scsi: qla2xxx: Fix for double free of SRB structure

This patch fixes issue during switch command query where driver was freeing
SRB resources multiple times

Following stack trace will be seen
[  853.436234] BUG: unable to handle kernel NULL pointer dereference at
0000000000000001
[  853.436348] IP: [<ffffffff811df514>] kmem_cache_alloc+0x74/0x1e0
[  853.436476] PGD 0
[  853.436601] Oops: 0000 [#1] SMP

[  853.454700]  [<ffffffff81099f6a>] ? mod_timer+0x14a/0x220
[  853.455543]  [<ffffffff81185465>] mempool_alloc_slab+0x15/0x20
[  853.456395]  [<ffffffff811855a9>] mempool_alloc+0x69/0x170
[  853.457257]  [<ffffffff81098af2>] ? internal_add_timer+0x32/0x70
[  853.458136]  [<ffffffffc0092d2b>] qla2xxx_queuecommand+0x29b/0x3f0 [qla2xxx]
[  853.459024]  [<ffffffff8146535a>] scsi_dispatch_cmd+0xaa/0x230
[  853.459923]  [<ffffffff8146e11f>] scsi_request_fn+0x4df/0x680
[  853.460829]  [<ffffffff81029557>] ? __switch_to+0xd7/0x510
[  853.461747]  [<ffffffff812f7113>] __blk_run_queue+0x33/0x40
[  853.462670]  [<ffffffff812f7735>] blk_delay_work+0x25/0x40
[  853.463603]  [<ffffffff810a882a>] process_one_work+0x17a/0x440
[  853.464546]  [<ffffffff810a94f6>] worker_thread+0x126/0x3c0
[  853.465501]  [<ffffffff810a93d0>] ? manage_workers.isra.24+0x2a0/0x2a0
[  853.466447]  [<ffffffff810b099f>] kthread+0xcf/0xe0
[  853.467379]  [<ffffffff810b08d0>] ? insert_kthread_work+0x40/0x40
[  853.470172] Code: db e2 7e 49 8b 50 08 4d 8b 20 49 8b 40 10 4d 85 e4 0f 84 20
01 00 00 48 85 c0 0f 84 17 01 00 00 49 63 46 20 48 8d 4a 01 4d 8b 06 <49> 8b 1c
04 4c 89 e0 65 49 0f c7 08 0f 94 c0 84 c0 74 ba 49 63
[  853.472072] RIP  [<ffffffff811df514>] kmem_cache_alloc+0x74/0x1e0
[  853.472971]  RSP <ffff88103726fc50>

Fixes: 726b8548 ("qla2xxx: Add framework for async fabric discovery")
Cc: <stable@vger.kernel.org>
Signed-off-by: Giridhar Malavali <giridhar.malavali@cavium.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_gs.c

@@ -3027,6 +3027,9 @@ static void qla24xx_async_gpsc_sp_done(void *s, int res)
 	    "Async done-%s res %x, WWPN %8phC \n",
 	    sp->name, res, fcport->port_name);
 
+	if (res == QLA_FUNCTION_TIMEOUT)
+		return;
+
 	if (res == (DID_ERROR << 16)) {
 		/* entry status error */
 		goto done;

drivers/scsi/qla2xxx/qla_init.c

@@ -52,12 +52,14 @@ qla2x00_sp_timeout(struct timer_list *t)
 	struct srb_iocb *iocb;
 	struct req_que *req;
 	unsigned long flags;
+	struct qla_hw_data *ha = sp->vha->hw;
 
-	spin_lock_irqsave(sp->qpair->qp_lock_ptr, flags);
+	WARN_ON(irqs_disabled());
+	spin_lock_irqsave(&ha->hardware_lock, flags);
 	req = sp->qpair->req;
 	req->outstanding_cmds[sp->handle] = NULL;
 	iocb = &sp->u.iocb_cmd;
-	spin_unlock_irqrestore(sp->qpair->qp_lock_ptr, flags);
+	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 	iocb->timeout(sp);
 }
 
@@ -970,6 +972,15 @@ void qla24xx_async_gpdb_sp_done(void *s, int res)
 
 	fcport->flags &= ~(FCF_ASYNC_SENT | FCF_ASYNC_ACTIVE);
 
+	if (res == QLA_FUNCTION_TIMEOUT)
+		return;
+
+	if (res == QLA_FUNCTION_TIMEOUT) {
+		dma_pool_free(sp->vha->hw->s_dma_pool, sp->u.iocb_cmd.u.mbx.in,
+			sp->u.iocb_cmd.u.mbx.in_dma);
+		return;
+	}
+
 	memset(&ea, 0, sizeof(ea));
 	ea.event = FCME_GPDB_DONE;
 	ea.fcport = fcport;