Messages in this thread | | | Subject | Re: [PATCH 10/10] mm/migrate.c: call detach_page_private to cleanup code | From | Guoqing Jiang <> | Date | Tue, 19 May 2020 22:44:42 +0200 |
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Hi Andrew,
On 5/19/20 9:35 AM, Guoqing Jiang wrote: > On 5/19/20 7:12 AM, Andrew Morton wrote: >> On Sun, 17 May 2020 23:47:18 +0200 Guoqing Jiang >> <guoqing.jiang@cloud.ionos.com> wrote: >> >>> We can cleanup code a little by call detach_page_private here. >>> >>> ... >>> >>> --- a/mm/migrate.c >>> +++ b/mm/migrate.c >>> @@ -804,10 +804,7 @@ static int __buffer_migrate_page(struct >>> address_space *mapping, >>> if (rc != MIGRATEPAGE_SUCCESS) >>> goto unlock_buffers; >>> - ClearPagePrivate(page); >>> - set_page_private(newpage, page_private(page)); >>> - set_page_private(page, 0); >>> - put_page(page); >>> + set_page_private(newpage, detach_page_private(page)); >>> get_page(newpage); >>> bh = head; >> mm/migrate.c: In function '__buffer_migrate_page': >> ./include/linux/mm_types.h:243:52: warning: assignment makes integer >> from pointer without a cast [-Wint-conversion] >> #define set_page_private(page, v) ((page)->private = (v)) >> ^ >> mm/migrate.c:800:2: note: in expansion of macro 'set_page_private' >> set_page_private(newpage, detach_page_private(page)); >> ^~~~~~~~~~~~~~~~ >> >> The fact that set_page_private(detach_page_private()) generates a type >> mismatch warning seems deeply wrong, surely. >> >> Please let's get the types sorted out - either unsigned long or void *, >> not half-one and half-the other. Whatever needs the least typecasting >> at callsites, I suggest. > > Sorry about that, I should notice the warning before. I will double > check if other > places need the typecast or not, then send a new version.
Only this patch missed the typecast. I guess I just need to send an updated patch to replace this one (I am fine to send a new patch set if you want), sorry again for the trouble.
> >> And can we please implement set_page_private() and page_private() with >> inlined C code? There is no need for these to be macros. > > Just did a quick change. > > -#define page_private(page) ((page)->private) > -#define set_page_private(page, v) ((page)->private = (v)) > +static inline unsigned long page_private(struct page *page) > +{ > + return page->private; > +} > + > +static inline void set_page_private(struct page *page, unsigned long > priv_data) > +{ > + page->private = priv_data; > +} > > Then I get error like. > > fs/erofs/zdata.h: In function ‘z_erofs_onlinepage_index’: > fs/erofs/zdata.h:126:8: error: lvalue required as unary ‘&’ operand > u.v = &page_private(page); > ^ > > I guess it is better to keep page_private as macro, please correct me > in case I > missed something.
Lost of problems need to be fixed if change page_private to inline function, so I think it is better to keep it and only convert set_page_private.
mm/compaction.c: In function ‘isolate_migratepages_block’: ./include/linux/compiler.h:287:20: error: lvalue required as unary ‘&’ operand __read_once_size(&(x), __u.__c, sizeof(x)); \ ^ ./include/linux/compiler.h:293:22: note: in expansion of macro ‘__READ_ONCE’ #define READ_ONCE(x) __READ_ONCE(x, 1) ^~~~~~~~~~~ mm/internal.h:293:34: note: in expansion of macro ‘READ_ONCE’ #define page_order_unsafe(page) READ_ONCE(page_private(page))
Thanks, Guoqing
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