scsi: qla2xxx: Fix for double free of SRB structure

commit bcc71cc3 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/scsi/qla2xxx/qla_gs.c

@@ -3261,6 +3261,9 @@ 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);
 }
 
@@ -972,6 +974,15 @@ 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;