[SCSI] BusLogic: Fix an oops when intializing multimaster adapter

This fixes an oops caused by buslogic driver when initializing a BusLogic
MultiMaster adapter. Initialization code used scope of a variable
incorrectly which created a NULL pointer. Oops message is below:

BUG: unable to handle kernel NULL pointer dereference at 0000000c
IP: [<c150c137>] blogic_init_mm_probeinfo.isra.17+0x20a/0x583
*pde = 00000000
Oops: 002 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.11.1.puz1 #1
Hardware name:    /Canterwood, BIOS 6.00 PG 05/16/2003
task: f7050000 ti: f7054000 task.ti: f7054000
EIP: 0060:[<c150c137>] EFLAGS: 00010246 CPU:1
EIP is at blogic_init_mm_probeinfo.isra.17+0x20a/0x583
EAX: 00000013 EBX: 00000000 ECX: 00000000 EDX: f8001000
ESI: f71cb800 EDI: f7388000 EBP: 00007800 ESP: f7055c84
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: 0000000c CR3: 0154f000 CR4: 000007d0
Stack:
 0000001c 00000000 c11a59f6 f7055c98 00008130 ffffffff ffffffff 00000000
 00000003 00000000 00000000 00000000 00000013 f8001000 00000001 000003d0
 00000000 00000000 00000000 c14e3f84 f78803c8 00000000 f738c000 000000e9
Call Trace:
 [<c11a59f6>] ? pci_get_subsys+0x33/0x38
 [<c150c4fb>] ? blogic_init_probeinfo_list+0x4b/0x19e
 [<c108d593>] ? __alloc_pages_nodemask+0xe3/0x623
 [<c108d593>] ? __alloc_pages_nodemask+0xe3/0x623
 [<c10fb99e>] ? sysfs_link_sibling+0x61/0x8d
 [<c10b0519>] ? kmem_cache_alloc+0x8b/0xb5
 [<c150cce5>] ? blogic_init+0xa1/0x10e8
 [<c10fc0a8>] ? sysfs_add_one+0x10/0x9d
 [<c10fc18a>] ? sysfs_addrm_finish+0x12/0x85
 [<c10fca37>] ? sysfs_do_create_link_sd+0x9d/0x1b4
 [<c117c272>] ? blk_register_queue+0x69/0xb3
 [<c10fcb68>] ? sysfs_create_link+0x1a/0x2c
 [<c1181a07>] ? add_disk+0x1a1/0x3c7
 [<c138737b>] ? klist_next+0x60/0xc3
 [<c122cc3a>] ? scsi_dh_detach+0x68/0x68
 [<c1213e36>] ? bus_for_each_dev+0x51/0x61
 [<c1000356>] ? do_one_initcall+0x22/0x12c
 [<c10f3688>] ? __proc_create+0x8c/0xba
 [<c150cc44>] ? blogic_setup+0x5f6/0x5f6
 [<c14e94aa>] ? repair_env_string+0xf/0x4d
 [<c14e949b>] ? do_early_param+0x71/0x71
 [<c103efaa>] ? parse_args+0x21f/0x33d
 [<c14e9a54>] ? kernel_init_freeable+0xdf/0x17d
 [<c14e949b>] ? do_early_param+0x71/0x71
 [<c1388b64>] ? kernel_init+0x8/0xc0
 [<c1392222>] ? ret_from_kernel_thread+0x6/0x28
 [<c1392227>] ? ret_from_kernel_thread+0x1b/0x28
 [<c1388b5c>] ? rest_init+0x6c/0x6c
Code: 89 44 24 10 0f b6 44 24 3d 89 44 24 0c c7 44 24 08 00 00 00 00 c7 44 24 04 38 62 46 c1 c7 04 24 02 00 00 00 e8 78 13 d2 ff 31 db <89> 6b 0c b0 20 89 ea ee
 c7 44 24 08 04 00 00 00 8d 44 24 4c 89
EIP: [<c150c137>] blogic_init_mm_probeinfo.isra.17+0x20a/0x583 SS:ESP 0068:f7055c84
CR2: 000000000000000c
---[ end trace 17f45f5196d40487 ]---
Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
Cc: <stable@vger.kernel.org> # 3.11.x
Reported-by: Pierre Uszynski <pierre@rahul.net>
Tested-by: Pierre Uszynski <pierre@rahul.net>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/BusLogic.c

@@ -696,7 +696,7 @@ static int __init blogic_init_mm_probeinfo(struct blogic_adapter *adapter)
 	while ((pci_device = pci_get_device(PCI_VENDOR_ID_BUSLOGIC,
 					PCI_DEVICE_ID_BUSLOGIC_MULTIMASTER,
 					pci_device)) != NULL) {
-		struct blogic_adapter *adapter = adapter;
+		struct blogic_adapter *host_adapter = adapter;
 		struct blogic_adapter_info adapter_info;
 		enum blogic_isa_ioport mod_ioaddr_req;
 		unsigned char bus;
@@ -744,9 +744,9 @@ static int __init blogic_init_mm_probeinfo(struct blogic_adapter *adapter)
 		   known and enabled, note that the particular Standard ISA I/O
 		   Address should not be probed.
 		 */
-		adapter->io_addr = io_addr;
-		blogic_intreset(adapter);
-		if (blogic_cmd(adapter, BLOGIC_INQ_PCI_INFO, NULL, 0,
+		host_adapter->io_addr = io_addr;
+		blogic_intreset(host_adapter);
+		if (blogic_cmd(host_adapter, BLOGIC_INQ_PCI_INFO, NULL, 0,
 				&adapter_info, sizeof(adapter_info)) ==
 				sizeof(adapter_info)) {
 			if (adapter_info.isa_port < 6)
@@ -762,7 +762,7 @@ static int __init blogic_init_mm_probeinfo(struct blogic_adapter *adapter)
 		   I/O Address assigned at system initialization.
 		 */
 		mod_ioaddr_req = BLOGIC_IO_DISABLE;
-		blogic_cmd(adapter, BLOGIC_MOD_IOADDR, &mod_ioaddr_req,
+		blogic_cmd(host_adapter, BLOGIC_MOD_IOADDR, &mod_ioaddr_req,
 				sizeof(mod_ioaddr_req), NULL, 0);
 		/*
 		   For the first MultiMaster Host Adapter enumerated,
@@ -779,12 +779,12 @@ static int __init blogic_init_mm_probeinfo(struct blogic_adapter *adapter)
 
 			fetch_localram.offset = BLOGIC_AUTOSCSI_BASE + 45;
 			fetch_localram.count = sizeof(autoscsi_byte45);
-			blogic_cmd(adapter, BLOGIC_FETCH_LOCALRAM,
+			blogic_cmd(host_adapter, BLOGIC_FETCH_LOCALRAM,
 					&fetch_localram, sizeof(fetch_localram),
 					&autoscsi_byte45,
 					sizeof(autoscsi_byte45));
-			blogic_cmd(adapter, BLOGIC_GET_BOARD_ID, NULL, 0, &id,
-					sizeof(id));
+			blogic_cmd(host_adapter, BLOGIC_GET_BOARD_ID, NULL, 0,
+					&id, sizeof(id));
 			if (id.fw_ver_digit1 == '5')
 				force_scan_order =
 					autoscsi_byte45.force_scan_order;