Re: [PATCH 09/18] cifs: clean up sync_mid_result

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Mon, 20 Dec 2010 16:57:41 +0530
Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org> wrote:

> On 12/17/2010 08:38 PM, Jeff Layton wrote:
> > Make it use a switch statement based on the value of the midStatus. If
> > the resp_buf is set, then MID_RESPONSE_RECEIVED is too.
> > 
> > Signed-off-by: Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> >  fs/cifs/transport.c |   35 ++++++++++++++++++-----------------
> >  1 files changed, 18 insertions(+), 17 deletions(-)
> > 
> > diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> > index f65cdec..6abd144 100644
> > --- a/fs/cifs/transport.c
> > +++ b/fs/cifs/transport.c
> > @@ -363,28 +363,29 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
> >  {
> >  	int rc = 0;
> >  
> > -	spin_lock(&GlobalMid_Lock);
> > +	cFYI(1, "%s: cmd=%d mid=%d state=%d", __func__, mid->command,
> > +		mid->mid, mid->midState);
> >  
> > -	if (mid->resp_buf) {
> > +	spin_lock(&GlobalMid_Lock);
> > +	switch (mid->midState) {
> > +	case MID_RESPONSE_RECEIVED:
> >  		spin_unlock(&GlobalMid_Lock);
> >  		return rc;
> > -	}
> > -
> > -	cERROR(1, "No response to cmd %d mid %d", mid->command, mid->mid);
> > -	if (mid->midState == MID_REQUEST_SUBMITTED) {
> > -		if (server->tcpStatus == CifsExiting)
> > +	case MID_REQUEST_SUBMITTED:
> > +		/* socket is going down, reject all calls */
> > +		if (server->tcpStatus == CifsExiting) {
> > +			cERROR(1, "%s: canceling mid=%d cmd=0x%x state=%d",
> > +			       __func__, mid->mid, mid->command, mid->midState);
> >  			rc = -EHOSTDOWN;
> > -		else
> > -			mid->midState = MID_RETRY_NEEDED;
> > -	}
> 
> When midState is MID_REQUEST_SUBMITTED and tcpStatus is not CifsExiting,
> the old code used to set midState to MID_RETRY_NEEDED. This is not set
> now - is this intentional?
> 

I don't think it matters much. wait_for_response does this:

        error = wait_event_killable(server->response_q,
                                    midQ->midState != MID_REQUEST_SUBMITTED);

...so you can only get out of that wait with MID_REQUEST_SUBMITTED by
fatal signal. At that point, the caller is going to do send the cancel
and return without calling handle_mid_result.

So TBH, I think that this MID_REQUEST_SUBMITTED clause is going to be
unused, but we could reset the value to MID_RETRY_NEEDED if we think
it'll be better for future-proofness.


> > -	if (rc != -EHOSTDOWN) {
> > -		if (mid->midState == MID_RETRY_NEEDED) {
> > -			rc = -EAGAIN;
> > -			cFYI(1, "marking request for retry");
> > -		} else {
> > -			rc = -EIO;
> > +			break;
> >  		}
> > +	case MID_RETRY_NEEDED:
> > +		rc = -EAGAIN;
> > +		break;
> > +	default:
> > +		cERROR(1, "%s: invalid mid state mid=%d state=%d", __func__,
> > +			mid->mid, mid->midState);
> > +		rc = -EIO;
> >  	}
> >  	spin_unlock(&GlobalMid_Lock);
> >  
> 
> 


-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>