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 <[email protected]> Cc: Chaitanya Kulkarni <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Jan Kara <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Mikhail Skorzhinskii <[email protected]> Cc: Philipp Reisner <[email protected]> Cc: Sagi Grimberg <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: [email protected] --- 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) -- 2.26.2
