scsi: megaraid_sas: return error when create DMA pool failed

when create DMA pool for cmd frames failed, we should return -ENOMEM,
instead of 0.
In some case in:

    megasas_init_adapter_fusion()

    -->megasas_alloc_cmds()
       -->megasas_create_frame_pool
          create DMA pool failed,
        --> megasas_free_cmds() [1]

    -->megasas_alloc_cmds_fusion()
       failed, then goto fail_alloc_cmds.
    -->megasas_free_cmds() [2]

we will call megasas_free_cmds twice, [1] will kfree cmd_list,
[2] will use cmd_list.it will cause a problem:

Unable to handle kernel NULL pointer dereference at virtual address
00000000
pgd = ffffffc000f70000
[00000000] *pgd=0000001fbf893003, *pud=0000001fbf893003,
*pmd=0000001fbf894003, *pte=006000006d000707
Internal error: Oops: 96000005 [#1] SMP
 Modules linked in:
 CPU: 18 PID: 1 Comm: swapper/0 Not tainted
 task: ffffffdfb9290000 ti: ffffffdfb923c000 task.ti: ffffffdfb923c000
 PC is at megasas_free_cmds+0x30/0x70
 LR is at megasas_free_cmds+0x24/0x70
 ...
 Call trace:
 [<ffffffc0005b779c>] megasas_free_cmds+0x30/0x70
 [<ffffffc0005bca74>] megasas_init_adapter_fusion+0x2f4/0x4d8
 [<ffffffc0005b926c>] megasas_init_fw+0x2dc/0x760
 [<ffffffc0005b9ab0>] megasas_probe_one+0x3c0/0xcd8
 [<ffffffc0004a5abc>] local_pci_probe+0x4c/0xb4
 [<ffffffc0004a5c40>] pci_device_probe+0x11c/0x14c
 [<ffffffc00053a5e4>] driver_probe_device+0x1ec/0x430
 [<ffffffc00053a92c>] __driver_attach+0xa8/0xb0
 [<ffffffc000538178>] bus_for_each_dev+0x74/0xc8
  [<ffffffc000539e88>] driver_attach+0x28/0x34
 [<ffffffc000539a18>] bus_add_driver+0x16c/0x248
 [<ffffffc00053b234>] driver_register+0x6c/0x138
 [<ffffffc0004a5350>] __pci_register_driver+0x5c/0x6c
 [<ffffffc000ce3868>] megasas_init+0xc0/0x1a8
 [<ffffffc000082a58>] do_one_initcall+0xe8/0x1ec
 [<ffffffc000ca7be8>] kernel_init_freeable+0x1c8/0x284
 [<ffffffc0008d90b8>] kernel_init+0x1c/0xe4

Signed-off-by: Jason Yan <yanaijie@huawei.com>
Acked-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
megasas_init_adapter_mfi(struct megasas_instance *instance)
{
	u32 context_sz;
	u32 reply_q_sz;

	/*
	 * Get various operational parameters from status register
	 */
	instance->max_fw_cmds = instance->instancet->read_fw_status_reg(instance) & 0x00FFFF;
	/*
	 * Reduce the max supported cmds by 1. This is to ensure that the
	 * reply_q_sz (1 more than the max cmd that driver may send)
	 * does not exceed max cmds that the FW can support
	 */
	instance->max_fw_cmds = instance->max_fw_cmds-1;
	instance->max_mfi_cmds = instance->max_fw_cmds;
	instance->max_num_sge = (instance->instancet->read_fw_status_reg(instance) & 0xFF0000) >>
					0x10;
	/*
	 * For MFI skinny adapters, MEGASAS_SKINNY_INT_CMDS commands
	 * are reserved for IOCTL + driver's internal DCMDs.
	 */
	if ((instance->pdev->device == PCI_DEVICE_ID_LSI_SAS0073SKINNY) ||
		(instance->pdev->device == PCI_DEVICE_ID_LSI_SAS0071SKINNY)) {
		instance->max_scsi_cmds = (instance->max_fw_cmds -
			MEGASAS_SKINNY_INT_CMDS);
		sema_init(&instance->ioctl_sem, MEGASAS_SKINNY_INT_CMDS);
	} else {
		instance->max_scsi_cmds = (instance->max_fw_cmds -
			MEGASAS_INT_CMDS);
		sema_init(&instance->ioctl_sem, (MEGASAS_MFI_IOCTL_CMDS));
	}

	instance->cur_can_queue = instance->max_scsi_cmds;
	/*
	 * Create a pool of commands
	 */
	if (megasas_alloc_cmds(instance))
		goto fail_alloc_cmds;

