diff mbox series

[029/118] mm: fix memory_failure() handling of dax-namespace metadata

Message ID 20210226011708.N4sC0luia%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/118] mm: make pagecache tagged lookups return only head pages | expand

Commit Message

Andrew Morton Feb. 26, 2021, 1:17 a.m. UTC
From: Dan Williams <dan.j.williams@intel.com>
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@dwillia2-desk3.amr.corp.intel.com
Fixes: 6100e34b2526 ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memremap.h |    6 ++++++
 mm/memory-failure.c      |    6 ++++++
 mm/memremap.c            |   15 +++++++++++++++
 3 files changed, 27 insertions(+)
diff mbox series

Patch

--- a/include/linux/memremap.h~mm-fix-memory_failure-handling-of-dax-namespace-metadata
+++ a/include/linux/memremap.h
@@ -137,6 +137,7 @@  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);
@@ -165,6 +166,11 @@  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
@@ -1312,6 +1312,12 @@  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];