From 37b076933a8e38e72ffd3c40d3eeb5949f38baf3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Tue, 22 May 2018 09:35:01 +0200 Subject: [PATCH] xsk: add missing write- and data-dependency barrier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Here, we add a missing write-barrier, and use READ_ONCE for the data-dependency barrier. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 378dd9287da5..01f010ec0c05 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -228,6 +228,8 @@ static int xsk_init_queue(u32 entries, struct xsk_queue **queue, if (!q) return -ENOMEM; + /* Make sure queue is ready before it can be seen by others */ + smp_wmb(); *queue = q; return 0; } @@ -532,21 +534,23 @@ static int xsk_mmap(struct file *file, struct socket *sock, unsigned long size = vma->vm_end - vma->vm_start; struct xdp_sock *xs = xdp_sk(sock->sk); struct xsk_queue *q = NULL; + struct xdp_umem *umem; unsigned long pfn; struct page *qpg; if (offset == XDP_PGOFF_RX_RING) { - q = xs->rx; + q = READ_ONCE(xs->rx); } else if (offset == XDP_PGOFF_TX_RING) { - q = xs->tx; + q = READ_ONCE(xs->tx); } else { - if (!xs->umem) + umem = READ_ONCE(xs->umem); + if (!umem) return -EINVAL; if (offset == XDP_UMEM_PGOFF_FILL_RING) - q = xs->umem->fq; + q = READ_ONCE(umem->fq); else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING) - q = xs->umem->cq; + q = READ_ONCE(umem->cq); } if (!q)