[Intel-wired-lan] [PATCH bpf-next 4/4] i40e: disallow changing the number of descriptors when AF_XDP is on
Björn Töpel
bjorn.topel at gmail.com
Tue Sep 4 18:11:05 UTC 2018
From: Björn Töpel <bjorn.topel at intel.com>
When an AF_XDP UMEM is attached to any of the Rx rings, we disallow a
user to change the number of descriptors via e.g. "ethtool -G IFNAME".
Otherwise, the size of the stash/reuse queue can grow unbounded, which
would result in OOM or leaking userspace buffers.
Signed-off-by: Björn Töpel <bjorn.topel at intel.com>
---
.../net/ethernet/intel/i40e/i40e_ethtool.c | 9 +++++++-
.../ethernet/intel/i40e/i40e_txrx_common.h | 1 +
drivers/net/ethernet/intel/i40e/i40e_xsk.c | 22 +++++++++++++++++++
3 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index d7d3974beca2..3cd2c88c72f8 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -5,7 +5,7 @@
#include "i40e.h"
#include "i40e_diag.h"
-
+#include "i40e_txrx_common.h"
#include "i40e_ethtool_stats.h"
#define I40E_PF_STAT(_name, _stat) \
@@ -1493,6 +1493,13 @@ static int i40e_set_ringparam(struct net_device *netdev,
(new_rx_count == vsi->rx_rings[0]->count))
return 0;
+ /* If there is a AF_XDP UMEM attached to any of Rx rings,
+ * disallow changing the number of descriptors -- regardless
+ * if the netdev is running or not.
+ */
+ if (i40e_xsk_any_rx_ring_enabled(vsi))
+ return -EBUSY;
+
while (test_and_set_bit(__I40E_CONFIG_BUSY, pf->state)) {
timeout--;
if (!timeout)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
index 8d46acff6f2e..09809dffe399 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx_common.h
@@ -89,5 +89,6 @@ static inline void i40e_arm_wb(struct i40e_ring *tx_ring,
void i40e_xsk_clean_rx_ring(struct i40e_ring *rx_ring);
void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring);
+bool i40e_xsk_any_rx_ring_enabled(struct i40e_vsi *vsi);
#endif /* I40E_TXRX_COMMON_ */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
index e4b62e871afc..119f59ec7cc0 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -944,3 +944,25 @@ void i40e_xsk_clean_tx_ring(struct i40e_ring *tx_ring)
if (xsk_frames)
xsk_umem_complete_tx(umem, xsk_frames);
}
+
+/**
+ * i40e_xsk_any_rx_ring_enabled - Checks whether any of the Rx rings
+ * has AF_XDP UMEM attached
+ * @vsi: vsi
+ *
+ * Returns true if any of the Rx rings has an AF_XDP UMEM attached
+ **/
+bool i40e_xsk_any_rx_ring_enabled(struct i40e_vsi *vsi)
+{
+ int i;
+
+ if (!vsi->xsk_umems)
+ return false;
+
+ for (i = 0; i < vsi->num_queue_pairs; i++) {
+ if (vsi->xsk_umems[i])
+ return true;
+ }
+
+ return false;
+}
--
2.17.1
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