nfp: add a mutex lock for the vNIC ctrl BAR

Soon we will try to write to the vNIC mailbox without RTNL held.
Add a new mutex to protect access to specific parts of the PCI
control BAR.

Move the mailbox size checking to the mailbox lock() helper, where
it can be more effective (happen prior to potential overwrite of
other data).

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 60 insertions, 12 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 60f2da438990..ab84a6c1ce66 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
@@ -23,6 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/lockdep.h>
 #include <linux/mm.h>
 #include <linux/overflow.h>
 #include <linux/page_ref.h>
@@ -260,7 +261,7 @@ static void nfp_net_reconfig_wait_posted(struct nfp_net *nn)
 }
 
 /**
- * nfp_net_reconfig() - Reconfigure the firmware
+ * __nfp_net_reconfig() - Reconfigure the firmware
  * @nn:      NFP Net device to reconfigure
  * @update:  The value for the update field in the BAR config
  *
@@ -270,10 +271,12 @@ static void nfp_net_reconfig_wait_posted(struct nfp_net *nn)
  *
  * Return: Negative errno on error, 0 on success
  */
-int nfp_net_reconfig(struct nfp_net *nn, u32 update)
+static int __nfp_net_reconfig(struct nfp_net *nn, u32 update)
 {
 	int ret;
 
+	lockdep_assert_held(&nn->bar_lock);
+
 	nfp_net_reconfig_sync_enter(nn);
 
 	nfp_net_reconfig_start(nn, update);
@@ -291,8 +294,31 @@ int nfp_net_reconfig(struct nfp_net *nn, u32 update)
 	return ret;
 }
 
+int nfp_net_reconfig(struct nfp_net *nn, u32 update)
+{
+	int ret;
+
+	nn_ctrl_bar_lock(nn);
+	ret = __nfp_net_reconfig(nn, update);
+	nn_ctrl_bar_unlock(nn);
+
+	return ret;
+}
+
+int nfp_net_mbox_lock(struct nfp_net *nn, unsigned int data_size)
+{
+	if (nn->tlv_caps.mbox_len < NFP_NET_CFG_MBOX_SIMPLE_VAL + data_size) {
+		nn_err(nn, "mailbox too small for %u of data (%u)\n",
+		       data_size, nn->tlv_caps.mbox_len);
+		return -EIO;
+	}
+
+	nn_ctrl_bar_lock(nn);
+	return 0;
+}
+
 /**
- * nfp_net_reconfig_mbox() - Reconfigure the firmware via the mailbox
+ * nfp_net_mbox_reconfig() - Reconfigure the firmware via the mailbox
  * @nn:        NFP Net device to reconfigure
  * @mbox_cmd:  The value for the mailbox command
  *
@@ -300,19 +326,15 @@ int nfp_net_reconfig(struct nfp_net *nn, u32 update)
  *
  * Return: Negative errno on error, 0 on success
  */
-int nfp_net_reconfig_mbox(struct nfp_net *nn, u32 mbox_cmd)
+int nfp_net_mbox_reconfig(struct nfp_net *nn, u32 mbox_cmd)
 {
 	u32 mbox = nn->tlv_caps.mbox_off;
 	int ret;
 
-	if (!nfp_net_has_mbox(&nn->tlv_caps)) {
-		nn_err(nn, "no mailbox present, command: %u\n", mbox_cmd);
-		return -EIO;
-	}
-
+	lockdep_assert_held(&nn->bar_lock);
 	nn_writeq(nn, mbox + NFP_NET_CFG_MBOX_SIMPLE_CMD, mbox_cmd);
 
-	ret = nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_MBOX);
+	ret = __nfp_net_reconfig(nn, NFP_NET_CFG_UPDATE_MBOX);
 	if (ret) {
 		nn_err(nn, "Mailbox update error\n");
 		return ret;
@@ -321,6 +343,15 @@ int nfp_net_reconfig_mbox(struct nfp_net *nn, u32 mbox_cmd)
 	return -nn_readl(nn, mbox + NFP_NET_CFG_MBOX_SIMPLE_RET);
 }
 
