> On Jun 22, 2023, at 11:13 AM, Jason Gunthorpe <jgg@xxxxxxxxxx> wrote:
>
> On Wed, Jun 14, 2023 at 10:00:59AM -0400, Chuck Lever wrote:
>> From: Chuck Lever <chuck.lever@xxxxxxxxxx>
>>
>> We would like to enable the use of siw on top of a VPN that is
>> constructed and managed via a tun device. That hasn't worked up
>> until now because ARPHRD_NONE devices (such as tun devices) have
>> no GID for the RDMA/core to look up.
>>
>> But it turns out that the egress device has already been picked for
>> us -- no GID is necessary. addr_handler() just has to do the right
>> thing with it.
>>
>> Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> drivers/infiniband/core/cma.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
>> index a1756ed1faa1..50b8da2c4720 100644
>> --- a/drivers/infiniband/core/cma.c
>> +++ b/drivers/infiniband/core/cma.c
>> @@ -700,6 +700,19 @@ cma_validate_port(struct ib_device *device, u32 port,
>> if ((dev_type != ARPHRD_INFINIBAND) && rdma_protocol_ib(device, port))
>> goto out;
>>
>> + if (rdma_protocol_iwarp(device, port)) {
>> + sgid_attr = rdma_get_gid_attr(device, port, 0);
>> + if (IS_ERR(sgid_attr))
>> + goto out;
>> +
>> + /* XXX: I don't think this is RCU-safe, but does it need to be? */
>
> Maybe for subtle reasons related to iwarp it is safe, but it should
> make a lockdep splat since you are not holding rcu?
>
> Remove the comment and do a rcu_lock/unlock around this and the deref
Done, v4 posted.
The reason I was unsure:
CC drivers/infiniband/core/roce_gid_mgmt.o
CHECK /home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:292:23: warning: incorrect type in assignment (different address spaces)
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:292:23: expected struct net_device [noderef] __rcu *[addressable] ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:292:23: got struct net_device *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:386:48: warning: incorrect type in initializer (different address spaces)
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:386:48: expected struct net_device [noderef] __rcu *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:386:48: got struct net_device *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:811:48: warning: incorrect type in argument 2 (different address spaces)
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:811:48: expected void *filter_cookie
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:811:48: got struct net_device [noderef] __rcu *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:814:31: warning: incorrect type in argument 1 (different address spaces)
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:814:31: expected struct net_device *dev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:814:31: got struct net_device [noderef] __rcu *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:851:31: warning: incorrect type in assignment (different address spaces)
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:851:31: expected struct net_device [noderef] __rcu *ndev
/home/cel/src/linux/linux/drivers/infiniband/core/roce_gid_mgmt.c:851:31: got struct net_device *ndev
--
Chuck Lever
