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xsk: add missing write- and data-dependency barrier

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Here, we add a missing write-barrier, and use READ_ONCE for the
data-dependency barrier.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Björn Töpel 2018-05-22 09:35:01 +02:00 committed by Daniel Borkmann
parent 1c4917da36
commit 37b076933a
1 changed files with 9 additions and 5 deletions
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14
net/xdp/xsk.c
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@ -228,6 +228,8 @@ static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
if (!q) if (!q)
return -ENOMEM; return -ENOMEM;
/* Make sure queue is ready before it can be seen by others */
smp_wmb();
*queue = q; *queue = q;
return 0; 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; unsigned long size = vma->vm_end - vma->vm_start;
struct xdp_sock *xs = xdp_sk(sock->sk); struct xdp_sock *xs = xdp_sk(sock->sk);
struct xsk_queue *q = NULL; struct xsk_queue *q = NULL;
struct xdp_umem *umem;
unsigned long pfn; unsigned long pfn;
struct page *qpg; struct page *qpg;
if (offset == XDP_PGOFF_RX_RING) { if (offset == XDP_PGOFF_RX_RING) {
q = xs->rx; q = READ_ONCE(xs->rx);
} else if (offset == XDP_PGOFF_TX_RING) { } else if (offset == XDP_PGOFF_TX_RING) {
q = xs->tx; q = READ_ONCE(xs->tx);
} else { } else {
if (!xs->umem) umem = READ_ONCE(xs->umem);
if (!umem)
return -EINVAL; return -EINVAL;
if (offset == XDP_UMEM_PGOFF_FILL_RING) if (offset == XDP_UMEM_PGOFF_FILL_RING)
q = xs->umem->fq; q = READ_ONCE(umem->fq);
else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING) else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
q = xs->umem->cq; q = READ_ONCE(umem->cq);
} }
if (!q) if (!q)