Re: [PATCH 4/9] nfs: add a freezable_schedule_timeout_unsafe() and use it when waiting to retry LOCK

From: Anna Schumaker <Anna.Schumaker@netapp.com>
To: Jeff Layton <jlayton@redhat.com>, <trond.myklebust@primarydata.com>
Cc: <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH 4/9] nfs: add a freezable_schedule_timeout_unsafe() and use it when waiting to retry LOCK
Date: Thu, 8 Sep 2016 14:20:43 -0400	[thread overview]
Message-ID: <3c94ea23-fd38-be69-2eef-e641c8bb1ff5@Netapp.com> (raw)
In-Reply-To: <1473174760-29859-5-git-send-email-jlayton@redhat.com>

Hi Jeff,

Can you CC the freezer folks on this patch during the second posting?  They'll probably need to at send an ACK for the changes to their include file.

Thanks,
Anna

On 09/06/2016 11:12 AM, Jeff Layton wrote:
> We actually want to use TASK_INTERRUPTIBLE sleeps here. Once the task
> wakes up, if there is a signal pending then we'll be returning an error
> anyway. So, we might as well wake up immediately for non-fatal signals
> as well. That allows us to return to userland more quickly in that case,
> but won't change the error that userland sees.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/nfs/nfs4proc.c       |  3 ++-
>  include/linux/freezer.h | 13 +++++++++++++
>  2 files changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index e3bf95369daf..e9232d71bc64 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -5537,7 +5537,8 @@ int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4
>  static unsigned long
>  nfs4_set_lock_task_retry(unsigned long timeout)
>  {
> -	freezable_schedule_timeout_killable_unsafe(timeout);
> +	set_current_state(TASK_INTERRUPTIBLE);
> +	freezable_schedule_timeout_unsafe(timeout);
>  	timeout <<= 1;
>  	if (timeout > NFS4_LOCK_MAXTIMEOUT)
>  		return NFS4_LOCK_MAXTIMEOUT;
> diff --git a/include/linux/freezer.h b/include/linux/freezer.h
> index dd03e837ebb7..fe31601e7f55 100644
> --- a/include/linux/freezer.h
> +++ b/include/linux/freezer.h
> @@ -197,6 +197,19 @@ static inline long freezable_schedule_timeout(long timeout)
>   * Like schedule_timeout_interruptible(), but should not block the freezer.  Do not
>   * call this with locks held.
>   */
> +static inline long freezable_schedule_timeout_unsafe(long timeout)
> +{
> +	long __retval;
> +	freezer_do_not_count();
> +	__retval = schedule_timeout(timeout);
> +	freezer_count_unsafe();
> +	return __retval;
> +}
> +
> +/*
> + * Like schedule_timeout_interruptible(), but should not block the freezer.  Do not
> + * call this with locks held.
> + */
>  static inline long freezable_schedule_timeout_interruptible(long timeout)
>  {
>  	long __retval;
> 