[PATCH AUTOSEL 5.1 110/141] nvme-tcp: don't use sendpage for SLAB pages

Sasha Levin
2019-07-19T04:28:18Z

From: Mikhail Skorzhinskii <mskorzhinskiy@solarflare.com>

[ Upstream commit 37c15219599f7a4baa73f6e3432afc69ba7cc530 ]

According to commit a10674bf2406 ("tcp: detecting the misuse of
.sendpage for Slab objects") and previous discussion, tcp_sendpage
should not be used for pages that is managed by SLAB, as SLAB is not
taking page reference counters into consideration.

Signed-off-by: Mikhail Skorzhinskii <mskorzhinskiy@solarflare.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/tcp.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 08a2501b9357..606b13d35d16 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -860,7 +860,14 @@ static int nvme_tcp_try_send_data(struct nvme_tcp_request *req)
else
flags |= MSG_MORE;

- ret = kernel_sendpage(queue->sock, page, offset, len, flags);
+ /* can't zcopy slab pages */
+ if (unlikely(PageSlab(page))) {
+ ret = sock_no_sendpage(queue->sock, page, offset, len,
+ flags);
+ } else {
+ ret = kernel_sendpage(queue->sock, page, offset, len,
+ flags);
+ }
if (ret <= 0)
return ret;

--
2.20.1