diff mbox series

[v3,05/11] mm, fsdax: Refactor memory-failure handler for dax mapping

Message ID 20210208105530.3072869-6-ruansy.fnst@cn.fujitsu.com (mailing list archive)
State New
Headers show
Series fsdax: introduce fs query to support reflink | expand

Commit Message

Ruan Shiyang Feb. 8, 2021, 10:55 a.m. UTC
The current memory_failure_dev_pagemap() can only handle single-mapped
dax page for fsdax mode.  The dax page could be mapped by multiple files
and offsets if we let reflink feature & fsdax mode work together.  So,
we refactor current implementation to support handle memory failure on
each file and offset.

Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
---
 fs/dax.c            | 21 ++++++++++
 include/linux/dax.h |  1 +
 include/linux/mm.h  |  9 +++++
 mm/memory-failure.c | 98 ++++++++++++++++++++++++++++++++++-----------
 4 files changed, 105 insertions(+), 24 deletions(-)

Comments

Christoph Hellwig Feb. 10, 2021, 1:33 p.m. UTC | #1
> +extern int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags);

No nee for the extern, please avoid the overly long line.

> @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p)
>  	if (PageSlab(p))
>  		return -EINVAL;
>  
> +	if (pfn_valid(page_to_pfn(p))) {
> +		if (is_device_fsdax_page(p))
> +			return 0;
> +		else
> +			return -EINVAL;
> +	}
> +

This looks odd.  For one there is no need for an else after a return.
But more importantly page_mapping() as called below pretty much assumes
a valid PFN, so something is fishy in this function.

> +	if (is_zone_device_page(p)) {
> +		if (is_device_fsdax_page(p))
> +			tk->addr = vma->vm_start +
> +					((pgoff - vma->vm_pgoff) << PAGE_SHIFT);

The arithmetics here scream for a common helper, I suspect there might
be other places that could use the same helper.

> +int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags)

Overly long line.  Also the naming scheme with the mf_ seems rather
unusual. Maybe dax_kill_mapping_procs?  Also please add a kerneldoc
comment describing the function given that it exported.
Ruan Shiyang Feb. 17, 2021, 2:56 a.m. UTC | #2
On 2021/2/10 下午9:33, Christoph Hellwig wrote:
>> +extern int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags);
> 
> No nee for the extern, please avoid the overly long line.

OK.

I'd like to confirm one thing...  I have checked all of this patchset by 
checkpatch.pl and it did not report the overly long line warning.  So, I 
should still obey the rule of 80 chars one line?

> 
>> @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p)
>>   	if (PageSlab(p))
>>   		return -EINVAL;
>>   
>> +	if (pfn_valid(page_to_pfn(p))) {
>> +		if (is_device_fsdax_page(p))
>> +			return 0;
>> +		else
>> +			return -EINVAL;
>> +	}
>> +
> 
> This looks odd.  For one there is no need for an else after a return.
> But more importantly page_mapping() as called below pretty much assumes
> a valid PFN, so something is fishy in this function.

Yes, a mistake here.  I'll fix it.

> 
>> +	if (is_zone_device_page(p)) {
>> +		if (is_device_fsdax_page(p))
>> +			tk->addr = vma->vm_start +
>> +					((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
> 
> The arithmetics here scream for a common helper, I suspect there might
> be other places that could use the same helper.
> 
>> +int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags)
> 
> Overly long line.  Also the naming scheme with the mf_ seems rather
> unusual. Maybe dax_kill_mapping_procs?  Also please add a kerneldoc
> comment describing the function given that it exported.
> 

OK.  Thanks for your guidance.


--
Thanks,
Ruan Shiyang.

>
Christoph Hellwig Feb. 18, 2021, 8:32 a.m. UTC | #3
On Wed, Feb 17, 2021 at 10:56:11AM +0800, Ruan Shiyang wrote:
> I'd like to confirm one thing...  I have checked all of this patchset by 
> checkpatch.pl and it did not report the overly long line warning.  So, I 
> should still obey the rule of 80 chars one line?

checkpatch.pl is completely broken, I would not rely on it.

Here is the quote from the coding style document:

"The preferred limit on the length of a single line is 80 columns.

