Currently nvme_tcp_try_send_data() doesn't use kernel_sendpage() to send slab pages. But for pages allocated by __get_free_pages() without __GFP_COMP, which also have refcount as 0, they are still sent by kernel_sendpage() to remote end, this is problematic.

The new introduced helper sendpage_ok() checks both PageSlab tag and page_count counter, and returns true if the checking page is OK to be sent by kernel_sendpage().

This patch fixes the page checking issue of nvme_tcp_try_send_data() with sendpage_ok(). If sendpage_ok() returns true, send this page by kernel_sendpage(), otherwise use sock_no_sendpage to handle this page.

Signed-off-by: Coly Li colyli@suse.de Cc: Chaitanya Kulkarni chaitanya.kulkarni@wdc.com Cc: Christoph Hellwig hch@lst.de Cc: Hannes Reinecke hare@suse.de Cc: Jan Kara jack@suse.com Cc: Jens Axboe axboe@kernel.dk Cc: Mikhail Skorzhinskii mskorzhinskiy@solarflare.com Cc: Philipp Reisner philipp.reisner@linbit.com Cc: Sagi Grimberg sagi@grimberg.me Cc: Vlastimil Babka vbabka@suse.com Cc: stable@vger.kernel.org --- drivers/nvme/host/tcp.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 62fbaecdc960..902fe742762b 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -912,12 +912,11 @@ static int nvme_tcp_try_send_data(struct nvme_tcp_request *req) else flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;

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