The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2855b33514d290c51d52d94e25d3ef942cd4d578 Mon Sep 17 00:00:00 2001

From: "Michael S. Tsirkin" mst@redhat.com Date: Fri, 20 Apr 2018 19:54:23 +0300 Subject: [PATCH] virtio_console: don't tie bufs to a vq

an allocated buffer doesn't need to be tied to a vq - only vq->vdev is ever used. Pass the function the just what it needs - the vdev.

Cc: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin mst@redhat.com

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 468f06134012..3e56f328b4cb 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -422,7 +422,7 @@ static void reclaim_dma_bufs(void) } }

-static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size, +static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size, int pages) { struct port_buffer *buf; @@ -445,16 +445,16 @@ static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size, return buf; }

- if (is_rproc_serial(vq->vdev)) { + if (is_rproc_serial(vdev)) { /* * Allocate DMA memory from ancestor. When a virtio * device is created by remoteproc, the DMA memory is * associated with the grandparent device: * vdev => rproc => platform-dev. */ - if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent) + if (!vdev->dev.parent || !vdev->dev.parent->parent) goto free_buf; - buf->dev = vq->vdev->dev.parent->parent; + buf->dev = vdev->dev.parent->parent;

/* Increase device refcnt to avoid freeing it */ get_device(buf->dev); @@ -838,7 +838,7 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,

count = min((size_t)(32 * 1024), count);

- buf = alloc_buf(port->out_vq, count, 0); + buf = alloc_buf(port->portdev->vdev, count, 0); if (!buf) return -ENOMEM;

@@ -957,7 +957,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe, if (ret < 0) goto error_out;

- buf = alloc_buf(port->out_vq, 0, pipe->nrbufs); + buf = alloc_buf(port->portdev->vdev, 0, pipe->nrbufs); if (!buf) { ret = -ENOMEM; goto error_out; @@ -1374,7 +1374,7 @@ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)

nr_added_bufs = 0; do { - buf = alloc_buf(vq, PAGE_SIZE, 0); + buf = alloc_buf(vq->vdev, PAGE_SIZE, 0); if (!buf) break;