Statements longer than 80 columns should be broken into sensible chunks,
unless exceeding 80 columns significantly increases readability and does
not hide information."
Ruan Shiyang Feb. 18, 2021, 8:59 a.m. UTC | #4
On 2021/2/18 下午4:32, Christoph Hellwig wrote:
> On Wed, Feb 17, 2021 at 10:56:11AM +0800, Ruan Shiyang wrote:
>> I'd like to confirm one thing...  I have checked all of this patchset by
>> checkpatch.pl and it did not report the overly long line warning.  So, I
>> should still obey the rule of 80 chars one line?
> 
> checkpatch.pl is completely broken, I would not rely on it.
> 
> Here is the quote from the coding style document:
> 
> "The preferred limit on the length of a single line is 80 columns.
> 
> Statements longer than 80 columns should be broken into sensible chunks,
> unless exceeding 80 columns significantly increases readability and does
> not hide information."
> 

OK.  Got it.  Thank you.


--
Ruan Shiyang.
>
zhongjiang-ali March 16, 2021, 3:21 a.m. UTC | #5
On 2021/2/8 6:55 下午, Shiyang Ruan wrote:
> The current memory_failure_dev_pagemap() can only handle single-mapped
> dax page for fsdax mode.  The dax page could be mapped by multiple files
> and offsets if we let reflink feature & fsdax mode work together.  So,
> we refactor current implementation to support handle memory failure on
> each file and offset.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
> ---
>   fs/dax.c            | 21 ++++++++++
>   include/linux/dax.h |  1 +
>   include/linux/mm.h  |  9 +++++
>   mm/memory-failure.c | 98 ++++++++++++++++++++++++++++++++++-----------
>   4 files changed, 105 insertions(+), 24 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 26d5dcd2d69e..c64c3a0e76a6 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -378,6 +378,27 @@ static struct page *dax_busy_page(void *entry)
>   	return NULL;
>   }
>   
> +/*
> + * dax_load_pfn - Load pfn of the DAX entry corresponding to a page
> + * @mapping: The file whose entry we want to load
> + * @index:   The offset where the DAX entry located in
> + *
> + * Return:   pfn of the DAX entry
> + */
> +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index)
> +{
> +	XA_STATE(xas, &mapping->i_pages, index);
> +	void *entry;
> +	unsigned long pfn;
> +
> +	xas_lock_irq(&xas);
> +	entry = xas_load(&xas);
> +	pfn = dax_to_pfn(entry);
> +	xas_unlock_irq(&xas);
> +
> +	return pfn;
> +}
> +
>   /*
>    * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page
>    * @page: The page whose entry we want to lock
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index b52f084aa643..89e56ceeffc7 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -150,6 +150,7 @@ int dax_writeback_mapping_range(struct address_space *mapping,
>   
>   struct page *dax_layout_busy_page(struct address_space *mapping);
>   struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
> +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index);
>   dax_entry_t dax_lock_page(struct page *page);
>   void dax_unlock_page(struct page *page, dax_entry_t cookie);
>   #else
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ecdf8a8cd6ae..ab52bc633d84 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1157,6 +1157,14 @@ static inline bool is_device_private_page(const struct page *page)
>   		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
>   }
>   
> +static inline bool is_device_fsdax_page(const struct page *page)
> +{
> +	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> +		IS_ENABLED(CONFIG_FS_DAX) &&
> +		is_zone_device_page(page) &&
> +		page->pgmap->type == MEMORY_DEVICE_FS_DAX;
> +}
> +
>   static inline bool is_pci_p2pdma_page(const struct page *page)
>   {
>   	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
> @@ -3045,6 +3053,7 @@ enum mf_flags {
>   	MF_MUST_KILL = 1 << 2,
>   	MF_SOFT_OFFLINE = 1 << 3,
>   };
> +extern int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags);
>   extern int memory_failure(unsigned long pfn, int flags);
>   extern void memory_failure_queue(unsigned long pfn, int flags);
>   extern void memory_failure_queue_kick(int cpu);
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index e9481632fcd1..158fe0c8e602 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -56,6 +56,7 @@
>   #include <linux/kfifo.h>
>   #include <linux/ratelimit.h>
>   #include <linux/page-isolation.h>
> +#include <linux/dax.h>
>   #include "internal.h"
>   #include "ras/ras_event.h"
>   
> @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p)
>   	if (PageSlab(p))
