[PATCH v5 1/9] pagemap: Introduce ->memory_failure()

[Shiyang Ruan]

When memory-failure occurs, we call this function which is implemented
by each kind of devices.  For the fsdax case, pmem device driver
implements it.  Pmem device driver will find out the filesystem in which
the corrupted page located in.  And finally call filesystem handler to
deal with this error.

The filesystem will try to recover the corrupted data if necessary.

Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
---
 include/linux/memremap.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 45a79da89c5f..d96da47cc249 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -87,6 +87,15 @@ struct dev_pagemap_ops {
 	 * the page back to a CPU accessible page.
 	 */
 	vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
+
+	/*
+	 * Handle the memory failure happens on a range of pfns.  Notify the
+	 * processes who are using these pfns, and try to recover the data on
+	 * them if necessary.  The flag is finally passed to the recover
+	 * function through the whole notify routine.
+	 */
+	int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn,
+			      unsigned long nr_pfns, int flags);
 };

 #define PGMAP_ALTMAP_VALID	(1 << 0)
--
2.32.0