scsi: qedf: Fix crash due to unsolicited FIP VLAN response.

We need to initialize qedf->fipvlan_compl in __qedf_probe so that if we
receive an unsolicited FIP VLAN response, the system doesn't crash due
to trying to complete an uninitialized completion.

Also add a check to see if there are any waiters on the completion so we
don't inadvertantly kick start the discovery process due to the
unsolicited frame.

Fixed the crash:

<1>BUG: unable to handle kernel NULL pointer dereference at (null)
<1>IP: [<ffffffff8105ed71>] __wake_up_common+0x31/0x90
<4>PGD 0
<4>Oops: 0000 [#1] SMP
<4>last sysfs file: /sys/devices/system/cpu/online
<4>CPU 7
<4>Modules linked in: autofs4 nfs lockd fscache auth_rpcgss nfs_acl sunrpc target_core_iblock target_core_file target_core_pscsi target_core_mod configfs bnx2fc cnic fcoe 8021q garp stp llc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables ipv6 vfat fat uinput ipmi_devintf microcode power_meter acpi_ipmi ipmi_si ipmi_msghandler iTCO_wdt iTCO_vendor_support dcdbas sg joydev sb_edac edac_core lpc_ich mfd_core shpchp tg3 ptp pps_core ext4 jbd2 mbcache sr_mod cdrom sd_mod crc_t10dif qedi(U) iscsi_boot_sysfs libiscsi scsi_transport_iscsi uio qedf(U) libfcoe libfc scsi_transport_fc scsi_tgt qede(U) qed(U) ahci megaraid_sas wmi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: speedstep_lib]
<4>
<4>Pid: 1485, comm: qedf_11_ll2 Not tainted 2.6.32-642.el6.x86_64 #1 Dell Inc. PowerEdge R730/0599V5
<4>RIP: 0010:[<ffffffff8105ed71>]  [<ffffffff8105ed71>] __wake_up_common+0x31/0x90
<4>RSP: 0018:ffff881068a83d50  EFLAGS: 00010086
<4>RAX: ffffffffffffffe8 RBX: ffff88106bf42de0 RCX: 0000000000000000
<4>RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff88106bf42de0
<4>RBP: ffff881068a83d90 R08: 0000000000000000 R09: 00000000fffffffe
<4>R10: 0000000000000000 R11: 000000000000000b R12: 0000000000000286
<4>R13: ffff88106bf42de8 R14: 0000000000000000 R15: 0000000000000000
<4>FS:  0000000000000000(0000) GS:ffff88089c460000(0000) knlGS:0000000000000000
<4>CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
<4>CR2: 0000000000000000 CR3: 0000000001a8d000 CR4: 00000000001407e0
<4>DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
<4>Process qedf_11_ll2 (pid: 1485, threadinfo ffff881068a80000, task ffff881068a70040)
<4>Stack:
<4> ffff88106ef00090 0000000300000001 ffff881068a83d90 ffff88106bf42de0
<4><d> 0000000000000286 ffff88106bf42dd8 ffff88106bf40a50 0000000000000002
<4><d> ffff881068a83dc0 ffffffff810634c7 ffff881000000003 000000000000000b
<4>Call Trace:
<4> [<ffffffff810634c7>] complete+0x47/0x60
<4> [<ffffffffa01d37e7>] qedf_fip_recv+0x1c7/0x450 [qedf]
<4> [<ffffffffa01cb3cb>] qedf_ll2_recv_thread+0x33b/0x510 [qedf]
<4> [<ffffffffa01cb090>] ? qedf_ll2_recv_thread+0x0/0x510 [qedf]
<4> [<ffffffff810a662e>] kthread+0x9e/0xc0
<4> [<ffffffff8100c28a>] child_rip+0xa/0x20
<4> [<ffffffff810a6590>] ? kthread+0x0/0xc0
<4> [<ffffffff8100c280>] ? child_rip+0x0/0x20
<4>Code: 41 56 41 55 41 54 53 48 83 ec 18 0f 1f 44 00 00 89 75 cc 89 55 c8 4c 8d 6f 08 48 8b 57 08 41 89 cf 4d 89 c6 48 8d 42 e8 49 39 d5 <48> 8b 58 18 74 3f 48 83 eb 18 eb 0a 0f 1f 00 48 89 d8 48 8d 5a
<1>RIP  [<ffffffff8105ed71>] __wake_up_common+0x31/0x90
<4> RSP <ffff881068a83d50>
<4>CR2: 0000000000000000

Signed-off-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedf/qedf_fip.c

@@ -99,7 +99,8 @@ static void qedf_fcoe_process_vlan_resp(struct qedf_ctx *qedf,
 		qedf_set_vlan_id(qedf, vid);
 
 		/* Inform waiter that it's ok to call fcoe_ctlr_link up() */
-		complete(&qedf->fipvlan_compl);
+		if (!completion_done(&qedf->fipvlan_compl))
+			complete(&qedf->fipvlan_compl);
 	}
 }
 

drivers/scsi/qedf/qedf_main.c

@@ -2803,6 +2803,7 @@ static int __qedf_probe(struct pci_dev *pdev, int mode)
 		atomic_set(&qedf->num_offloads, 0);
 		qedf->stop_io_on_error = false;
 		pci_set_drvdata(pdev, qedf);
+		init_completion(&qedf->fipvlan_compl);
 
 		QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_INFO,
 		   "QLogic FastLinQ FCoE Module qedf %s, "