pagemap: remove remaining unneeded spin_lock()

Commit 025c5b2451e4 ("thp: optimize away unnecessary page table
locking") moves spin_lock() into pmd_trans_huge_lock() in order to avoid
locking unless pmd is for thp.  So this spin_lock() is a bug.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index c283832..2b9a760 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -783,7 +783,6 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 
        /* find the first VMA at or above 'addr' */
        vma = find_vma(walk->mm, addr);
-       spin_lock(&walk->mm->page_table_lock);
        if (pmd_trans_huge_lock(pmd, vma) == 1) {
                for (; addr != end; addr += PAGE_SIZE) {
                        unsigned long offset;