RDMA/cma: Fix kmemleak in rdma_core observed during blktests nvme/rdma use siw

When running blktests nvme/rdma, the following kmemleak issue will appear.

kmemleak: Kernel memory leak detector initialized (mempool available:36041)
kmemleak: Automatic memory scanning thread started
kmemleak: 2 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
kmemleak: 8 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
kmemleak: 17 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

unreferenced object 0xffff88855da53400 (size 192):
  comm "rdma", pid 10630, jiffies 4296575922
  hex dump (first 32 bytes):
    37 00 00 00 00 00 00 00 c0 ff ff ff 1f 00 00 00  7...............
    10 34 a5 5d 85 88 ff ff 10 34 a5 5d 85 88 ff ff  .4.].....4.]....
  backtrace (crc 47f66721):
    [<ffffffff911251bd>] kmalloc_trace+0x30d/0x3b0
    [<ffffffffc2640ff7>] alloc_gid_entry+0x47/0x380 [ib_core]
    [<ffffffffc2642206>] add_modify_gid+0x166/0x930 [ib_core]
    [<ffffffffc2643468>] ib_cache_update.part.0+0x6d8/0x910 [ib_core]
    [<ffffffffc2644e1a>] ib_cache_setup_one+0x24a/0x350 [ib_core]
    [<ffffffffc263949e>] ib_register_device+0x9e/0x3a0 [ib_core]
    [<ffffffffc2a3d389>] 0xffffffffc2a3d389
    [<ffffffffc2688cd8>] nldev_newlink+0x2b8/0x520 [ib_core]
    [<ffffffffc2645fe3>] rdma_nl_rcv_msg+0x2c3/0x520 [ib_core]
    [<ffffffffc264648c>]
rdma_nl_rcv_skb.constprop.0.isra.0+0x23c/0x3a0 [ib_core]
    [<ffffffff9270e7b5>] netlink_unicast+0x445/0x710
    [<ffffffff9270f1f1>] netlink_sendmsg+0x761/0xc40
    [<ffffffff9249db29>] __sys_sendto+0x3a9/0x420
    [<ffffffff9249dc8c>] __x64_sys_sendto+0xdc/0x1b0
    [<ffffffff92db0ad3>] do_syscall_64+0x93/0x180
    [<ffffffff92e00126>] entry_SYSCALL_64_after_hwframe+0x71/0x79

The root cause: rdma_put_gid_attr is not called when sgid_attr is set
to ERR_PTR(-ENODEV).

Reported-and-tested-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/all/19bf5745-1b3b-4b8a-81c2-20d945943aaf@linux.dev/T/
Fixes: f8ef1be ("RDMA/cma: Avoid GID lookups on iWARP devices")
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Link: https://lore.kernel.org/r/20240510211247.31345-1-yanjun.zhu@linux.dev
Signed-off-by: Leon Romanovsky <leon@kernel.org>

Author: zhuyj

drivers/infiniband/core/cma.c

@@ -715,8 +715,10 @@ cma_validate_port(struct ib_device *device, u32 port,
 		rcu_read_lock();
 		ndev = rcu_dereference(sgid_attr->ndev);
 		if (!net_eq(dev_net(ndev), dev_addr->net) ||
-		    ndev->ifindex != bound_if_index)
+		    ndev->ifindex != bound_if_index) {
+			rdma_put_gid_attr(sgid_attr);
 			sgid_attr = ERR_PTR(-ENODEV);
+		}
 		rcu_read_unlock();
 		goto out;
 	}