From: Tushar Dave <tushar.n.dave@oracle.com>
Date: Wed, 12 Sep 2018 22:15:29 +0200
Subject: bpf: use __GFP_COMP while allocating page
Patch-mainline: v4.19-rc5
Git-commit: 4c3d795cb012a378855543a775408fba1ccff6f2
References: bsc#1109837

Helper bpg_msg_pull_data() can allocate multiple pages while
linearizing multiple scatterlist elements into one shared page.
However, if the shared page has size > PAGE_SIZE, using
copy_page_to_iter() causes below warning.

e.g.
[ 6367.019832] WARNING: CPU: 2 PID: 7410 at lib/iov_iter.c:825
page_copy_sane.part.8+0x0/0x8

To avoid above warning, use __GFP_COMP while allocating multiple
contiguous pages.

Fixes: 015632bb30da ("bpf: sk_msg program helper bpf_sk_msg_pull_data")
Signed-off-by: Tushar Dave <tushar.n.dave@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 net/core/filter.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2319,7 +2319,8 @@ BPF_CALL_4(bpf_msg_pull_data,
 	if (unlikely(bytes_sg_total > copy))
 		return -EINVAL;
 
-	page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC, get_order(copy));
+	page = alloc_pages(__GFP_NOWARN | GFP_ATOMIC | __GFP_COMP,
+			   get_order(copy));
 	if (unlikely(!page))
 		return -ENOMEM;
 	p = page_address(page);