>   		return -EINVAL;
>   
> +	if (pfn_valid(page_to_pfn(p))) {
> +		if (is_device_fsdax_page(p))
> +			return 0;
> +		else
> +			return -EINVAL;
> +	}
> +
>   	mapping = page_mapping(p);
>   	if (mapping == NULL || mapping->host == NULL)
>   		return -EINVAL;
> @@ -286,10 +294,9 @@ void shake_page(struct page *p, int access)
>   }
>   EXPORT_SYMBOL_GPL(shake_page);
>   
> -static unsigned long dev_pagemap_mapping_shift(struct page *page,
> -		struct vm_area_struct *vma)
> +static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
> +					       unsigned long address)
>   {
> -	unsigned long address = vma_address(page, vma);
>   	pgd_t *pgd;
>   	p4d_t *p4d;
>   	pud_t *pud;
> @@ -329,9 +336,8 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page,
>    * Schedule a process for later kill.
>    * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
>    */
> -static void add_to_kill(struct task_struct *tsk, struct page *p,
> -		       struct vm_area_struct *vma,
> -		       struct list_head *to_kill)
> +static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff,
> +			struct vm_area_struct *vma, struct list_head *to_kill)
>   {
>   	struct to_kill *tk;
>   
> @@ -342,9 +348,12 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
>   	}
>   
>   	tk->addr = page_address_in_vma(p, vma);
> -	if (is_zone_device_page(p))
> -		tk->size_shift = dev_pagemap_mapping_shift(p, vma);
> -	else
> +	if (is_zone_device_page(p)) {
> +		if (is_device_fsdax_page(p))
> +			tk->addr = vma->vm_start +
> +					((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
> +		tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr);
> +	} else
>   		tk->size_shift = page_shift(compound_head(p));
>   
>   	/*
> @@ -492,7 +501,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
>   			if (!page_mapped_in_vma(page, vma))
>   				continue;
>   			if (vma->vm_mm == t->mm)
> -				add_to_kill(t, page, vma, to_kill);
> +				add_to_kill(t, page, 0, vma, to_kill);
>   		}
>   	}
>   	read_unlock(&tasklist_lock);
> @@ -502,24 +511,19 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
>   /*
>    * Collect processes when the error hit a file mapped page.
>    */
> -static void collect_procs_file(struct page *page, struct list_head *to_kill,
> -				int force_early)
> +static void collect_procs_file(struct page *page, struct address_space *mapping,
> +		pgoff_t pgoff, struct list_head *to_kill, int force_early)
>   {
>   	struct vm_area_struct *vma;
>   	struct task_struct *tsk;
> -	struct address_space *mapping = page->mapping;
> -	pgoff_t pgoff;
>   
>   	i_mmap_lock_read(mapping);
>   	read_lock(&tasklist_lock);
> -	pgoff = page_to_pgoff(page);
>   	for_each_process(tsk) {
>   		struct task_struct *t = task_early_kill(tsk, force_early);
> -
>   		if (!t)
>   			continue;
> -		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
> -				      pgoff) {
> +		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
>   			/*
>   			 * Send early kill signal to tasks where a vma covers
>   			 * the page but the corrupted page is not necessarily
> @@ -528,7 +532,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
>   			 * to be informed of all such data corruptions.
>   			 */
>   			if (vma->vm_mm == t->mm)
> -				add_to_kill(t, page, vma, to_kill);
> +				add_to_kill(t, page, pgoff, vma, to_kill);
>   		}
>   	}
>   	read_unlock(&tasklist_lock);
> @@ -547,7 +551,8 @@ static void collect_procs(struct page *page, struct list_head *tokill,
>   	if (PageAnon(page))
>   		collect_procs_anon(page, tokill, force_early);
>   	else
> -		collect_procs_file(page, tokill, force_early);
> +		collect_procs_file(page, page_mapping(page), page_to_pgoff(page),
> +				   tokill, force_early);
>   }
>   
>   static const char *action_name[] = {
> @@ -1214,6 +1219,50 @@ static int try_to_split_thp_page(struct page *page, const char *msg)
>   	return 0;
>   }
>   
> +int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags)
> +{
> +	const bool unmap_success = true;
> +	unsigned long pfn, size = 0;
> +	struct to_kill *tk;
> +	LIST_HEAD(to_kill);
> +	int rc = -EBUSY;
> +	loff_t start;
> +
> +	/* load the pfn of the dax mapping file */
> +	pfn = dax_load_pfn(mapping, index);
> +	if (!pfn)
> +		return rc;
> +	/*
> +	 * Unlike System-RAM there is no possibility to swap in a
> +	 * different physical page at a given virtual address, so all
> +	 * userspace consumption of ZONE_DEVICE memory necessitates
> +	 * SIGBUS (i.e. MF_MUST_KILL)
> +	 */
> +	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;

