From: Andrea Parri <parri.andrea@gmail.com>
To: Michael Kelley <mikelley@microsoft.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
Andres Beltran <lkmlabelt@gmail.com>,
Saruhan Karademir <skarade@microsoft.com>,
Juan Vazquez <juvazq@microsoft.com>
Subject: Re: [PATCH v7 1/3] Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening
Date: Tue, 8 Sep 2020 09:54:05 +0200 [thread overview]
Message-ID: <20200908075216.GA5638@andrea> (raw)
In-Reply-To: <MW2PR2101MB1052338B4D3B7020A2191EB7D7280@MW2PR2101MB1052.namprd21.prod.outlook.com>
> > @@ -300,6 +303,22 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
> > kv_list[i].iov_len);
> > }
> >
> > + /*
> > + * Allocate the request ID after the data has been copied into the
> > + * ring buffer. Once this request ID is allocated, the completion
> > + * path could find the data and free it.
> > + */
> > +
> > + if (desc->flags == VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED) {
> > + rqst_id = vmbus_next_request_id(&channel->requestor, requestid);
> > + if (rqst_id == VMBUS_RQST_ERROR) {
> > + pr_err("No request id available\n");
> > + return -EAGAIN;
> > + }
> > + }
> > + desc = hv_get_ring_buffer(outring_info) + old_write;
> > + desc->trans_id = (rqst_id == VMBUS_NO_RQSTOR) ? requestid : rqst_id;
> > +
>
> This is a nit, but the above would be clearer to me if written like this:
>
> flags = desc->flags;
> if (flags == VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED) {
> rqst_id = vmbus_next_request_id(&channel->requestor, requestid);
> if (rqst_id == VMBUS_RQST_ERROR) {
> pr_err("No request id available\n");
> return -EAGAIN;
> }
> } else {
> rqst_id = requestid;
> }
> desc = hv_get_ring_buffer(outring_info) + old_write;
> desc->trans_id = rqst_id;
>
> The value of the flags field controls what will be used as the value for the
> rqst_id. Having another test to see which value will be used as the trans_id
> somehow feels a bit redundant. And then rqst_id doesn't have to be initialized.
Agreed, will apply in the next version.
>
> > /* Set previous packet start */
> > prev_indices = hv_get_ring_bufferindices(outring_info);
> >
> > @@ -319,8 +338,13 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
> >
> > hv_signal_on_write(old_write, channel);
> >
> > - if (channel->rescind)
> > + if (channel->rescind) {
> > + if (rqst_id != VMBUS_NO_RQSTOR) {
>
> Of course, with my proposed change, the above test would also have to be for
> the value of the flags field, which actually makes the code a bit more consistent.
Yes, indeed. Thank you for the review and the suggestion.
Andrea
next prev parent reply other threads:[~2020-09-08 7:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 16:19 [PATCH v7 0/3] Drivers: hv: vmbus: vmbus_requestor data structure for VMBus hardening Andrea Parri (Microsoft)
2020-09-07 16:19 ` [PATCH v7 1/3] Drivers: hv: vmbus: Add " Andrea Parri (Microsoft)
2020-09-07 22:01 ` Michael Kelley
2020-09-08 7:54 ` Andrea Parri [this message]
2020-09-14 17:29 ` Michael Kelley
2020-09-15 7:53 ` Andrea Parri
2020-09-15 19:22 ` Michael Kelley
2020-09-07 16:19 ` [PATCH v7 2/3] scsi: storvsc: Use vmbus_requestor to generate transaction IDs " Andrea Parri (Microsoft)
2020-09-07 22:02 ` Michael Kelley
2020-09-07 16:19 ` [PATCH v7 3/3] hv_netvsc: " Andrea Parri (Microsoft)
2020-09-07 22:02 ` Michael Kelley
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