[PATCH] block/bio: Do not zero user pages

[Keith Busch]

We don't need to zero fill the bio if not using kernel allocated pages.

Fixes: f3587d76da05 ("block: Clear kernel memory before copying to user") # 
v4.20-rc2
Reported-by: Todd Aiken <tai...@mvtech.ca>
Cc: Laurence Oberman <lober...@redhat.com>
Cc: sta...@vger.kernel.org
Cc: Bart Van Assche <bvanass...@acm.org>
Signed-off-by: Keith Busch <keith.bu...@intel.com>
---
 block/bio.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index c4ef8aa46452..55a5386fd431 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1262,7 +1262,8 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
                if (ret)
                        goto cleanup;
        } else {
-               zero_fill_bio(bio);
+               if (bmd->is_our_pages)
+                       zero_fill_bio(bio);
                iov_iter_advance(iter, bio->bi_iter.bi_size);
        }
 
-- 
2.13.6