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Tsirkin" , David Hildenbrand , Jason Wang , Xuan Zhuo , linux-um@lists.infradead.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org Subject: [PATCH vhost v9 1/6] virtio_balloon: remove the dependence where names[] is null Date: Wed, 24 Apr 2024 17:15:28 +0800 Message-Id: <20240424091533.86949-2-xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 2.32.0.3.g01195cf9f In-Reply-To: <20240424091533.86949-1-xuanzhuo@linux.alibaba.com> References: <20240424091533.86949-1-xuanzhuo@linux.alibaba.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Git-Hash: bdb00f35db89 Currently, the init_vqs function within the virtio_balloon driver relies on the condition that certain names array entries are null in order to skip the initialization of some virtual queues (vqs). This behavior is unique to this part of the codebase. In an upcoming commit, we plan to eliminate this dependency by removing the function entirely. Therefore, with this change, we are ensuring that the virtio_balloon no longer depends on the aforementioned function. As specification 1.0-1.2, vq indexes should not be contiguous if some vq does not exist. But currently the virtqueue index is contiguous for all existing devices. The Linux kernel does not implement functionality to allow vq indexes to be discontinuous. So the current behavior of the virtio-balloon device is different for the spec. But this commit has no functional changes. Signed-off-by: Xuan Zhuo Acked-by: David Hildenbrand Acked-by: Jason Wang --- drivers/virtio/virtio_balloon.c | 48 ++++++++++++++------------------- 1 file changed, 20 insertions(+), 28 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index c0a63638f95e..ccda6d08493f 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -548,49 +548,41 @@ static int init_vqs(struct virtio_balloon *vb) struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX]; vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX]; const char *names[VIRTIO_BALLOON_VQ_MAX]; - int err; + int err, idx = 0; - /* - * Inflateq and deflateq are used unconditionally. The names[] - * will be NULL if the related feature is not enabled, which will - * cause no allocation for the corresponding virtqueue in find_vqs. - */ - callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack; - names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate"; - callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack; - names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; - callbacks[VIRTIO_BALLOON_VQ_STATS] = NULL; - names[VIRTIO_BALLOON_VQ_STATS] = NULL; - callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; - names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; - names[VIRTIO_BALLOON_VQ_REPORTING] = NULL; + callbacks[idx] = balloon_ack; + names[idx++] = "inflate"; + callbacks[idx] = balloon_ack; + names[idx++] = "deflate"; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { - names[VIRTIO_BALLOON_VQ_STATS] = "stats"; - callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request; + names[idx] = "stats"; + callbacks[idx++] = stats_request; } if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { - names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq"; - callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; + names[idx] = "free_page_vq"; + callbacks[idx++] = NULL; } if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { - names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq"; - callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack; + names[idx] = "reporting_vq"; + callbacks[idx++] = balloon_ack; } - err = virtio_find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, - callbacks, names, NULL); + err = virtio_find_vqs(vb->vdev, idx, vqs, callbacks, names, NULL); if (err) return err; - vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; - vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; + idx = 0; + + vb->inflate_vq = vqs[idx++]; + vb->deflate_vq = vqs[idx++]; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { struct scatterlist sg; unsigned int num_stats; - vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS]; + vb->stats_vq = vqs[idx++]; /* * Prime this virtqueue with one buffer so the hypervisor can @@ -610,10 +602,10 @@ static int init_vqs(struct virtio_balloon *vb) } if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) - vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE]; + vb->free_page_vq = vqs[idx++]; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) - vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING]; + vb->reporting_vq = vqs[idx++]; return 0; }