MF_ACTION_REQUIRED only kill the current execution context. A page can be shared
when reflink file be mapped by different process. We can not kill all process
shared the page.  Other process still can access the posioned page ?

Thanks,
zhong jiang

> +	collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill,
> +			   flags & MF_ACTION_REQUIRED);
> +
> +	list_for_each_entry(tk, &to_kill, nd)
> +		if (tk->size_shift)
> +			size = max(size, 1UL << tk->size_shift);
> +	if (size) {
> +		/*
> +		 * Unmap the largest mapping to avoid breaking up
> +		 * device-dax mappings which are constant size. The
> +		 * actual size of the mapping being torn down is
> +		 * communicated in siginfo, see kill_proc()
> +		 */
> +		start = (index << PAGE_SHIFT) & ~(size - 1);
> +		unmap_mapping_range(mapping, start, start + size, 0);
> +	}
> +
> +	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success,
> +		   pfn, flags);
> +	rc = 0;
> +	return rc;
> +}
> +EXPORT_SYMBOL_GPL(mf_dax_mapping_kill_procs);
> +
>   static int memory_failure_hugetlb(unsigned long pfn, int flags)
>   {
>   	struct page *p = pfn_to_page(pfn);
> @@ -1297,7 +1346,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
>   	const bool unmap_success = true;
>   	unsigned long size = 0;
>   	struct to_kill *tk;
> -	LIST_HEAD(tokill);
> +	LIST_HEAD(to_kill);
>   	int rc = -EBUSY;
>   	loff_t start;
>   	dax_entry_t cookie;
> @@ -1345,9 +1394,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
>   	 * SIGBUS (i.e. MF_MUST_KILL)
>   	 */
>   	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
> -	collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
> +	collect_procs_file(page, page->mapping, page->index, &to_kill,
> +			   flags & MF_ACTION_REQUIRED);
>   
> -	list_for_each_entry(tk, &tokill, nd)
> +	list_for_each_entry(tk, &to_kill, nd)
>   		if (tk->size_shift)
>   			size = max(size, 1UL << tk->size_shift);
>   	if (size) {
> @@ -1360,7 +1410,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
>   		start = (page->index << PAGE_SHIFT) & ~(size - 1);
>   		unmap_mapping_range(page->mapping, start, start + size, 0);
>   	}
> -	kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
> +	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
>   	rc = 0;
>   unlock:
>   	dax_unlock_page(page, cookie);
ruansy.fnst@fujitsu.com March 17, 2021, 3:46 a.m. UTC | #6
> -----Original Message-----
> From: zhong jiang <zhongjiang-ali@linux.alibaba.com>
> Subject: Re: [PATCH v3 05/11] mm, fsdax: Refactor memory-failure handler for
> dax mapping
> 
> > +int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t
> > +index, int flags) {
> > +	const bool unmap_success = true;
> > +	unsigned long pfn, size = 0;
> > +	struct to_kill *tk;
> > +	LIST_HEAD(to_kill);
> > +	int rc = -EBUSY;
> > +	loff_t start;
> > +
> > +	/* load the pfn of the dax mapping file */
> > +	pfn = dax_load_pfn(mapping, index);
> > +	if (!pfn)
> > +		return rc;
> > +	/*
> > +	 * Unlike System-RAM there is no possibility to swap in a
> > +	 * different physical page at a given virtual address, so all
> > +	 * userspace consumption of ZONE_DEVICE memory necessitates
> > +	 * SIGBUS (i.e. MF_MUST_KILL)
> > +	 */
> > +	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
> 
> MF_ACTION_REQUIRED only kill the current execution context. A page can be
> shared when reflink file be mapped by different process. We can not kill all
> process shared the page.  Other process still can access the posioned page ?

