Re: [Qemu-devel] [PATCH v2 4/9] virtio-blk: handle virtio_blk_handle_request() errors

From: Stefan Hajnoczi <stefanha@redhat.com>
To: Greg Kurz <groug@kaod.org>
Cc: qemu-devel@nongnu.org, Kevin Wolf <kwolf@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>, Max Reitz <mreitz@redhat.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Cornelia Huck <cornelia.huck@de.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 4/9] virtio-blk: handle virtio_blk_handle_request() errors
Date: Fri, 23 Sep 2016 13:58:56 +0100	[thread overview]
Message-ID: <20160923125856.GJ8221@stefanha-x1.localdomain> (raw)
In-Reply-To: <147447704092.30952.7983028961569052217.stgit@bahia>

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On Wed, Sep 21, 2016 at 06:57:20PM +0200, Greg Kurz wrote:
> @@ -586,13 +589,16 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
>      blk_io_plug(s->blk);
>  
>      while ((req = virtio_blk_get_request(s, vq))) {
> -        virtio_blk_handle_request(req, &mrb);
> +        if (virtio_blk_handle_request(req, &mrb)) {
> +            goto out_err;
> +        }
>      }
>  
>      if (mrb.num_reqs) {
>          virtio_blk_submit_multireq(s->blk, &mrb);
>      }
>  
> +out_err:
>      blk_io_unplug(s->blk);

req is leaked.  We must detach it from the virtqueue and free it.

>  }
>  
> @@ -625,7 +631,9 @@ static void virtio_blk_dma_restart_bh(void *opaque)
>  
>      while (req) {
>          VirtIOBlockReq *next = req->next;
> -        virtio_blk_handle_request(req, &mrb);
> +        if (virtio_blk_handle_request(req, &mrb)) {
> +            return;

s->rq is leaked.  We must detach and free the remaining requests.  See
virtio_blk_reset().

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