net: thunderx: add mutex to protect mailbox from concurrent calls for…

… same VF

In some cases it could happen that nicvf_send_msg_to_pf() could be called
concurrently for the same NIC VF, and thus re-writing mailbox contents and
breaking messaging sequence with PF by re-writing NICVF data.

This commit is to implement mutex for NICVF to protect mailbox registers
and NICVF messaging control data from concurrent access.

Signed-off-by: Vadim Lomovtsev <vlomovtsev@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cavium/thunder/nic.h

@@ -329,6 +329,8 @@ struct nicvf {
  spinlock_t rx_mode_wq_lock;
  /* workqueue for handling kernel ndo_set_rx_mode() calls */
  struct workqueue_struct *nicvf_rx_mode_wq;
+ /* mutex to protect VF's mailbox contents from concurrent access */
+ struct mutex rx_mode_mtx;
 
  /* PTP timestamp */
  struct cavium_ptp *ptp_clock;

drivers/net/ethernet/cavium/thunder/nicvf_main.c

@@ -124,6 +124,9 @@ int nicvf_send_msg_to_pf(struct nicvf *nic, union nic_mbx *mbx)
 {
  int timeout = NIC_MBOX_MSG_TIMEOUT;
  int sleep = 10;
+ int ret = 0;
+
+ mutex_lock(&nic->rx_mode_mtx);
 
  nic->pf_acked = false;
  nic->pf_nacked = false;
@@ -136,7 +139,8 @@ int nicvf_send_msg_to_pf(struct nicvf *nic, union nic_mbx *mbx)
  netdev_err(nic->netdev,
  "PF NACK to mbox msg 0x%02x from VF%d\n",
  (mbx->msg.msg & 0xFF), nic->vf_id);
- return -EINVAL;
+ ret = -EINVAL;
+ break;
  }
  msleep(sleep);
  if (nic->pf_acked)
@@ -146,10 +150,12 @@ int nicvf_send_msg_to_pf(struct nicvf *nic, union nic_mbx *mbx)
  netdev_err(nic->netdev,
  "PF didn't ACK to mbox msg 0x%02x from VF%d\n",
  (mbx->msg.msg & 0xFF), nic->vf_id);
- return -EBUSY;
+ ret = -EBUSY;
+ break;
  }
  }
- return 0;
+ mutex_unlock(&nic->rx_mode_mtx);
+ return ret;
 }
 
 /* Checks if VF is able to comminicate with PF
@@ -2208,6 +2214,7 @@ static int nicvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
  nic->vf_id);
  INIT_WORK(&nic->rx_mode_work.work, nicvf_set_rx_mode_task);
  spin_lock_init(&nic->rx_mode_wq_lock);
+ mutex_init(&nic->rx_mode_mtx);
 
  err = register_netdev(netdev);
  if (err) {