AFAIK, the other processes will receive a SIGBUS when accessing this corrupted range.  But I didn't add a testcase for this condition.  I'll test it.  Thanks for pointing out.


--
Thanks,
Ruan Shiyang.

> 
> Thanks,
> zhong jiang
> 
> > +	collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill,
> > +			   flags & MF_ACTION_REQUIRED);
> > +
> > +	list_for_each_entry(tk, &to_kill, nd)
> > +		if (tk->size_shift)
> > +			size = max(size, 1UL << tk->size_shift);
> > +	if (size) {
> > +		/*
> > +		 * Unmap the largest mapping to avoid breaking up
> > +		 * device-dax mappings which are constant size. The
> > +		 * actual size of the mapping being torn down is
> > +		 * communicated in siginfo, see kill_proc()
> > +		 */
> > +		start = (index << PAGE_SHIFT) & ~(size - 1);
> > +		unmap_mapping_range(mapping, start, start + size, 0);
> > +	}
> > +
> > +	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success,
> > +		   pfn, flags);
> > +	rc = 0;
> > +	return rc;
> > +}
> > +EXPORT_SYMBOL_GPL(mf_dax_mapping_kill_procs);
> > +
> >   static int memory_failure_hugetlb(unsigned long pfn, int flags)
> >   {
> >   	struct page *p = pfn_to_page(pfn);
> > @@ -1297,7 +1346,7 @@ static int memory_failure_dev_pagemap(unsigned
> long pfn, int flags,
> >   	const bool unmap_success = true;
> >   	unsigned long size = 0;
> >   	struct to_kill *tk;
> > -	LIST_HEAD(tokill);
> > +	LIST_HEAD(to_kill);
> >   	int rc = -EBUSY;
> >   	loff_t start;
> >   	dax_entry_t cookie;
> > @@ -1345,9 +1394,10 @@ static int
> memory_failure_dev_pagemap(unsigned long pfn, int flags,
> >   	 * SIGBUS (i.e. MF_MUST_KILL)
> >   	 */
> >   	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
> > -	collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
> > +	collect_procs_file(page, page->mapping, page->index, &to_kill,
> > +			   flags & MF_ACTION_REQUIRED);
> >
> > -	list_for_each_entry(tk, &tokill, nd)
> > +	list_for_each_entry(tk, &to_kill, nd)
> >   		if (tk->size_shift)
> >   			size = max(size, 1UL << tk->size_shift);
> >   	if (size) {
> > @@ -1360,7 +1410,7 @@ static int memory_failure_dev_pagemap(unsigned
> long pfn, int flags,
> >   		start = (page->index << PAGE_SHIFT) & ~(size - 1);
> >   		unmap_mapping_range(page->mapping, start, start + size, 0);
> >   	}
> > -	kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
> > +	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success, pfn,
> > +flags);
> >   	rc = 0;
> >   unlock:
> >   	dax_unlock_page(page, cookie);
>
diff mbox series

Patch

diff --git a/fs/dax.c b/fs/dax.c
index 26d5dcd2d69e..c64c3a0e76a6 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -378,6 +378,27 @@  static struct page *dax_busy_page(void *entry)
 	return NULL;
 }
 
+/*
+ * dax_load_pfn - Load pfn of the DAX entry corresponding to a page
+ * @mapping: The file whose entry we want to load
+ * @index:   The offset where the DAX entry located in
+ *
+ * Return:   pfn of the DAX entry
+ */
+unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index)
+{
+	XA_STATE(xas, &mapping->i_pages, index);
+	void *entry;
+	unsigned long pfn;
+
+	xas_lock_irq(&xas);
+	entry = xas_load(&xas);
+	pfn = dax_to_pfn(entry);
+	xas_unlock_irq(&xas);
+
+	return pfn;
+}
+
 /*
  * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page
  * @page: The page whose entry we want to lock
diff --git a/include/linux/dax.h b/include/linux/dax.h
index b52f084aa643..89e56ceeffc7 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -150,6 +150,7 @@  int dax_writeback_mapping_range(struct address_space *mapping,
 
