We set queues before reset which will cause a crash[1]. This is
because is_xdp_raw_buffer_queue() depends on the old xdp queue pairs
number to do the correct detection. So fix this by

- passing xdp queue pairs and current queue pairs to virtnet_reset()
- change vi->xdp_qp after reset but before refill, to make sure both
  free_unused_bufs() and refill can make correct detection of XDP.
- remove the duplicated queue pairs setting before virtnet_reset()
  since we will do it inside virtnet_reset()

[1]

[   74.328168] general protection fault: 0000 [#1] SMP
[   74.328625] Modules linked in: nfsd xfs libcrc32c virtio_net virtio_pci
[   74.329117] CPU: 0 PID: 2849 Comm: xdp2 Not tainted 4.10.0-rc7+ #499
[   74.329577] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
[   74.330424] task: ffff88007a894000 task.stack: ffffc90004388000
[   74.330844] RIP: 0010:skb_release_head_state+0x28/0x80
[   74.331298] RSP: 0018:ffffc9000438b8d0 EFLAGS: 00010206
[   74.331676] RAX: 0000000000000000 RBX: ffff88007ad96300 RCX: 0000000000000000
[   74.332217] RDX: ffff88007fc137a8 RSI: ffff88007fc0db28 RDI: 0001bf00000001be
[   74.332758] RBP: ffffc9000438b8d8 R08: 000000000005008f R09: 00000000000005f9
[   74.333274] R10: ffff88007d001700 R11: ffffffff820a8a4d R12: ffff88007ad96300
[   74.333787] R13: 0000000000000002 R14: ffff880036604000 R15: 000077ff80000000
[   74.334308] FS:  00007fc70d8a7b40(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
[   74.334891] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   74.335314] CR2: 00007fff4144a710 CR3: 000000007ab56000 CR4: 00000000003406f0
[   74.335830] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   74.336373] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   74.336895] Call Trace:
[   74.337086]  skb_release_all+0xd/0x30
[   74.337356]  consume_skb+0x2c/0x90
[   74.337607]  free_unused_bufs+0x1ff/0x270 [virtio_net]
[   74.337988]  ? vp_synchronize_vectors+0x3b/0x60 [virtio_pci]
[   74.338398]  virtnet_xdp+0x21e/0x440 [virtio_net]
[   74.338741]  dev_change_xdp_fd+0x101/0x140
[   74.339048]  do_setlink+0xcf4/0xd20
[   74.339304]  ? symcmp+0xf/0x20
[   74.339529]  ? mls_level_isvalid+0x52/0x60
[   74.339828]  ? mls_range_isvalid+0x43/0x50
[   74.340135]  ? nla_parse+0xa0/0x100
[   74.340400]  rtnl_setlink+0xd4/0x120
[   74.340664]  ? cpumask_next_and+0x30/0x50
[   74.340966]  rtnetlink_rcv_msg+0x7f/0x1f0
[   74.341259]  ? sock_has_perm+0x59/0x60
[   74.341586]  ? napi_consume_skb+0xe2/0x100
[   74.342010]  ? rtnl_newlink+0x890/0x890
[   74.342435]  netlink_rcv_skb+0x92/0xb0
[   74.342846]  rtnetlink_rcv+0x23/0x30
[   74.343277]  netlink_unicast+0x162/0x210
[   74.343677]  netlink_sendmsg+0x2db/0x390
[   74.343968]  sock_sendmsg+0x33/0x40
[   74.344233]  SYSC_sendto+0xee/0x160
[   74.344482]  ? SYSC_bind+0xb0/0xe0
[   74.344806]  ? sock_alloc_file+0x92/0x110
[   74.345106]  ? fd_install+0x20/0x30
[   74.345360]  ? sock_map_fd+0x3f/0x60
[   74.345586]  SyS_sendto+0x9/0x10
[   74.345790]  entry_SYSCALL_64_fastpath+0x1a/0xa9
[   74.346086] RIP: 0033:0x7fc70d1b8f6d
[   74.346312] RSP: 002b:00007fff4144a708 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   74.346785] RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007fc70d1b8f6d
[   74.347244] RDX: 000000000000002c RSI: 00007fff4144a720 RDI: 0000000000000003
[   74.347683] RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
[   74.348544] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff4144bd90
[   74.349082] R13: 0000000000000002 R14: 0000000000000002 R15: 00007fff4144cda0
[   74.349607] Code: 00 00 00 55 48 89 e5 53 48 89 fb 48 8b 7f 58 48 85 ff 74 0e 40 f6 c7 01 74 3d 48 c7 43 58 00 00 00 00 48 8b 7b 68 48 85 ff 74 05 <f0> ff 0f 74 20 48 8b 43 60 48 85 c0 74 14 65 8b 15 f3 ab 8d 7e
[   74.351008] RIP: skb_release_head_state+0x28/0x80 RSP: ffffc9000438b8d0
[   74.351625] ---[ end trace fe6e19fd11cfc80b ]---

Fixes: 2de2f7f4 ("virtio_net: XDP support for adjust_head")
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>