scsi: qla2xxx: Fix slow mem alloc behind lock

Call Trace:
 [<ffffffff81341687>] dump_stack+0x6b/0xa4
 [<ffffffff810c3e30>] ? print_irqtrace_events+0xd0/0xe0
 [<ffffffff8109e3c3>] ___might_sleep+0x183/0x240
 [<ffffffff8109e4d2>] __might_sleep+0x52/0x90
 [<ffffffff811fe17b>] kmem_cache_alloc_trace+0x5b/0x300
 [<ffffffff810c666b>] ? __lock_acquired+0x30b/0x420
 [<ffffffffa0733c28>] qla2x00_alloc_fcport+0x38/0x2a0 [qla2xxx]
 [<ffffffffa07217f4>] ? qla2x00_do_work+0x34/0x2b0 [qla2xxx]
 [<ffffffff816cc82b>] ? _raw_spin_lock_irqsave+0x7b/0x90
 [<ffffffffa072169a>] ? qla24xx_create_new_sess+0x3a/0x160 [qla2xxx]
 [<ffffffffa0721723>] qla24xx_create_new_sess+0xc3/0x160 [qla2xxx]
 [<ffffffff810c91ed>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffffa07218f8>] qla2x00_do_work+0x138/0x2b0 [qla2xxx]

Signed-off-by: Quinn Tran <quinn.tran@qlogic.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/qla2xxx/qla_gbl.h b/drivers/scsi/qla2xxx/qla_gbl.h
index 0b219b3..f852ca6 100644
--- a/drivers/scsi/qla2xxx/qla_gbl.h
+++ b/drivers/scsi/qla2xxx/qla_gbl.h
@@ -113,6 +113,7 @@
 extern char qla2x00_version_str[];
 
 extern struct kmem_cache *srb_cachep;
+extern struct kmem_cache *qla_tgt_plogi_cachep;
 
 extern int ql2xlogintimeout;
 extern int qlport_down_retry;