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_get_target_prop(struct megasas_instance *instance,
			struct scsi_device *sdev)
{
	int ret;
	struct megasas_cmd *cmd;
	struct megasas_dcmd_frame *dcmd;
	u16 targetId = (sdev->channel % 2) + sdev->id;

	cmd = megasas_get_cmd(instance);

	if (!cmd) {
		dev_err(&instance->pdev->dev,
			"Failed to get cmd %s\n", __func__);
		return -ENOMEM;
	}

	dcmd = &cmd->frame->dcmd;

	memset(instance->tgt_prop, 0, sizeof(*instance->tgt_prop));
	memset(dcmd->mbox.b, 0, MFI_MBOX_SIZE);
	dcmd->mbox.b[0] = MEGASAS_IS_LOGICAL(sdev);

	dcmd->mbox.s[1] = cpu_to_le16(targetId);
	dcmd->cmd = MFI_CMD_DCMD;
	dcmd->cmd_status = 0xFF;
	dcmd->sge_count = 1;
	dcmd->flags = MFI_FRAME_DIR_READ;
	dcmd->timeout = 0;
	dcmd->pad_0 = 0;
	dcmd->data_xfer_len =
		cpu_to_le32(sizeof(struct MR_TARGET_PROPERTIES));
	dcmd->opcode = cpu_to_le32(MR_DCMD_DRV_GET_TARGET_PROP);

	megasas_set_dma_settings(instance, dcmd, instance->tgt_prop_h,
				 sizeof(struct MR_TARGET_PROPERTIES));

	if ((instance->adapter_type != MFI_SERIES) &&
	    !instance->mask_interrupts)
		ret = megasas_issue_blocked_cmd(instance,
						cmd, MFI_IO_TIMEOUT_SECS);
	else
		ret = megasas_issue_polled(instance, cmd);

	switch (ret) {
	case DCMD_TIMEOUT:
		switch (dcmd_timeout_ocr_possible(instance)) {
		case INITIATE_OCR:
			cmd->flags |= DRV_DCMD_SKIP_REFIRE;
			megasas_reset_fusion(instance->host,
					     MFI_IO_TIMEOUT_OCR);
			break;
		case KILL_ADAPTER:
			megaraid_sas_kill_hba(instance);
			break;
		case IGNORE_TIMEOUT:
			dev_info(&instance->pdev->dev,
				 "Ignore DCMD timeout: %s %d\n",
				 __func__, __LINE__);
			break;
		}
		break;

	default:
		megasas_return_cmd(instance, cmd);
	}
	if (ret != DCMD_SUCCESS)
		dev_err(&instance->pdev->dev,
			"return from %s %d return value %d\n",
			__func__, __LINE__, ret);

	return ret;
}

megasas_get_target_prop(struct megasas_instance *instance,
			struct scsi_device *sdev)
{
	int ret;
	struct megasas_cmd *cmd;
	struct megasas_dcmd_frame *dcmd;
	u16 targetId = (sdev->channel % 2) + sdev->id;

	cmd = megasas_get_cmd(instance);

	if (!cmd) {
		dev_err(&instance->pdev->dev,
			"Failed to get cmd %s\n", __func__);
		return -ENOMEM;
	}

	dcmd = &cmd->frame->dcmd;

	memset(instance->tgt_prop, 0, sizeof(*instance->tgt_prop));
	memset(dcmd->mbox.b, 0, MFI_MBOX_SIZE);
	dcmd->mbox.b[0] = MEGASAS_IS_LOGICAL(sdev);

	dcmd->mbox.s[1] = cpu_to_le16(targetId);
	dcmd->cmd = MFI_CMD_DCMD;
	dcmd->cmd_status = 0xFF;
	dcmd->sge_count = 1;
	dcmd->flags = MFI_FRAME_DIR_READ;
	dcmd->timeout = 0;
	dcmd->pad_0 = 0;
	dcmd->data_xfer_len =
		cpu_to_le32(sizeof(struct MR_TARGET_PROPERTIES));
	dcmd->opcode = cpu_to_le32(MR_DCMD_DRV_GET_TARGET_PROP);

	megasas_set_dma_settings(instance, dcmd, instance->tgt_prop_h,
				 sizeof(struct MR_TARGET_PROPERTIES));

	if ((instance->adapter_type != MFI_SERIES) &&
	    !instance->mask_interrupts)
		ret = megasas_issue_blocked_cmd(instance,
						cmd, MFI_IO_TIMEOUT_SECS);
	else
		ret = megasas_issue_polled(instance, cmd);

	switch (ret) {
	case DCMD_TIMEOUT:
		switch (dcmd_timeout_ocr_possible(instance)) {
		case INITIATE_OCR:
			cmd->flags |= DRV_DCMD_SKIP_REFIRE;
			megasas_reset_fusion(instance->host,
					     MFI_IO_TIMEOUT_OCR);
			break;
		case KILL_ADAPTER:
			megaraid_sas_kill_hba(instance);
			break;
		case IGNORE_TIMEOUT:
			dev_info(&instance->pdev->dev,
				 "Ignore DCMD timeout: %s %d\n",
				 __func__, __LINE__);
			break;
		}
		break;

	default:
		megasas_return_cmd(instance, cmd);
	}
	if (ret != DCMD_SUCCESS)
		dev_err(&instance->pdev->dev,
			"return from %s %d return value %d\n",
			__func__, __LINE__, ret);

	return ret;
}
