[PATCH v2 1/2] mm: memory-failure: Refactor add_to_kill()

[Longlong Xia <xialonglong1@xxxxxxxxxx>]

The page_address_in_vma() is used to find the user virtual address of page
in add_to_kill(), but it doesn't support ksm due to the ksm page->index
unusable, add an ksm_addr as parameter to add_to_kill(), let's the caller 
to pass it, also rename the function to __add_to_kill(), and adding
add_to_kill_anon_file() for handling anonymous pages and file pages,
adding add_to_kill_fsdax() for handling fsdax pages.

Signed-off-by: Longlong Xia <xialonglong1@xxxxxxxxxx>
Tested-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
 mm/memory-failure.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index fae9baf3be162..f5e1d80a82738 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -405,9 +405,9 @@ static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
  * page->mapping are sufficient for mapping the page back to its
  * corresponding user virtual address.
  */
-static void add_to_kill(struct task_struct *tsk, struct page *p,
-			pgoff_t fsdax_pgoff, struct vm_area_struct *vma,
-			struct list_head *to_kill)
+static void __add_to_kill(struct task_struct *tsk, struct page *p,
+			  struct vm_area_struct *vma, struct list_head *to_kill,
+			  unsigned long ksm_addr, pgoff_t fsdax_pgoff)
 {
 	struct to_kill *tk;
 
@@ -417,7 +417,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
 		return;
 	}
 
-	tk->addr = page_address_in_vma(p, vma);
+	tk->addr = ksm_addr ? ksm_addr : page_address_in_vma(p, vma);
 	if (is_zone_device_page(p)) {
 		if (fsdax_pgoff != FSDAX_INVALID_PGOFF)
 			tk->addr = vma_pgoff_address(fsdax_pgoff, 1, vma);
@@ -448,6 +448,13 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
 	list_add_tail(&tk->nd, to_kill);
 }
 
+static void add_to_kill_anon_file(struct task_struct *tsk, struct page *p,
+				  struct vm_area_struct *vma,
+				  struct list_head *to_kill)
+{
+	__add_to_kill(tsk, p, vma, to_kill, 0, FSDAX_INVALID_PGOFF);
+}
+
 /*
  * Kill the processes that have been collected earlier.
  *
@@ -573,7 +580,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
 				continue;
 			if (!page_mapped_in_vma(page, vma))
 				continue;
-			add_to_kill(t, page, FSDAX_INVALID_PGOFF, vma, to_kill);
+			add_to_kill_anon_file(t, page, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -609,8 +616,7 @@ 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, FSDAX_INVALID_PGOFF, vma,
-					    to_kill);
+				add_to_kill_anon_file(t, page, vma, to_kill);
 		}
 	}
 	read_unlock(&tasklist_lock);
@@ -618,6 +624,13 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
 }
 
 #ifdef CONFIG_FS_DAX
+static void add_to_kill_fsdax(struct task_struct *tsk, struct page *p,
+			      struct vm_area_struct *vma,
+			      struct list_head *to_kill, pgoff_t pgoff)
+{
+	__add_to_kill(tsk, p, vma, to_kill, 0, pgoff);
+}
+
 /*
  * Collect processes when the error hit a fsdax page.
  */
@@ -637,7 +650,7 @@ static void collect_procs_fsdax(struct page *page,
 			continue;
 		vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 			if (vma->vm_mm == t->mm)
-				add_to_kill(t, page, pgoff, vma, to_kill);
+				add_to_kill_fsdax(t, page, vma, to_kill, pgoff);
 		}
 	}
 	read_unlock(&tasklist_lock);
-- 
2.25.1