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SubjectRE: [PATCH 3/4] scsi: storvsc: Refactor the code in storvsc_channel_init()
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> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
> Sent: Friday, December 11, 2015 2:41 AM
> To: KY Srinivasan <kys@microsoft.com>
> Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; ohering@suse.com;
> jbottomley@parallels.com; hch@infradead.org; linux-scsi@vger.kernel.org;
> apw@canonical.com; vkuznets@redhat.com; jasowang@redhat.com;
> martin.petersen@oracle.com
> Subject: Re: [PATCH 3/4] scsi: storvsc: Refactor the code in
> storvsc_channel_init()
>
> On Thu, Dec 10, 2015 at 04:14:19PM -0800, K. Y. Srinivasan wrote:
> > @@ -753,27 +740,62 @@ static int storvsc_channel_init(struct hv_device
> *device, bool is_fc)
> > VM_PKT_DATA_INBAND,
> >
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
> > if (ret != 0)
> > - goto cleanup;
> > + goto done;
> >
> > t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
> > if (t == 0) {
> > ret = -ETIMEDOUT;
> > - goto cleanup;
> > + goto done;
> > }
> >
> > + if (!status_check)
> > + goto done;
>
> See? This goto looks exactly the same as the earlier buggy goto but
> it's actually correct. Meanwhile if you just used an explicit
> "return 0;" then it would be easy to understand.
>
> I rant about this all the time but it's because it's bad deliberately.
> It's normal to have bugs, but this deliberate stuff really I can't
> understand it...
>
> > +
> > if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO
> ||
> > vstor_packet->status != 0) {
> > ret = -EINVAL;
> > - goto cleanup;
> > + goto done;
> > }
> >
> > +done:
> > + return ret;
> > +}
> > +
> > +static int storvsc_channel_init(struct hv_device *device, bool is_fc)
> > +{
> > + struct storvsc_device *stor_device;
> > + struct storvsc_cmd_request *request;
> > + struct vstor_packet *vstor_packet;
> > + int ret, i;
> > + int max_chns;
> > + bool process_sub_channels = false;
> > +
> > + stor_device = get_out_stor_device(device);
> > + if (!stor_device)
> > + return -ENODEV;
> > +
> > + request = &stor_device->init_request;
> > + vstor_packet = &request->vstor_packet;
> > +
> > + /*
> > + * Now, initiate the vsc/vsp initialization protocol on the open
> > + * channel
> > + */
> > + memset(request, 0, sizeof(struct storvsc_cmd_request));
> > + vstor_packet->operation =
> VSTOR_OPERATION_BEGIN_INITIALIZATION;
> > + ret = storvsc_execute_vstor_op(device, request, true);
> > + if (ret)
> > + goto cleanup;
>
> 10 lines earlier there is an explicit "return -ENODEV" so it's not as if
> writing explicit returns will kill you.

Thanks Dan; I will cleanup the code and resend.

Regards,

K. Y





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