[PATCH AUTOSEL 5.2 175/249] xsk: Properly terminate assignment in xskq_produce_flush_desc

[PATCH AUTOSEL 5.2 175/249] xsk: Properly terminate assignment in xskq_produce_flush_desc

[Sasha Levin]

From: Nathan Chancellor <natechancellor@gmail.com>

[ Upstream commit f7019b7b0ad14bde732b8953161994edfc384953 ]

Clang warns:

In file included from net/xdp/xsk_queue.c:10:
net/xdp/xsk_queue.h:292:2: warning: expression result unused
[-Wunused-value]
        WRITE_ONCE(q->ring->producer, q->prod_tail);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:284:6: note: expanded from macro 'WRITE_ONCE'
        __u.__val;                                      \
        ~~~ ^~~~~
1 warning generated.

The q->prod_tail assignment has a comma at the end, not a semi-colon.
Fix that so clang no longer warns and everything works as expected.

Fixes: c497176cb2e4 ("xsk: add Rx receive functions and poll support")
Link: https://github.com/ClangBuiltLinux/linux/issues/544
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/xdp/xsk_queue.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 88b9ae24658d..cba4a640d5e8 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -288,7 +288,7 @@ static inline void xskq_produce_flush_desc(struct xsk_queue *q)
 	/* Order producer and data */
 	smp_wmb(); /* B, matches C */
 
-	q->prod_tail = q->prod_head,
+	q->prod_tail = q->prod_head;
 	WRITE_ONCE(q->ring->producer, q->prod_tail);
 }
 
-- 
2.20.1

[PATCH AUTOSEL 5.2 189/249] net/mlx5e: Attach/detach XDP program safely

[Sasha Levin]

From: Maxim Mikityanskiy <maximmi@mellanox.com>

[ Upstream commit e18953240de8b46360a67090c87ee1ef8160b35d ]

When an XDP program is set, a full reopen of all channels happens in two
cases:

1. When there was no program set, and a new one is being set.

2. When there was a program set, but it's being unset.

The full reopen is necessary, because the channel parameters may change
if XDP is enabled or disabled. However, it's performed in an unsafe way:
if the new channels fail to open, the old ones are already closed, and
the interface goes down. Use the safe way to switch channels instead.
The same way is already used for other configuration changes.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 31 ++++++++++++-------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index a8e8350b38aa..8db9fdbc03ea 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -4192,8 +4192,6 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
 	/* no need for full reset when exchanging programs */
 	reset = (!priv->channels.params.xdp_prog || !prog);
 
-	if (was_opened && reset)
-		mlx5e_close_locked(netdev);
 	if (was_opened && !reset) {
 		/* num_channels is invariant here, so we can take the
 		 * batched reference right upfront.
@@ -4205,20 +4203,31 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
 		}
 	}
 
-	/* exchange programs, extra prog reference we got from caller
-	 * as long as we don't fail from this point onwards.
-	 */
-	old_prog = xchg(&priv->channels.params.xdp_prog, prog);
+	if (was_opened && reset) {
+		struct mlx5e_channels new_channels = {};
+
+		new_channels.params = priv->channels.params;
+		new_channels.params.xdp_prog = prog;
+		mlx5e_set_rq_type(priv->mdev, &new_channels.params);
+		old_prog = priv->channels.params.xdp_prog;
+
+		err = mlx5e_safe_switch_channels(priv, &new_channels, NULL);
+		if (err)
+			goto unlock;
+	} else {
+		/* exchange programs, extra prog reference we got from caller
+		 * as long as we don't fail from this point onwards.
+		 */
+		old_prog = xchg(&priv->channels.params.xdp_prog, prog);
+	}
+
 	if (old_prog)
 		bpf_prog_put(old_prog);
 
-	if (reset) /* change RQ type according to priv->xdp_prog */
+	if (!was_opened && reset) /* change RQ type according to priv->xdp_prog */
 		mlx5e_set_rq_type(priv->mdev, &priv->channels.params);
 
-	if (was_opened && reset)
-		err = mlx5e_open_locked(netdev);
-
-	if (!test_bit(MLX5E_STATE_OPENED, &priv->state) || reset)
+	if (!was_opened || reset)
 		goto unlock;
 
 	/* exchanging programs w/o reset, we update ref counts on behalf
-- 
2.20.1

[PATCH AUTOSEL 5.2 248/249] xdp: fix race on generic receive path

[Sasha Levin]

From: Ilya Maximets <i.maximets@samsung.com>

[ Upstream commit bf0bdd1343efbbf65b4d53aef1fce14acbd79d50 ]

Unlike driver mode, generic xdp receive could be triggered
by different threads on different CPU cores at the same time
leading to the fill and rx queue breakage. For example, this
could happen while sending packets from two processes to the
first interface of veth pair while the second part of it is
open with AF_XDP socket.

Need to take a lock for each generic receive to avoid race.

Fixes: c497176cb2e4 ("xsk: add Rx receive functions and poll support")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Tested-by: William Tu <u9012063@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/xdp_sock.h |  2 ++
 net/xdp/xsk.c          | 31 ++++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index d074b6d60f8a..ac3c047d058c 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -67,6 +67,8 @@ struct xdp_sock {
 	 * in the SKB destructor callback.
 	 */
 	spinlock_t tx_completion_lock;
+	/* Protects generic receive. */
+	spinlock_t rx_lock;
 	u64 rx_dropped;
 };
 
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index a14e8864e4fa..5e0637db92ea 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -123,13 +123,17 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 	u64 addr;
 	int err;
 
-	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
-		return -EINVAL;
+	spin_lock_bh(&xs->rx_lock);
+
+	if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
 
 	if (!xskq_peek_addr(xs->umem->fq, &addr) ||
 	    len > xs->umem->chunk_size_nohr - XDP_PACKET_HEADROOM) {
-		xs->rx_dropped++;
-		return -ENOSPC;
+		err = -ENOSPC;
+		goto out_drop;
 	}
 
 	addr += xs->umem->headroom;
@@ -138,13 +142,21 @@ int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
 	memcpy(buffer, xdp->data_meta, len + metalen);
 	addr += metalen;
 	err = xskq_produce_batch_desc(xs->rx, addr, len);
-	if (!err) {
-		xskq_discard_addr(xs->umem->fq);
-		xsk_flush(xs);
-		return 0;
-	}
+	if (err)
+		goto out_drop;
+
+	xskq_discard_addr(xs->umem->fq);
+	xskq_produce_flush_desc(xs->rx);
 
+	spin_unlock_bh(&xs->rx_lock);
+
+	xs->sk.sk_data_ready(&xs->sk);
+	return 0;
+
+out_drop:
 	xs->rx_dropped++;
+out_unlock:
+	spin_unlock_bh(&xs->rx_lock);
 	return err;
 }
 
@@ -765,6 +777,7 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol,
 
 	xs = xdp_sk(sk);
 	mutex_init(&xs->mutex);
+	spin_lock_init(&xs->rx_lock);
 	spin_lock_init(&xs->tx_completion_lock);
 
 	mutex_lock(&net->xdp.lock);
-- 
2.20.1