+int nfp_net_mbox_reconfig_and_unlock(struct nfp_net *nn, u32 mbox_cmd)
+{
+	int ret;
+
+	ret = nfp_net_mbox_reconfig(nn, mbox_cmd);
+	nn_ctrl_bar_unlock(nn);
+	return ret;
+}
+
 /* Interrupt configuration and handling
  */
 
@@ -3128,7 +3159,9 @@ static int nfp_net_change_mtu(struct net_device *netdev, int new_mtu)
 static int
 nfp_net_vlan_rx_add_vid(struct net_device *netdev, __be16 proto, u16 vid)
 {
+	const u32 cmd = NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_ADD;
 	struct nfp_net *nn = netdev_priv(netdev);
+	int err;
 
 	/* Priority tagged packets with vlan id 0 are processed by the
 	 * NFP as untagged packets
@@ -3136,17 +3169,23 @@ nfp_net_vlan_rx_add_vid(struct net_device *netdev, __be16 proto, u16 vid)
 	if (!vid)
 		return 0;
 
+	err = nfp_net_mbox_lock(nn, NFP_NET_CFG_VLAN_FILTER_SZ);
+	if (err)
+		return err;
+
 	nn_writew(nn, nn->tlv_caps.mbox_off + NFP_NET_CFG_VLAN_FILTER_VID, vid);
 	nn_writew(nn, nn->tlv_caps.mbox_off + NFP_NET_CFG_VLAN_FILTER_PROTO,
 		  ETH_P_8021Q);
 
-	return nfp_net_reconfig_mbox(nn, NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_ADD);
+	return nfp_net_mbox_reconfig_and_unlock(nn, cmd);
 }
 
 static int
 nfp_net_vlan_rx_kill_vid(struct net_device *netdev, __be16 proto, u16 vid)
 {
+	const u32 cmd = NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_KILL;
 	struct nfp_net *nn = netdev_priv(netdev);
+	int err;
 
 	/* Priority tagged packets with vlan id 0 are processed by the
 	 * NFP as untagged packets
@@ -3154,11 +3193,15 @@ nfp_net_vlan_rx_kill_vid(struct net_device *netdev, __be16 proto, u16 vid)
 	if (!vid)
 		return 0;
 
+	err = nfp_net_mbox_lock(nn, NFP_NET_CFG_VLAN_FILTER_SZ);
+	if (err)
+		return err;
+
 	nn_writew(nn, nn->tlv_caps.mbox_off + NFP_NET_CFG_VLAN_FILTER_VID, vid);
 	nn_writew(nn, nn->tlv_caps.mbox_off + NFP_NET_CFG_VLAN_FILTER_PROTO,
 		  ETH_P_8021Q);
 
-	return nfp_net_reconfig_mbox(nn, NFP_NET_CFG_MBOX_CMD_CTAG_FILTER_KILL);
+	return nfp_net_mbox_reconfig_and_unlock(nn, cmd);
 }
 
 static void nfp_net_stat64(struct net_device *netdev,
@@ -3650,6 +3693,8 @@ nfp_net_alloc(struct pci_dev *pdev, void __iomem *ctrl_bar, bool needs_netdev,
 	nn->dp.txd_cnt = NFP_NET_TX_DESCS_DEFAULT;
 	nn->dp.rxd_cnt = NFP_NET_RX_DESCS_DEFAULT;
 
+	mutex_init(&nn->bar_lock);
+
 	spin_lock_init(&nn->reconfig_lock);
 	spin_lock_init(&nn->link_status_lock);
 
@@ -3677,6 +3722,9 @@ err_free_nn:
 void nfp_net_free(struct nfp_net *nn)
 {
 	WARN_ON(timer_pending(&nn->reconfig_timer) || nn->reconfig_posted);
+
+	mutex_destroy(&nn->bar_lock);
+
 	if (nn->dp.netdev)
 		free_netdev(nn->dp.netdev);
 	else