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Message-ID: <5b0b8ffe-75ad-4026-a0e8-8d74992ab7b6@grimberg.me>
Date: Tue, 21 May 2024 16:05:05 +0300
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Subject: Re: Safe to delete rpcrdma.ko loading start-up code
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Chuck Lever III <chuck.lever@oracle.com>,
 Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
 "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
References: <DE53C92C-D16E-4FA7-9C0B-F83F03B1896F@oracle.com>
 <8cc80bdb-9f17-4f44-b2e6-54b36ac85b63@grimberg.me>
 <20240521124306.GE20229@nvidia.com>
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From: Sagi Grimberg <sagi@grimberg.me>
In-Reply-To: <20240521124306.GE20229@nvidia.com>
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On 21/05/2024 15:43, Jason Gunthorpe wrote:
> On Tue, May 21, 2024 at 12:04:02PM +0300, Sagi Grimberg wrote:
>>
>> On 20/05/2024 21:05, Chuck Lever III wrote:
>>> Hi-
>>>
>>> I've tested this with two kinds of systems:
>>>
>>> 1. A system with no physical RDMA devices and no start-up
>>>      scripts to load these modules
>>>
>>> 2. A system with physical RDMA devices and with the start-up
>>>      scripts that load xprtrdma/svcrdma
>>>
>>> In both cases, after doing an "rmmod rpcrdma", I can mount
>>> a "proto=rdma" mount or start the NFS server, and the module
>>> gets reloaded automatically.
>>>
>>> I therefore believe it is safe to delete the code in the
>>> rdma-core start-up scripts that manually load RPC-related
>>> RDMA support. Either the sunrpc.ko module does this, or NFS
>>> user space handles it. There's no need for the rdma-core
>>> scripting.
>> I didn't know that rdma-core does this... it really shouldn't, the
>> mount should (and does) handle it.
> This is new, it didn't used to do this
>
>> I also see that srp(t) and iser(t) are loaded too.. IIRC these are
>> loaded by their userspace counterparts as well (or at least they
>> should).
> And AFIAK, these don't have a way to autoload at all. autoload
> requires the kernel to call request_module..

nvme/nvmet/isert are requested by the kernel. iser is loaded by iscsiadm.
IIRC srp had a userspace daemon loading it.