 struct page *dax_layout_busy_page(struct address_space *mapping);
 struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
+unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index);
 dax_entry_t dax_lock_page(struct page *page);
 void dax_unlock_page(struct page *page, dax_entry_t cookie);
 #else
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ecdf8a8cd6ae..ab52bc633d84 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1157,6 +1157,14 @@  static inline bool is_device_private_page(const struct page *page)
 		page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
+static inline bool is_device_fsdax_page(const struct page *page)
+{
+	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
+		IS_ENABLED(CONFIG_FS_DAX) &&
+		is_zone_device_page(page) &&
+		page->pgmap->type == MEMORY_DEVICE_FS_DAX;
+}
+
 static inline bool is_pci_p2pdma_page(const struct page *page)
 {
 	return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) &&
@@ -3045,6 +3053,7 @@  enum mf_flags {
 	MF_MUST_KILL = 1 << 2,
 	MF_SOFT_OFFLINE = 1 << 3,
 };
+extern int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags);
 extern int memory_failure(unsigned long pfn, int flags);
 extern void memory_failure_queue(unsigned long pfn, int flags);
 extern void memory_failure_queue_kick(int cpu);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e9481632fcd1..158fe0c8e602 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -56,6 +56,7 @@ 
 #include <linux/kfifo.h>
 #include <linux/ratelimit.h>
 #include <linux/page-isolation.h>
+#include <linux/dax.h>
 #include "internal.h"
 #include "ras/ras_event.h"
 
@@ -120,6 +121,13 @@  static int hwpoison_filter_dev(struct page *p)
 	if (PageSlab(p))
 		return -EINVAL;
 
+	if (pfn_valid(page_to_pfn(p))) {
+		if (is_device_fsdax_page(p))
+			return 0;
+		else
+			return -EINVAL;
+	}
+
 	mapping = page_mapping(p);
 	if (mapping == NULL || mapping->host == NULL)
 		return -EINVAL;
@@ -286,10 +294,9 @@  void shake_page(struct page *p, int access)
 }
 EXPORT_SYMBOL_GPL(shake_page);
 
-static unsigned long dev_pagemap_mapping_shift(struct page *page,
-		struct vm_area_struct *vma)
+static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
+					       unsigned long address)
 {
-	unsigned long address = vma_address(page, vma);
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
@@ -329,9 +336,8 @@  static unsigned long dev_pagemap_mapping_shift(struct page *page,
  * Schedule a process for later kill.
  * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
  */
-static void add_to_kill(struct task_struct *tsk, struct page *p,
-		       struct vm_area_struct *vma,
-		       struct list_head *to_kill)
+static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff,
+			struct vm_area_struct *vma, struct list_head *to_kill)
 {
 	struct to_kill *tk;
 
@@ -342,9 +348,12 @@  static void add_to_kill(struct task_struct *tsk, struct page *p,
 	}
 
 	tk->addr = page_address_in_vma(p, vma);
-	if (is_zone_device_page(p))
-		tk->size_shift = dev_pagemap_mapping_shift(p, vma);
-	else
+	if (is_zone_device_page(p)) {
+		if (is_device_fsdax_page(p))
+			tk->addr = vma->vm_start +
+					((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+		tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr);
+	} else
 		tk->size_shift = page_shift(compound_head(p));
 
 	/*
@@ -492,7 +501,7 @@  static void collect_procs_anon(struct page *page, struct list_head *to_kill,
 			if (!page_mapped_in_vma(page, vma))
 				continue;
 			if (vma->vm_mm == t->mm)
-				add_to_kill(t, page, vma, to_kill);
+				add_to_kill(t, page, 0, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -502,24 +511,19 @@  static void collect_procs_anon(struct page *page, struct list_head *to_kill,
 /*
  * Collect processes when the error hit a file mapped page.
  */
-static void collect_procs_file(struct page *page, struct list_head *to_kill,
-				int force_early)
+static void collect_procs_file(struct page *page, struct address_space *mapping,
+		pgoff_t pgoff, struct list_head *to_kill, int force_early)
 {
 	struct vm_area_struct *vma;
 	struct task_struct *tsk;
-	struct address_space *mapping = page->mapping;
-	pgoff_t pgoff;
 
