Commit 8b94174a authored Jan 03, 2018 by Dariusz Stojaczyk Committed by Jim Harris Jan 03, 2018

virtio: fix full-virtqueue handling



Distinguish between "not enough descriptors available"
and "iovcnt > queue depth".

This patch brings back I/O re-queueing for virtio bdev
module. It was temporarily disabled by 451de7e1 [1].

[1] 451de7e1: "virtio: switch to the new virtqueue API"

Change-Id: I4c4f6a6d9d91373ee647ea7cafd53ad999aa6aa2
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/393447


Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

parent 48245f4b

include/spdk_internal/virtio.h

+4 −3

Original line number	Diff line number	Diff line
		@@ -209,9 +209,10 @@ uint16_t virtio_recv_pkts(struct virtqueue vq, void io, uint32_t len, uint16
		* is sent, processed and a response is received, the same object will be
		* returned to the user calling the virtio poll API.
		* \param iovcnt number of required iovectors for the request. This can be
		* higher than than the actual number of descriptors to be added.
		* \return 0 on success or negative errno otherwise. If not enough iovectors
		* are available, -ENOSPC is returned.
		* higher than than the actual number of iovectors to be added.
		* \return 0 on success or negative errno otherwise. If the `iovcnt` is
		* greater than virtqueue depth, -EINVAL is returned. If simply not enough
		* iovectors are available, -ENOMEM is returned.
		*/
		int virtqueue_req_start(struct virtqueue vq, void cookie, int iovcnt);

lib/virtio/virtio.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -448,7 +448,7 @@ virtqueue_req_start(struct virtqueue vq, void cookie, int iovcnt)
		assert(virtio_dev_get_status(vq->vdev) & VIRTIO_CONFIG_S_DRIVER_OK);

		if (iovcnt > vq->vq_free_cnt) {
		return -ENOSPC;
		return iovcnt > vq->vq_nentries ? -EINVAL : -ENOMEM;
		}

		if (vq->req_start != VQ_RING_DESC_CHAIN_END) {