	/*
	 * Allocate memory for reply queue. Length of reply queue should
	 * be _one_ more than the maximum commands handled by the firmware.
	 *
	 * Note: When FW completes commands, it places corresponding contex
	 * values in this circular reply queue. This circular queue is a fairly
	 * typical producer-consumer queue. FW is the producer (of completed
	 * commands) and the driver is the consumer.
	 */
	context_sz = sizeof(u32);
	reply_q_sz = context_sz * (instance->max_fw_cmds + 1);

	instance->reply_queue = dma_alloc_coherent(&instance->pdev->dev,
			reply_q_sz, &instance->reply_queue_h, GFP_KERNEL);

	if (!instance->reply_queue) {
		dev_printk(KERN_DEBUG, &instance->pdev->dev, "Out of DMA mem for reply queue\n");
		goto fail_reply_queue;
	}

	if (megasas_issue_init_mfi(instance))
		goto fail_fw_init;

	if (megasas_get_ctrl_info(instance)) {
		dev_err(&instance->pdev->dev, "(%d): Could get controller info "
			"Fail from %s %d\n", instance->unique_id,
			__func__, __LINE__);
		goto fail_fw_init;
	}

	instance->fw_support_ieee = 0;
	instance->fw_support_ieee =
		(instance->instancet->read_fw_status_reg(instance) &
		0x04000000);

	dev_notice(&instance->pdev->dev, "megasas_init_mfi: fw_support_ieee=%d",
			instance->fw_support_ieee);

	if (instance->fw_support_ieee)
		instance->flag_ieee = 1;

	return 0;

fail_fw_init:

	dma_free_coherent(&instance->pdev->dev, reply_q_sz,
			    instance->reply_queue, instance->reply_queue_h);
fail_reply_queue:
	megasas_free_cmds(instance);

fail_alloc_cmds:
	return 1;
}

megasas_init_adapter_mfi(struct megasas_instance *instance)
{
	u32 context_sz;
	u32 reply_q_sz;

	/*
	 * Get various operational parameters from status register
	 */
	instance->max_fw_cmds = instance->instancet->read_fw_status_reg(instance) & 0x00FFFF;
	/*
	 * Reduce the max supported cmds by 1. This is to ensure that the
	 * reply_q_sz (1 more than the max cmd that driver may send)
	 * does not exceed max cmds that the FW can support
	 */
	instance->max_fw_cmds = instance->max_fw_cmds-1;
	instance->max_mfi_cmds = instance->max_fw_cmds;
	instance->max_num_sge = (instance->instancet->read_fw_status_reg(instance) & 0xFF0000) >>
					0x10;
	/*
	 * For MFI skinny adapters, MEGASAS_SKINNY_INT_CMDS commands
	 * are reserved for IOCTL + driver's internal DCMDs.
	 */
	if ((instance->pdev->device == PCI_DEVICE_ID_LSI_SAS0073SKINNY) ||
		(instance->pdev->device == PCI_DEVICE_ID_LSI_SAS0071SKINNY)) {
		instance->max_scsi_cmds = (instance->max_fw_cmds -
			MEGASAS_SKINNY_INT_CMDS);
		sema_init(&instance->ioctl_sem, MEGASAS_SKINNY_INT_CMDS);
	} else {
		instance->max_scsi_cmds = (instance->max_fw_cmds -
			MEGASAS_INT_CMDS);
		sema_init(&instance->ioctl_sem, (MEGASAS_MFI_IOCTL_CMDS));
	}

	instance->cur_can_queue = instance->max_scsi_cmds;
	/*
	 * Create a pool of commands
	 */
	if (megasas_alloc_cmds(instance))
		goto fail_alloc_cmds;

	/*
	 * Allocate memory for reply queue. Length of reply queue should
	 * be _one_ more than the maximum commands handled by the firmware.
	 *
	 * Note: When FW completes commands, it places corresponding contex
	 * values in this circular reply queue. This circular queue is a fairly
	 * typical producer-consumer queue. FW is the producer (of completed
	 * commands) and the driver is the consumer.
	 */
	context_sz = sizeof(u32);
	reply_q_sz = context_sz * (instance->max_fw_cmds + 1);

	instance->reply_queue = dma_alloc_coherent(&instance->pdev->dev,
			reply_q_sz, &instance->reply_queue_h, GFP_KERNEL);

	if (!instance->reply_queue) {
		dev_printk(KERN_DEBUG, &instance->pdev->dev, "Out of DMA mem for reply queue\n");
		goto fail_reply_queue;
	}

	if (megasas_issue_init_mfi(instance))
		goto fail_fw_init;

	if (megasas_get_ctrl_info(instance)) {
		dev_err(&instance->pdev->dev, "(%d): Could get controller info "
			"Fail from %s %d\n", instance->unique_id,
			__func__, __LINE__);
		goto fail_fw_init;
	}

	instance->fw_support_ieee = 0;
	instance->fw_support_ieee =
		(instance->instancet->read_fw_status_reg(instance) &
		0x04000000);

	dev_notice(&instance->pdev->dev, "megasas_init_mfi: fw_support_ieee=%d",
			instance->fw_support_ieee);

	if (instance->fw_support_ieee)
		instance->flag_ieee = 1;

	return 0;

fail_fw_init:

	dma_free_coherent(&instance->pdev->dev, reply_q_sz,
			    instance->reply_queue, instance->reply_queue_h);
fail_reply_queue:
	megasas_free_cmds(instance);

fail_alloc_cmds:
	return 1;
}
