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| author | Magnus Karlsson <magnus.karlsson@intel.com> | 2019-02-08 14:13:50 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-02-10 20:07:17 -0800 |
| commit | e6762c8bcf982821935a2b1cb33cf8335d0eefae (patch) | |
| tree | fd8e52fbe9a4f960fb15bd9862492628f28ff413 /net/xdp/xsk.c | |
| parent | b90efd2258749e04e1b3f71ef0d716f2ac2337e0 (diff) | |
| download | linux-e6762c8bcf982821935a2b1cb33cf8335d0eefae.tar.gz linux-e6762c8bcf982821935a2b1cb33cf8335d0eefae.tar.bz2 linux-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/xsk.c')
| -rw-r--r-- | net/xdp/xsk.c | 4 |
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; |