 	i_mmap_lock_read(mapping);
 	read_lock(&tasklist_lock);
-	pgoff = page_to_pgoff(page);
 	for_each_process(tsk) {
 		struct task_struct *t = task_early_kill(tsk, force_early);
-
 		if (!t)
 			continue;
-		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
-				      pgoff) {
+		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 			/*
 			 * Send early kill signal to tasks where a vma covers
 			 * the page but the corrupted page is not necessarily
@@ -528,7 +532,7 @@  static void collect_procs_file(struct page *page, struct list_head *to_kill,
 			 * to be informed of all such data corruptions.
 			 */
 			if (vma->vm_mm == t->mm)
-				add_to_kill(t, page, vma, to_kill);
+				add_to_kill(t, page, pgoff, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -547,7 +551,8 @@  static void collect_procs(struct page *page, struct list_head *tokill,
 	if (PageAnon(page))
 		collect_procs_anon(page, tokill, force_early);
 	else
-		collect_procs_file(page, tokill, force_early);
+		collect_procs_file(page, page_mapping(page), page_to_pgoff(page),
+				   tokill, force_early);
 }
 
 static const char *action_name[] = {
@@ -1214,6 +1219,50 @@  static int try_to_split_thp_page(struct page *page, const char *msg)
 	return 0;
 }
 
+int mf_dax_mapping_kill_procs(struct address_space *mapping, pgoff_t index, int flags)
+{
+	const bool unmap_success = true;
+	unsigned long pfn, size = 0;
+	struct to_kill *tk;
+	LIST_HEAD(to_kill);
+	int rc = -EBUSY;
+	loff_t start;
+
+	/* load the pfn of the dax mapping file */
+	pfn = dax_load_pfn(mapping, index);
+	if (!pfn)
+		return rc;
+	/*
+	 * Unlike System-RAM there is no possibility to swap in a
+	 * different physical page at a given virtual address, so all
+	 * userspace consumption of ZONE_DEVICE memory necessitates
+	 * SIGBUS (i.e. MF_MUST_KILL)
+	 */
+	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
+	collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill,
+			   flags & MF_ACTION_REQUIRED);
+
+	list_for_each_entry(tk, &to_kill, nd)
+		if (tk->size_shift)
+			size = max(size, 1UL << tk->size_shift);
+	if (size) {
+		/*
+		 * Unmap the largest mapping to avoid breaking up
+		 * device-dax mappings which are constant size. The
+		 * actual size of the mapping being torn down is
+		 * communicated in siginfo, see kill_proc()
+		 */
+		start = (index << PAGE_SHIFT) & ~(size - 1);
+		unmap_mapping_range(mapping, start, start + size, 0);
+	}
+
+	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success,
+		   pfn, flags);
+	rc = 0;
+	return rc;
+}
+EXPORT_SYMBOL_GPL(mf_dax_mapping_kill_procs);
+
 static int memory_failure_hugetlb(unsigned long pfn, int flags)
 {
 	struct page *p = pfn_to_page(pfn);
@@ -1297,7 +1346,7 @@  static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 	const bool unmap_success = true;
 	unsigned long size = 0;
 	struct to_kill *tk;
-	LIST_HEAD(tokill);
+	LIST_HEAD(to_kill);
 	int rc = -EBUSY;
 	loff_t start;
 	dax_entry_t cookie;
@@ -1345,9 +1394,10 @@  static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 	 * SIGBUS (i.e. MF_MUST_KILL)
 	 */
 	flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;
-	collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED);
+	collect_procs_file(page, page->mapping, page->index, &to_kill,
+			   flags & MF_ACTION_REQUIRED);
 
-	list_for_each_entry(tk, &tokill, nd)
+	list_for_each_entry(tk, &to_kill, nd)
 		if (tk->size_shift)
 			size = max(size, 1UL << tk->size_shift);
 	if (size) {
@@ -1360,7 +1410,7 @@  static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
 		start = (page->index << PAGE_SHIFT) & ~(size - 1);
 		unmap_mapping_range(page->mapping, start, start + size, 0);
 	}
-	kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
+	kill_procs(&to_kill, flags & MF_MUST_KILL, !unmap_success, pfn, flags);
 	rc = 0;
 unlock:
 	dax_unlock_page(page, cookie);