| Message ID | 20180504183318.14415-14-willy@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/04/2018 08:33 PM, Matthew Wilcox wrote: > From: Matthew Wilcox <mawilcox@microsoft.com> > > Make hmm_data an explicit member of the struct page union. > > Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> > --- > include/linux/hmm.h | 8 ++------ > include/linux/mm_types.h | 14 +++++++++----- > 2 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/include/linux/hmm.h b/include/linux/hmm.h > index 39988924de3a..91c1b2dccbbb 100644 > --- a/include/linux/hmm.h > +++ b/include/linux/hmm.h > @@ -522,9 +522,7 @@ void hmm_devmem_remove(struct hmm_devmem *devmem); > static inline void hmm_devmem_page_set_drvdata(struct page *page, > unsigned long data) > { > - unsigned long *drvdata = (unsigned long *)&page->pgmap; > - > - drvdata[1] = data; Well, that was ugly :) > + page->hmm_data = data; > } > > /* > @@ -535,9 +533,7 @@ static inline void hmm_devmem_page_set_drvdata(struct page *page, > */ > static inline unsigned long hmm_devmem_page_get_drvdata(const struct page *page) > { > - const unsigned long *drvdata = (const unsigned long *)&page->pgmap; > - > - return drvdata[1]; > + return page->hmm_data; > } > > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 5a519279dcd5..fa05e6ca31ed 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -150,11 +150,15 @@ struct page { > /** @rcu_head: You can use this to free a page by RCU. */ > struct rcu_head rcu_head; > > - /** > - * @pgmap: For ZONE_DEVICE pages, this points to the hosting > - * device page map. > - */ > - struct dev_pagemap *pgmap; > + struct { > + /** > + * @pgmap: For ZONE_DEVICE pages, this points to the > + * hosting device page map. > + */ > + struct dev_pagemap *pgmap; > + unsigned long hmm_data; > + unsigned long _zd_pad_1; /* uses mapping */ > + }; Maybe move this above rcu_head and make the comments look more like for the other union variants? > }; > > union { /* This union is 4 bytes in size. */ >
On 05/15/2018 11:32 AM, Vlastimil Babka wrote: >> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h >> index 5a519279dcd5..fa05e6ca31ed 100644 >> --- a/include/linux/mm_types.h >> +++ b/include/linux/mm_types.h >> @@ -150,11 +150,15 @@ struct page { >> /** @rcu_head: You can use this to free a page by RCU. */ >> struct rcu_head rcu_head; >> >> - /** >> - * @pgmap: For ZONE_DEVICE pages, this points to the hosting >> - * device page map. >> - */ >> - struct dev_pagemap *pgmap; >> + struct { >> + /** >> + * @pgmap: For ZONE_DEVICE pages, this points to the >> + * hosting device page map. >> + */ >> + struct dev_pagemap *pgmap; >> + unsigned long hmm_data; >> + unsigned long _zd_pad_1; /* uses mapping */ >> + }; > > Maybe move this above rcu_head and make the comments look more like for > the other union variants? With that you can add my acked-by as well, thanks. > >> }; >> >> union { /* This union is 4 bytes in size. */ >> >
diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 39988924de3a..91c1b2dccbbb 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -522,9 +522,7 @@ void hmm_devmem_remove(struct hmm_devmem *devmem); static inline void hmm_devmem_page_set_drvdata(struct page *page, unsigned long data) { - unsigned long *drvdata = (unsigned long *)&page->pgmap; - - drvdata[1] = data; + page->hmm_data = data; } /* @@ -535,9 +533,7 @@ static inline void hmm_devmem_page_set_drvdata(struct page *page, */ static inline unsigned long hmm_devmem_page_get_drvdata(const struct page *page) { - const unsigned long *drvdata = (const unsigned long *)&page->pgmap; - - return drvdata[1]; + return page->hmm_data; } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5a519279dcd5..fa05e6ca31ed 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -150,11 +150,15 @@ struct page { /** @rcu_head: You can use this to free a page by RCU. */ struct rcu_head rcu_head; - /** - * @pgmap: For ZONE_DEVICE pages, this points to the hosting - * device page map. - */ - struct dev_pagemap *pgmap; + struct { + /** + * @pgmap: For ZONE_DEVICE pages, this points to the + * hosting device page map. + */ + struct dev_pagemap *pgmap; + unsigned long hmm_data; + unsigned long _zd_pad_1; /* uses mapping */ + }; }; union { /* This union is 4 bytes in size. */