06:31, Gavin Shan wrote: > As the comments of page_mapcount_is_type() indicate, the parameter > passed to the function should be one more than page->__mapcount. > However, page->__mapcount (equivalent to page->page_type) is passed to > the function by commit 4ffca5a96678 ("mm: support only one page_type per > page") where page_type_has_type() is replaced by page_mapcount_is_type(), > but the parameter isn't adjusted. > > Fix the parameter passed to page_mapcount_is_type() to be (page->__mapcount > + 1). > > Fixes: 4ffca5a96678 ("mm: support only one page_type per page") > Cc: stable@vger.kernel.org # v6.12+ > Signed-off-by: Gavin Shan <gshan@redhat.com> > --- > include/linux/page-flags.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 36d283552f80..ad87b4cf1f9a 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -950,7 +950,7 @@ static inline bool page_mapcount_is_type(unsigned int mapcount) > > static inline bool page_has_type(const struct page *page) > { > - return page_mapcount_is_type(data_race(page->page_type)); > + return page_mapcount_is_type(data_race(page->page_type) + 1); Probably we should just call page_type_has_type() instead?
On 3/21/25 8:13 PM, David Hildenbrand wrote: > On 21.03.25 06:31, Gavin Shan wrote: >> As the comments of page_mapcount_is_type() indicate, the parameter >> passed to the function should be one more than page->__mapcount. >> However, page->__mapcount (equivalent to page->page_type) is passed to >> the function by commit 4ffca5a96678 ("mm: support only one page_type per >> page") where page_type_has_type() is replaced by page_mapcount_is_type(), >> but the parameter isn't adjusted. >> >> Fix the parameter passed to page_mapcount_is_type() to be (page->__mapcount >> + 1). >> >> Fixes: 4ffca5a96678 ("mm: support only one page_type per page") >> Cc: stable@vger.kernel.org # v6.12+ >> Signed-off-by: Gavin Shan <gshan@redhat.com> >> --- >> include/linux/page-flags.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h >> index 36d283552f80..ad87b4cf1f9a 100644 >> --- a/include/linux/page-flags.h >> +++ b/include/linux/page-flags.h >> @@ -950,7 +950,7 @@ static inline bool page_mapcount_is_type(unsigned int mapcount) >> static inline bool page_has_type(const struct page *page) >> { >> - return page_mapcount_is_type(data_race(page->page_type)); >> + return page_mapcount_is_type(data_race(page->page_type) + 1); > > Probably we should just call page_type_has_type() instead? > Yes, page_type_has_type() is better. It will be used in v2. Thanks, Gavin
On 21.03.25 12:26, Gavin Shan wrote: > On 3/21/25 8:13 PM, David Hildenbrand wrote: >> On 21.03.25 06:31, Gavin Shan wrote: >>> As the comments of page_mapcount_is_type() indicate, the parameter >>> passed to the function should be one more than page->__mapcount. >>> However, page->__mapcount (equivalent to page->page_type) is passed to >>> the function by commit 4ffca5a96678 ("mm: support only one page_type per >>> page") where page_type_has_type() is replaced by page_mapcount_is_type(), >>> but the parameter isn't adjusted. >>> >>> Fix the parameter passed to page_mapcount_is_type() to be (page->__mapcount >>> + 1). >>> >>> Fixes: 4ffca5a96678 ("mm: support only one page_type per page") >>> Cc: stable@vger.kernel.org # v6.12+ >>> Signed-off-by: Gavin Shan <gshan@redhat.com> >>> --- >>> include/linux/page-flags.h | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h >>> index 36d283552f80..ad87b4cf1f9a 100644 >>> --- a/include/linux/page-flags.h >>> +++ b/include/linux/page-flags.h >>> @@ -950,7 +950,7 @@ static inline bool page_mapcount_is_type(unsigned int mapcount) >>> static inline bool page_has_type(const struct page *page) >>> { >>> - return page_mapcount_is_type(data_race(page->page_type)); >>> + return page_mapcount_is_type(data_race(page->page_type) + 1); >> >> Probably we should just call page_type_has_type() instead? >> > > Yes, page_type_has_type() is better. It will be used in v2. Feel free to add my Acked-by: David Hildenbrand <david@redhat.com>
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 36d283552f80..ad87b4cf1f9a 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -950,7 +950,7 @@ static inline bool page_mapcount_is_type(unsigned int mapcount) static inline bool page_has_type(const struct page *page) { - return page_mapcount_is_type(data_race(page->page_type)); + return page_mapcount_is_type(data_race(page->page_type) + 1); } #define FOLIO_TYPE_OPS(lname, fname) \
As the comments of page_mapcount_is_type() indicate, the parameter passed to the function should be one more than page->__mapcount. However, page->__mapcount (equivalent to page->page_type) is passed to the function by commit 4ffca5a96678 ("mm: support only one page_type per page") where page_type_has_type() is replaced by page_mapcount_is_type(), but the parameter isn't adjusted. Fix the parameter passed to page_mapcount_is_type() to be (page->__mapcount + 1). Fixes: 4ffca5a96678 ("mm: support only one page_type per page") Cc: stable@vger.kernel.org # v6.12+ Signed-off-by: Gavin Shan <gshan@redhat.com> --- include/linux/page-flags.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)