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authorMagnus Karlsson <magnus.karlsson@intel.com>2019-02-08 14:13:50 +0100
committerAlexei Starovoitov <ast@kernel.org>2019-02-10 20:07:17 -0800
commite6762c8bcf982821935a2b1cb33cf8335d0eefae (patch)
treefd8e52fbe9a4f960fb15bd9862492628f28ff413 /net/xdp
parentbpf: only adjust gso_size on bytestream protocols (diff)
downloadlinux-dev-e6762c8bcf982821935a2b1cb33cf8335d0eefae.tar.xz
linux-dev-e6762c8bcf982821935a2b1cb33cf8335d0eefae.zip
xsk: add missing smp_rmb() in xsk_mmap
All the setup code in AF_XDP is protected by a mutex with the exception of the mmap code that cannot use it. To make sure that a process banging on the mmap call at the same time as another process is setting up the socket, smp_wmb() calls were added in the umem registration code and the queue creation code, so that the published structures that xsk_mmap needs would be consistent. However, the corresponding smp_rmb() calls were not added to the xsk_mmap code. This patch adds these calls. Fixes: 37b076933a8e3 ("xsk: add missing write- and data-dependency barrier") Fixes: c0c77d8fb787c ("xsk: add user memory registration support sockopt") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/xdp')
-rw-r--r--net/xdp/xsk.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index a03268454a27..45f3b528dc09 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -669,6 +669,8 @@ static int xsk_mmap(struct file *file, struct socket *sock,
if (!umem)
return -EINVAL;
+ /* Matches the smp_wmb() in XDP_UMEM_REG */
+ smp_rmb();
if (offset == XDP_UMEM_PGOFF_FILL_RING)
q = READ_ONCE(umem->fq);
else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
@@ -678,6 +680,8 @@ static int xsk_mmap(struct file *file, struct socket *sock,
if (!q)
return -EINVAL;
+ /* Matches the smp_wmb() in xsk_init_queue */
+ smp_rmb();
qpg = virt_to_head_page(q->ring);
if (size > (PAGE_SIZE << compound_order(qpg)))
return -EINVAL;