mm/memory-failure.c clean up around tk pre-allocation

add_to_kill() expects the first 'tk' to be pre-allocated, it makes
subsequent allocations on need basis, this makes the code a bit
difficult to read.

Move all the allocation internal to add_to_kill() and drop the **tk
argument.

Link: http://lkml.kernel.org/r/1565112345-28754-2-git-send-email-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 3151c87..05c8c6d 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -303,25 +303,19 @@ 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.
- * TBD would GFP_NOIO be enough?
  */
 static void add_to_kill(struct task_struct *tsk, struct page *p,
                       struct vm_area_struct *vma,
-                      struct list_head *to_kill,
-                      struct to_kill **tkc)
+                      struct list_head *to_kill)
 {
        struct to_kill *tk;
 
-       if (*tkc) {
-               tk = *tkc;
-               *tkc = NULL;
-       } else {
-               tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
-               if (!tk) {
-                       pr_err("Memory failure: Out of memory while machine check handling\n");
-                       return;
-               }
+       tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
+       if (!tk) {
+               pr_err("Memory failure: Out of memory while machine check handling\n");
+               return;
        }
+
        tk->addr = page_address_in_vma(p, vma);
        if (is_zone_device_page(p))
                tk->size_shift = dev_pagemap_mapping_shift(p, vma);
@@ -345,6 +339,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
                kfree(tk);
                return;
        }
+
        get_task_struct(tsk);
        tk->tsk = tsk;
        list_add_tail(&tk->nd, to_kill);
@@ -436,7 +431,7 @@ static struct task_struct *task_early_kill(struct task_struct *tsk,
  * Collect processes when the error hit an anonymous page.
  */
 static void collect_procs_anon(struct page *page, struct list_head *to_kill,
-                             struct to_kill **tkc, int force_early)
+                               int force_early)
 {
        struct vm_area_struct *vma;
        struct task_struct *tsk;
@@ -461,7 +456,7 @@ 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, tkc);
+                               add_to_kill(t, page, vma, to_kill);
                }
        }
        read_unlock(&tasklist_lock);
@@ -472,7 +467,7 @@ 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,
-                             struct to_kill **tkc, int force_early)
+                               int force_early)
 {
        struct vm_area_struct *vma;
        struct task_struct *tsk;
@@ -496,7 +491,7 @@ 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, tkc);
+                               add_to_kill(t, page, vma, to_kill);
                }
        }
        read_unlock(&tasklist_lock);
@@ -505,26 +500,17 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
 
 /*
  * Collect the processes who have the corrupted page mapped to kill.
- * This is done in two steps for locking reasons.
- * First preallocate one tokill structure outside the spin locks,
- * so that we can kill at least one process reasonably reliable.
  */
 static void collect_procs(struct page *page, struct list_head *tokill,
                                int force_early)
 {
-       struct to_kill *tk;
-
        if (!page->mapping)
                return;
 
-       tk = kmalloc(sizeof(struct to_kill), GFP_NOIO);
-       if (!tk)
-               return;
        if (PageAnon(page))
-               collect_procs_anon(page, tokill, &tk, force_early);
+               collect_procs_anon(page, tokill, force_early);
        else
-               collect_procs_file(page, tokill, &tk, force_early);
-       kfree(tk);
+               collect_procs_file(page, tokill, force_early);
 }
 
 static const char *action_name[] = {