On 7/3/2023 5:07 PM, Jason Gunthorpe wrote:
On Sat, Jul 01, 2023 at 04:27:23PM +0000, Chuck Lever III wrote:
On Jul 1, 2023, at 12:24 PM, Tom Talpey <tom@xxxxxxxxxx> wrote:
On 6/29/2023 11:16 AM, 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 | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 889b3e4ea980..07bb5ac4019d 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -700,6 +700,21 @@ cma_validate_port(struct ib_device *device, u32 port,
if ((dev_type != ARPHRD_INFINIBAND) && rdma_protocol_ib(device, port))
goto out;
+ /* Linux iWARP devices have but one port */
I don't believe this comment is correct, or necessary. In-tree drivers
exist for several multi-port iWARP devices, and the port bnumber passed
to rdma_protocol_iwarp() and rdma_get_gid_attr() will follow, no?
Then I must have misunderstood what Jason said about the reason
for the rdma_protocol_iwarp() check. He said that we are able to
do this kind of GID lookup because iWARP devices have only a
single port.
Jason?
I don't know alot about iwarp - tom does iwarp really have multiported
*struct ib_device* models? This is different from multiport hw.
I don't see how the iWARP protocol impacts this, but I believe the
cxgb4 provider implements multiport. It sets the ibdev.phys_port_cnt
anyway. Perhaps this is incorrect.
If it is multiport how do the gid tables work across the ports?
Again, not sure how to respond. iWARP doesn't express the gid as a
protocol element. And the iw_cm really doesn't either, although it
does implement a gid-type API I guess. That's local behavior though,
not something that goes on the wire directly.
Maybe I should ask... what does the "Linux iWARP devices have but one
port" actually mean in the comment? Would the code below it not work
if that were not the case? All I'm saying is that the comment seems
to be unnecessary, and confusing.
Tom.
