net/smc: Fix NULL pointer dereference in smc_pnet_find_ib()

stable inclusion
from stable-v5.10.112
commit 35b91e49bc80ca944a8679c3b139ddaf2f8eea0f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=35b91e49bc80ca944a8679c3b139ddaf2f8eea0f



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[ Upstream commit d22f4f97 ]

dev_name() was called with dev.parent as argument but without to
NULL-check it before.
Solve this by checking the pointer before the call to dev_name().

Fixes: af5f60c7 ("net/smc: allow PCI IDs as ib device names in the pnet table")
Reported-by:  <syzbot+03e3e228510223dabd34@syzkaller.appspotmail.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>