diff mbox series

[050/262] mm/gup: further simplify __gup_device_huge()

Message ID 20211105203716.qKGfFlN1h%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/262] scripts/spelling.txt: add more spellings to spelling.txt | expand

Commit Message

Andrew Morton Nov. 5, 2021, 8:37 p.m. UTC 
From: John Hubbard <jhubbard@nvidia.com>
Subject: mm/gup: further simplify __gup_device_huge()

commit 6401c4eb57f9 ("mm: gup: fix potential pgmap refcnt leak in
__gup_device_huge()") simplified the return paths, but didn't go quite far
enough, as discussed in [1].

Remove the "ret" variable entirely, because there is enough information
already available to provide the return value.

[1] https://lore.kernel.org/r/CAHk-=wgQTRX=5SkCmS+zfmpqubGHGJvXX_HgnPG8JSpHKHBMeg@mail.gmail.com

Link: https://lkml.kernel.org/r/20210904004224.86391-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
diff mbox series

Patch

--- a/mm/gup.c~mm-gup-further-simplify-__gup_device_huge
+++ a/mm/gup.c
@@ -2228,7 +2228,6 @@  static int __gup_device_huge(unsigned lo
 {
 	int nr_start = *nr;
 	struct dev_pagemap *pgmap = NULL;
-	int ret = 1;
 
 	do {
 		struct page *page = pfn_to_page(pfn);
@@ -2236,14 +2235,12 @@  static int __gup_device_huge(unsigned lo
 		pgmap = get_dev_pagemap(pfn, pgmap);
 		if (unlikely(!pgmap)) {
 			undo_dev_pagemap(nr, nr_start, flags, pages);
-			ret = 0;
 			break;
 		}
 		SetPageReferenced(page);
 		pages[*nr] = page;
 		if (unlikely(!try_grab_page(page, flags))) {
 			undo_dev_pagemap(nr, nr_start, flags, pages);
-			ret = 0;
 			break;
 		}
 		(*nr)++;
@@ -2251,7 +2248,7 @@  static int __gup_device_huge(unsigned lo
 	} while (addr += PAGE_SIZE, addr != end);
 
 	put_dev_pagemap(pgmap);
-	return ret;
+	return addr == end;
 }
 
 static int __gup_device_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,