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authorMichael S. Tsirkin <mst@redhat.com>2018-04-13 15:35:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-13 17:10:27 -0700
commitd081107867b85cc7454b9d4f5aea47f65bcf06d1 (patch)
tree4cd38640b68f5b53262a2a1e354e3c6efc131103 /arch/sh
parentc61611f70958d86f659bca25c02ae69413747a8d (diff)
downloadlinux-d081107867b85cc7454b9d4f5aea47f65bcf06d1.tar.gz
mm/gup.c: document return value
__get_user_pages_fast handles errors differently from
get_user_pages_fast: the former always returns the number of pages
pinned, the later might return a negative error code.

Link: http://lkml.kernel.org/r/1522962072-182137-6-git-send-email-mst@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/mm/gup.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/sh/mm/gup.c b/arch/sh/mm/gup.c
index 8045b5bb7075..56c86ca98ecf 100644
--- a/arch/sh/mm/gup.c
+++ b/arch/sh/mm/gup.c
@@ -160,6 +160,8 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
 /*
  * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
  * back to the regular GUP.
+ * Note a difference with get_user_pages_fast: this always returns the
+ * number of pages pinned, 0 if no pages were pinned.
  */
 int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
 			  struct page **pages)