mm/madvise: fix madvise_[un]lock() issue

We are asymmetric in our locking/unlocking in the case of memory failure
madvise() behaviour options, correct this and abstract the memory failure
check.

Link: https://lkml.kernel.org/r/2f448f7b-1da7-4099-aa9e-0179d47fde40@lucifer.local
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: "Lai, Yi" <yi1.lai@linux.intel.com>
Closes: https://lore.kernel.org/Z6rgiVp7221r4JZ5@ly-workstation
Reviewed-by: SeongJae Park <sj@kernel.org>
Tested-by: SeongJae Park <sj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Liam R. Howlett <howlett@gmail.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/madvise.c b/mm/madvise.c
index c8d4a4978920df0e7435dbf07d7e5862266c2935..6dd906828001ddd796db7fe4d5584b720bfe7dbe 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1575,14 +1575,29 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
 }
 #endif /* CONFIG_ANON_VMA_NAME */
 
-static int madvise_lock(struct mm_struct *mm, int behavior)
-{
-
 #ifdef CONFIG_MEMORY_FAILURE
-       if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
-               return 0;
+static bool is_memory_failure(int behavior)
+{
+       switch (behavior) {
+       case MADV_HWPOISON:
+       case MADV_SOFT_OFFLINE:
+               return true;
+       default:
+               return false;
+       }
+}
+#else
+static bool is_memory_failure(int behavior)
+{
+       return false;
+}
 #endif
 
+static int madvise_lock(struct mm_struct *mm, int behavior)
+{
+       if (is_memory_failure(behavior))
+           return 0;
+
        if (madvise_need_mmap_write(behavior)) {
                if (mmap_write_lock_killable(mm))
                        return -EINTR;
@@ -1590,11 +1605,13 @@ static int madvise_lock(struct mm_struct *mm, int behavior)
                mmap_read_lock(mm);
        }
        return 0;
-
 }
 
 static void madvise_unlock(struct mm_struct *mm, int behavior)
 {
+       if (is_memory_failure(behavior))
+           return;
+
        if (madvise_need_mmap_write(behavior))
                mmap_write_unlock(mm);
        else