Re: [PATCH] sunrpc: remove unnecessary svc_xprt_put

J. Bruce Fields
2010-02-26T22:43:40Z

On Sat, Feb 27, 2010 at 09:33:40AM +1100, Neil Brown wrote:
>
> [I found this while looking for the current refcount problem
> that triggers a warning in svc_recv. This isn't that bug
> but is a different refcount bug - NB]
>
> The 'struct svc_deferred_req's on the xpt_deferred queue do not
> own a reference to the owning xprt. This is seen in svc_revisit
> which is where things are added to this queue. dr->xprt is set to
> NULL and the reference to the xprt it put.
>
> So when this list is cleaned up in svc_delete_xprt, we mustn't
> put the reference.
>
> Also, replace the 'for' with a 'while' which is arguably
> simpler and more likely to compile efficiently.

OK, thanks, queuing up for 2.6.34 and stable.

--b.

>
> Cc: Tom Tucker <tom@opengridcomputing.com>
> Signed-off-by: NeilBrown <neilb@suse.de>
>
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index 7d1f9e9..4f30336 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -889,11 +889,8 @@ void svc_delete_xprt(struct svc_xprt *xprt)
> if (test_bit(XPT_TEMP, &xprt->xpt_flags))
> serv->sv_tmpcnt--;
>
> - for (dr = svc_deferred_dequeue(xprt); dr;
> - dr = svc_deferred_dequeue(xprt)) {
> - svc_xprt_put(xprt);
> + while ((dr = svc_deferred_dequeue(xprt)) != NULL)
> kfree(dr);
> - }
>
> svc_xprt_put(xprt);
> spin_unlock_bh(&serv->sv_lock);