Some QPs (e.g. XRC QP) are not tracked in kernel, in this case they have
an invalid res and should not be bound to any dynamically-allocated
counter in auto mode.

This fixes below call trace:
BUG: kernel NULL pointer dereference, address: 0000000000000390
PGD 80000001a7233067 P4D 80000001a7233067 PUD 1a7215067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 2 PID: 24822 Comm: ibv_xsrq_pingpo Not tainted 5.4.0-rc5+ #21
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014
RIP: 0010:rdma_counter_bind_qp_auto+0x142/0x270 [ib_core]
Code: e1 48 85 c0 48 89 c2 0f 84 bc 00 00 00 49 8b 06 48 39 42 48 75 d6 40 3a aa 90 00 00 00 75 cd 49 8b 86 00 01 00 00 48 8b 4a 28 <8b> 80 90 03 00 00 39 81 90 03 00 00 75 b4 85 c0 74 b0 48 8b 04 24
RSP: 0018:ffffc900003f39c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88820020ec00 RSI: 0000000000000004 RDI: ffffffffffffffc0
RBP: 0000000000000001 R08: ffff888224149ff0 R09: ffffc900003f3968
R10: ffffffffffffffff R11: ffff8882249c5848 R12: ffffffffffffffff
R13: ffff88821d5aca50 R14: ffff8881f7690800 R15: ffff8881ff890000
FS:  00007fe53a3e1740(0000) GS:ffff888237b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000390 CR3: 00000001a7292006 CR4: 00000000003606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 _ib_modify_qp+0x3a4/0x3f0 [ib_core]
 ? lookup_get_idr_uobject.part.8+0x23/0x40 [ib_uverbs]
 modify_qp+0x322/0x3e0 [ib_uverbs]
 ib_uverbs_modify_qp+0x43/0x70 [ib_uverbs]
 ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xb1/0xf0 [ib_uverbs]
 ib_uverbs_run_method+0x6be/0x760 [ib_uverbs]
 ? uverbs_disassociate_api+0xd0/0xd0 [ib_uverbs]
 ib_uverbs_cmd_verbs+0x18d/0x3a0 [ib_uverbs]
 ? get_acl+0x1a/0x120
 ? __alloc_pages_nodemask+0x15d/0x2c0
 ib_uverbs_ioctl+0xa7/0x110 [ib_uverbs]
 do_vfs_ioctl+0xa5/0x610
 ksys_ioctl+0x60/0x90
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x48/0x110
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 99fa331d ("RDMA/counter: Add "auto" configuration mode support")
Signed-off-by: Mark Zhang <markz@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Ido Kalir <idok@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20191212091214.315005-2-leon@kernel.orgSigned-off-by: Doug Ledford <dledford@redhat.com>