From: Keith Busch <keith.busch@intel.com>
Date: Mon, 10 Dec 2018 15:44:42 +0000 (-0700)
Subject: block/bio: Do not zero user pages
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=f55adad601c6a97c8c9628195453e0fb23b4a0ae;p=openwrt%2Fstaging%2Fblogic.git

block/bio: Do not zero user pages

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 <taiken@mvtech.ca>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: stable@vger.kernel.org
Cc: Bart Van Assche <bvanassche@acm.org>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/bio.c b/block/bio.c
index 4f4d9884443b..4d86e90654b2 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1261,7 +1261,8 @@ 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);
 	}