qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH v4] tap: setting error appropriately when callin


From: Jason Wang
Subject: Re: [Qemu-devel] [PATCH v4] tap: setting error appropriately when calling net_init_tap_one()
Date: Fri, 2 Mar 2018 14:30:29 +0800
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0



On 2018年02月06日 20:53, Jay Zhou wrote:
If netdev_add tap,id=net0,...,vhost=on failed in net_init_tap_one(),
the followed up device_add virtio-net-pci,netdev=net0 will fail
too, prints:

    TUNSETOFFLOAD ioctl() failed: Bad file descriptor TUNSETOFFLOAD
    ioctl() failed: Bad file descriptor

The reason is that the fd of tap is closed when error occured after
calling net_init_tap_one().

The fd should be closed when calling net_init_tap_one failed:
    - if tap_set_sndbuf() failed
    - if tap_set_sndbuf() succeeded but vhost failed to open or
      initialize with vhostforce flag on
The fd should not be closed just because vhost failed to open or
initialize but without vhostforce flag. So the followed up
device_add can fall back to userspace virtio successfully.

Suggested-by: Michael S. Tsirkin <address@hidden>
Suggested-by: Igor Mammedov <address@hidden>
Suggested-by: Jason Wang <address@hidden>
Signed-off-by: Jay Zhou <address@hidden>
---
v4: - reduce duplication
     - close the fd by caller
     - tweak the title

v3: - set errp appropriately
---
  include/net/vhost_net.h |  3 +++
  net/tap.c               | 24 ++++++++++++++++++------
  2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
index afc1499..77e4739 100644
--- a/include/net/vhost_net.h
+++ b/include/net/vhost_net.h
@@ -4,6 +4,9 @@
  #include "net/net.h"
  #include "hw/virtio/vhost-backend.h"
+#define VHOST_NET_INIT_FAILED \
+    "vhost-net requested but could not be initialized"
+
  struct vhost_net;
  typedef struct vhost_net VHostNetState;
diff --git a/net/tap.c b/net/tap.c
index 979e622..14d230f 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -686,14 +686,23 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
          if (vhostfdname) {
              vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
              if (vhostfd == -1) {
-                error_propagate(errp, err);
+                if (tap->has_vhostforce && tap->vhostforce) {
+                    error_propagate(errp, err);
+                } else {
+                    warn_report_err(err);
+                }
                  return;
              }
          } else {
              vhostfd = open("/dev/vhost-net", O_RDWR);
              if (vhostfd < 0) {
-                error_setg_errno(errp, errno,
-                                 "tap: open vhost char device failed");
+                if (tap->has_vhostforce && tap->vhostforce) {
+                    error_setg_errno(errp, errno,
+                                     "tap: open vhost char device failed");
+                } else {
+                    warn_report("tap: open vhost char device failed: %s",
+                                strerror(errno));
+                }
                  return;
              }
              fcntl(vhostfd, F_SETFL, O_NONBLOCK);
@@ -702,12 +711,15 @@ static void net_init_tap_one(const NetdevTapOptions *tap, 
NetClientState *peer,
s->vhost_net = vhost_net_init(&options);
          if (!s->vhost_net) {
-            error_setg(errp,
-                       "vhost-net requested but could not be initialized");
+            if (tap->has_vhostforce && tap->vhostforce) {
+                error_setg(errp, VHOST_NET_INIT_FAILED);
+            } else {
+                warn_report(VHOST_NET_INIT_FAILED);
+            }
              return;
          }
      } else if (vhostfdname) {
-        error_setg(errp, "vhostfd(s)= is not valid without vhost");
+        warn_report("vhostfd(s)= is not valid without vhost");

Do we need to keep the error here consider it was a wrong command line parameter?

Thanks

      }
  }




reply via email to

[Prev in Thread] Current Thread [Next in Thread]