On Fri, Nov 17 2017, Joshua Watt wrote:
> The flag causes any new tasks that are queued to exit immediately with
> -EIO instead of executing. This will allow clients (particularly NFS) to
> prevents these task from delaying shutdown of the RPC session longer
> than necessary.
>
> Signed-off-by: Joshua Watt <JPEWhacker@xxxxxxxxx>
> ---
> include/linux/sunrpc/clnt.h | 1 +
> net/sunrpc/clnt.c | 5 ++---
> net/sunrpc/sched.c | 3 +++
> 3 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
> index 71c237e8240e..d36dc529fdf0 100644
> --- a/include/linux/sunrpc/clnt.h
> +++ b/include/linux/sunrpc/clnt.h
> @@ -54,6 +54,7 @@ struct rpc_clnt {
> cl_noretranstimeo: 1,/* No retransmit timeouts */
> cl_autobind : 1,/* use getport() */
> cl_chatty : 1;/* be verbose */
> + atomic_t cl_kill_new_tasks; /* Kill all new tasks */
It looks a little weird that this is an atomic_t.
Looking further ahead, it seems that it is a counter of threads that
have request new tasks be killed.
It might help to make that clear, at least in a comment.
>
> struct rpc_rtt * cl_rtt; /* RTO estimator data */
> const struct rpc_timeout *cl_timeout; /* Timeout strategy */
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index df4ecb042ebe..d5eedabf0b4d 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -626,6 +626,8 @@ static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
> new->cl_noretranstimeo = clnt->cl_noretranstimeo;
> new->cl_discrtry = clnt->cl_discrtry;
> new->cl_chatty = clnt->cl_chatty;
> + atomic_set(&new->cl_kill_new_tasks,
> + atomic_read(&clnt->cl_kill_new_tasks));
However ... as it is a counter, it isn't clear that copying the counter
makes sense, and the new counter will never get decremented.
Maybe __rpc_clone_client() should fail if ->cl_kill_new_tasks > 0 ??
Thanks,
NeilBrown
> return new;
>
> out_err:
> @@ -818,9 +820,6 @@ void rpc_killall_tasks(struct rpc_clnt *clnt)
> {
> struct rpc_task *rovr;
>
> -
> - if (list_empty(&clnt->cl_tasks))
> - return;
> dprintk("RPC: killing all tasks for client %p\n", clnt);
> /*
> * Spin lock all_tasks to prevent changes...
> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> index 0cc83839c13c..e70034e19ccd 100644
> --- a/net/sunrpc/sched.c
> +++ b/net/sunrpc/sched.c
> @@ -748,6 +748,9 @@ static void __rpc_execute(struct rpc_task *task)
> dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
> task->tk_pid, task->tk_flags);
>
> + if (atomic_read(&task->tk_client->cl_kill_new_tasks))
> + rpc_exit(task, -EIO);
> +
> WARN_ON_ONCE(RPC_IS_QUEUED(task));
> if (RPC_IS_QUEUED(task))
> return;
> --
> 2.13.6
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