[SCSI] sg: fix a bug in st_map_user_pages failure path

sg's st_map_user_pages is modelled on an earlier version of st's
sgl_map_user_pages, and has the same bug: if get_user_pages got some but
not all of the pages, then those got were released, but the positive res
code returned implied that they were still to be freed.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 6de7ff9faf2d..b55c2a8a547c 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1860,9 +1860,11 @@ st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
            unlock_page(pages[j]); */
         res = 0;
  out_unmap:
-        if (res > 0)
+        if (res > 0) {
                 for (j=0; j < res; j++)
                         page_cache_release(pages[j]);
+                res = 0;
+        }
         kfree(pages);
         return res;
 }