mm: gup: fix potential pgmap refcnt leak in __gup_device_huge()

[linux-block.git] / mm / gup.c

diff --git a/mm/gup.c b/mm/gup.c
index 9f5b9a93ae21f4dec299eace1d32e8c3d3814e8d..a10c48ef613c9377b64c76014c80a8d0b878ca4c 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2240,6 +2240,7 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr,
 {
        int nr_start = *nr;
        struct dev_pagemap *pgmap = NULL;
+       int ret = 1;
 
        do {
                struct page *page = pfn_to_page(pfn);
@@ -2247,21 +2248,22 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr,
                pgmap = get_dev_pagemap(pfn, pgmap);
                if (unlikely(!pgmap)) {
                        undo_dev_pagemap(nr, nr_start, flags, pages);
-                       return 0;
+                       ret = 0;
+                       break;
                }
                SetPageReferenced(page);
                pages[*nr] = page;
                if (unlikely(!try_grab_page(page, flags))) {
                        undo_dev_pagemap(nr, nr_start, flags, pages);
-                       return 0;
+                       ret = 0;
+                       break;
                }
                (*nr)++;
                pfn++;
        } while (addr += PAGE_SIZE, addr != end);
 
-       if (pgmap)
-               put_dev_pagemap(pgmap);
-       return 1;
+       put_dev_pagemap(pgmap);
+       return ret;
 }
 
 static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,