| Message ID | 161052334425.1805594.17861842381807251887.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: Fix pfn_to_online_page() with respect to ZONE_DEVICE | expand |
On 13.01.21 08:35, Dan Williams wrote: > Given 'struct dev_pagemap' spans both data pages and metadata pages be > careful to consult the altmap if present to delineate metadata. In fact > the pfn_first() helper already identifies the first valid data pfn, so > export that helper for other code paths via pgmap_pfn_valid(). > > Other usage of get_dev_pagemap() are not a concern because those are > operating on known data pfns having been looking up by get_user_pages(). > I.e. metadata pfns are never user mapped. > > Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Reported-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com> > --- > include/linux/memremap.h | 6 ++++++ > mm/memory-failure.c | 6 ++++++ > mm/memremap.c | 15 +++++++++++++++ > 3 files changed, 27 insertions(+) > > diff --git a/include/linux/memremap.h b/include/linux/memremap.h > index 79c49e7f5c30..f5b464daeeca 100644 > --- a/include/linux/memremap.h > +++ b/include/linux/memremap.h > @@ -137,6 +137,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); > void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); > struct dev_pagemap *get_dev_pagemap(unsigned long pfn, > struct dev_pagemap *pgmap); > +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); > > unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); > void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); > @@ -165,6 +166,11 @@ static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, > return NULL; > } > > +static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) > +{ > + return false; > +} > + > static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) > { > return 0; > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 78b173c7190c..541569cb4a99 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1308,6 +1308,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > */ > put_page(page); > > + /* device metadata space is not recoverable */ > + if (!pgmap_pfn_valid(pgmap, pfn)) { > + rc = -ENXIO; > + goto out; > + } > + > /* > * Prevent the inode from being freed while we are interrogating > * the address_space, typically this would be handled by > diff --git a/mm/memremap.c b/mm/memremap.c > index 16b2fb482da1..2455bac89506 100644 > --- a/mm/memremap.c > +++ b/mm/memremap.c > @@ -80,6 +80,21 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id) > return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); > } > > +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) > +{ > + int i; > + > + for (i = 0; i < pgmap->nr_range; i++) { > + struct range *range = &pgmap->ranges[i]; > + > + if (pfn >= PHYS_PFN(range->start) && > + pfn <= PHYS_PFN(range->end)) > + return pfn >= pfn_first(pgmap, i); > + } > + > + return false; > +} > + > static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) > { > const struct range *range = &pgmap->ranges[range_id]; > LGTM Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 79c49e7f5c30..f5b464daeeca 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -137,6 +137,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap); void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap); struct dev_pagemap *get_dev_pagemap(unsigned long pfn, struct dev_pagemap *pgmap); +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); @@ -165,6 +166,11 @@ static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn, return NULL; } +static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) +{ + return false; +} + static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) { return 0; diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 78b173c7190c..541569cb4a99 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1308,6 +1308,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, */ put_page(page); + /* device metadata space is not recoverable */ + if (!pgmap_pfn_valid(pgmap, pfn)) { + rc = -ENXIO; + goto out; + } + /* * Prevent the inode from being freed while we are interrogating * the address_space, typically this would be handled by diff --git a/mm/memremap.c b/mm/memremap.c index 16b2fb482da1..2455bac89506 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -80,6 +80,21 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id) return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); } +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) +{ + int i; + + for (i = 0; i < pgmap->nr_range; i++) { + struct range *range = &pgmap->ranges[i]; + + if (pfn >= PHYS_PFN(range->start) && + pfn <= PHYS_PFN(range->end)) + return pfn >= pfn_first(pgmap, i); + } + + return false; +} + static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) { const struct range *range = &pgmap->ranges[range_id];
Given 'struct dev_pagemap' spans both data pages and metadata pages be careful to consult the altmap if present to delineate metadata. In fact the pfn_first() helper already identifies the first valid data pfn, so export that helper for other code paths via pgmap_pfn_valid(). Other usage of get_dev_pagemap() are not a concern because those are operating on known data pfns having been looking up by get_user_pages(). I.e. metadata pfns are never user mapped. Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: David Hildenbrand <david@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- include/linux/memremap.h | 6 ++++++ mm/memory-failure.c | 6 ++++++ mm/memremap.c | 15 +++++++++++++++ 3 files changed, 27 insertions(+)