Hi Haris,
On 11/14/22 9:36 PM, Haris Iqbal wrote:
The change was introduced due to a bug report, you can follow the
discussion here for the history and reason:
https://lore.kernel.org/linux-rdma/20200617103732.10356-1-haris.iqbal@xxxxxxxxxxxxxxx/
Thanks for the link.
I probably missed something but I don't know how rnbd_server module can be
initialized before cma module since we have the dependency chain as
follows.
Hi Guoqing,
One of the ways this was happening was, when one builds the RNBD/RTRS
module into the kernel bzImage and then boots up the kernel. Depending
on the module init sequence, if the RNBD/RTRS modules are picked
before the RDMA one, then this issue would hit.
This is what I missed since I usually build RNBD with M.
With the changes, RNBD/RTRS just register itself to ib. If any devices
are present at that moment, for example when the module is modprob'ed
later into the kernel, then .add gets called through
ib_register_client. If no devices are present, for example in case if
the module is built into the bzImage, and is inserted before RDMA
module, then ib_register_client simply registers RTRS, and returns
without calling .add
Now, when RDMA gets initialized, and it detects devices, then .add is
called for each device, which will land into rtrs_srv_add_one
Thanks for the details! It explains well why ib_register_client is added,
and rtrs_srv_rdma_init is guaranteed to be called once too. Will drop
this one.
Thanks,
Guoqings
