[PATCH net-next 08/10] ibmvnic: Disable irq prior to close

[Nathan Fontenot <nfont@linux.vnet.ibm.com>]

From: Brian King <brking@linux.vnet.ibm.com>

    Add some code to call disable_irq on all the vnic interface's irqs.
    This fixes a crash observed when closing an active interface, as
    seen in the oops below when we try to access a buffer in the interrupt
    handler which we've already freed.

    Unable to handle kernel paging request for data at address 0x00000001
    Faulting instruction address: 0xd000000003886824
    Oops: Kernel access of bad area, sig: 11 [#1]
    SMP NR_CPUS=2048 NUMA pSeries
    Modules linked in: ibmvnic(OEN) rpadlpar_io(X) rpaphp(X) tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag rpcsec_
    Supported: No, Unsupported modules are loaded
    CPU: 8 PID: 0 Comm: swapper/8 Tainted: G           OE   NX 4.4.49-92.11-default #1
    task: c00000007f990110 ti: c0000000fffa0000 task.ti: c00000007f9b8000
    NIP: d000000003886824 LR: d000000003886824 CTR: c0000000007eff60
    REGS: c0000000fffa3a70 TRAP: 0300   Tainted: G           OE   NX  (4.4.49-92.11-default)
    MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 22008042  XER: 20000008
    CFAR: c000000000008468 DAR: 0000000000000001 DSISR: 40000000 SOFTE: 0
    GPR00: d000000003886824 c0000000fffa3cf0 d000000003894118 0000000000000000
    GPR04: 0000000000000000 0000000000000000 c000000001249da0 0000000000000000
    GPR08: 000000000000000e 0000000000000000 c0000000ccb00000 d000000003889180
    GPR12: c0000000007eff60 c000000007af4c00 0000000000000001 c0000000010def30
    GPR16: c00000007f9b8000 c000000000b98c30 c00000007f9b8080 c000000000bab858
    GPR20: 0000000000000005 0000000000000000 c0000000ff5d7e80 c0000000f809f648
    GPR24: c0000000ff5d7ec8 0000000000000000 0000000000000000 c0000000ccb001a0
    GPR28: 000000000000000a c0000000f809f600 c0000000fd4cd900 c0000000f9cd5b00
    NIP [d000000003886824] ibmvnic_interrupt_tx+0x114/0x380 [ibmvnic]
    LR [d000000003886824] ibmvnic_interrupt_tx+0x114/0x380 [ibmvnic]
    Call Trace:
    [c0000000fffa3cf0] [d000000003886824] ibmvnic_interrupt_tx+0x114/0x380 [ibmvnic] (unreliable)
    [c0000000fffa3dd0] [c000000000132940] __handle_irq_event_percpu+0x90/0x2e0
    [c0000000fffa3e90] [c000000000132bcc] handle_irq_event_percpu+0x3c/0x90
    [c0000000fffa3ed0] [c000000000132c88] handle_irq_event+0x68/0xc0
    [c0000000fffa3f00] [c000000000137edc] handle_fasteoi_irq+0xec/0x250
    [c0000000fffa3f30] [c000000000131b04] generic_handle_irq+0x54/0x80
    [c0000000fffa3f60] [c000000000011190] __do_irq+0x80/0x1d0
    [c0000000fffa3f90] [c0000000000248d8] call_do_irq+0x14/0x24
    [c00000007f9bb9e0] [c000000000011380] do_IRQ+0xa0/0x120
    [c00000007f9bba40] [c000000000002594] hardware_interrupt_common+0x114/0x180

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index a8b3c57..ce8b147 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -689,6 +689,23 @@ static int ibmvnic_open(struct net_device *netdev)
 	return -ENOMEM;
 }
 
+static void disable_sub_crqs(struct ibmvnic_adapter *adapter)
+{
+	int i;
+
+	if (adapter->tx_scrq) {
+		for (i = 0; i < adapter->req_tx_queues; i++)
+			if (adapter->tx_scrq[i])
+				disable_irq(adapter->tx_scrq[i]->irq);
+	}
+
+	if (adapter->rx_scrq) {
+		for (i = 0; i < adapter->req_rx_queues; i++)
+			if (adapter->rx_scrq[i])
+				disable_irq(adapter->rx_scrq[i]->irq);
+	}
+}
+
 static int ibmvnic_close(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -696,6 +713,7 @@ static int ibmvnic_close(struct net_device *netdev)
 	int i;
 
 	adapter->closing = true;
+	disable_sub_crqs(adapter);
 
 	for (i = 0; i < adapter->req_rx_queues; i++)
 		napi_disable(&adapter->napi[i]);