Commit 117fdae9 authored Jul 26, 2018 by Dariusz Stojaczyk Committed by Jim Harris Aug 01, 2018

virtio: fix false-positive assertion failure on virtqueue_req_add_iovs



We need to decrement the free_cnt before checking
if it reached 0.

Note: the vq_free_cnt overflow is asserted at the
beginning of the function.

Change-Id: I655217785e4425d1cd3c704d24321b643be55dcf
Signed-off-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/420584


Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Chandler-Test-Pool: SPDK Automated Test System <sys_sgsw@intel.com>

parent ea55b039

lib/virtio/virtio.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -548,11 +548,11 @@ virtqueue_req_add_iovs(struct virtqueue vq, struct iovec iovs, uint16_t iovcnt

		vq->req_end = prev_head;
		vq->vq_desc_head_idx = new_head;
		vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - iovcnt);
		if (vq->vq_desc_head_idx == VQ_RING_DESC_CHAIN_END) {
		assert(vq->vq_free_cnt == 0);
		vq->vq_desc_tail_idx = VQ_RING_DESC_CHAIN_END;
		}
		vq->vq_free_cnt = (uint16_t)(vq->vq_free_cnt - iovcnt);
		}

		#define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct vring_desc))