The patch titled
Subject: mm: fix memory_failure() handling of dax-namespace metadata
has been added to the -mm tree. Its filename is
mm-fix-memory_failure-handling-of-dax-namespace-metadata.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-fix-memory_failure-handling-of-dax-namespace-metadata.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-memory_failure-handling-of-dax-namespace-metadata.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm: fix memory_failure() handling of dax-namespace metadata
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 looked up by get_user_pages().
I.e. metadata pfns are never user mapped.
Link: https://lkml.kernel.org/r/161058501758.1840162.4239831989762604527.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 6100e34b2526 ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memremap.h | 6 ++++++
mm/memory-failure.c | 6 ++++++
mm/memremap.c | 15 +++++++++++++++
3 files changed, 27 insertions(+)
--- a/include/linux/memremap.h~mm-fix-memory_failure-handling-of-dax-namespace-metadata
+++ a/include/linux/memremap.h
@@ -138,6 +138,7 @@ void *devm_memremap_pages(struct device
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);
@@ -171,6 +172,11 @@ static inline struct dev_pagemap *get_de
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;
--- a/mm/memory-failure.c~mm-fix-memory_failure-handling-of-dax-namespace-metadata
+++ a/mm/memory-failure.c
@@ -1308,6 +1308,12 @@ static int memory_failure_dev_pagemap(un
*/
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
--- a/mm/memremap.c~mm-fix-memory_failure-handling-of-dax-namespace-metadata
+++ a/mm/memremap.c
@@ -80,6 +80,21 @@ static unsigned long pfn_first(struct de
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];
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
mm-fix-page-reference-leak-in-soft_offline_page.patch
mm-move-pfn_to_online_page-out-of-line.patch
mm-teach-pfn_to_online_page-to-consider-subsection-validity.patch
mm-teach-pfn_to_online_page-about-zone_device-section-collisions.patch
mm-fix-memory_failure-handling-of-dax-namespace-metadata.patch
