[PATCH 2/2] libata: Fix NULL pointer of scsi_host in ata_port

[Mike Qiu <qiudayu@linux.vnet.ibm.com>]

In ata_sas_port_alloc(), it haven't initialized scsi_host field in
ata_port, although scsi_host is in parameters list and unused in this
function.

With commit 1871ee134b73 ("libata: support the ata host which implements a queue depth less than 32")
ata_qc_new() try to use scsi_host, while it
is a NULL pointer for ipr IOA and error message shows below:

Unable to handle kernel paging request for data at address 0x00000114
Faulting instruction address: 0xc0000000005c2580
Oops: Kernel access of bad area, sig: 11 [#1]
...
NIP [c0000000005c2580] .ata_qc_new_init+0x30/0x1f0
LR [c0000000005c9384] .ata_scsi_translate+0x44/0x230
Call Trace:
0xc0000003ad332280 (unreliable)
.ata_scsi_translate+0x44/0x230
.ipr_queuecommand+0x2e0/0x780 [ipr]
.scsi_dispatch_cmd+0xec/0x400
.scsi_request_fn+0x52c/0x670
.__blk_run_queue+0x5c/0x80
.blk_execute_rq_nowait+0xf8/0x1c0
.blk_execute_rq+0x88/0x150
.scsi_execute+0xf0/0x1f0
.scsi_execute_req_flags+0xc4/0x170
.scsi_probe_and_add_lun+0x2d4/0xe00
.__scsi_scan_target+0x1a4/0x790
.scsi_scan_channel.part.3+0x80/0xc0
.scsi_scan_host_selected+0x1a0/0x240
.do_scan_async+0x30/0x210
.async_run_entry_fn+0x78/0x1c0
.process_one_work+0x1c4/0x4a0
.worker_thread+0x184/0x600
.kthread+0x10c/0x130
.ret_from_kernel_thread+0x58/0x7c

While scsi_host is unused in ata_sas_port_alloc(), better to set it
in ata_sas_port_alloc() instead of in driver.

Signed-off-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
---
 drivers/ata/libata-scsi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 0586f66..a472b6f 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -4070,6 +4070,7 @@ struct ata_port *ata_sas_port_alloc(struct ata_host *host,
 	ap->flags |= port_info->flags;
 	ap->ops = port_info->port_ops;
 	ap->cbl = ATA_CBL_SATA;
+	ap->scsi_host = shost;
 
 	return ap;
 }
-- 
1.8.1.4