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From: Jason Gunthorpe <jgg@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	linux-rdma@vger.kernel.org,
	syzbot+dc3dfba010d7671e05f5@syzkaller.appspotmail.com
Subject: Re: [PATCH rc] RDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests
Date: Thu, 23 Sep 2021 08:45:57 -0300	[thread overview]
Message-ID: <20210923114557.GI964074@nvidia.com> (raw)
In-Reply-To: <YUwVUjrqT2PyVEO7@unreal>

On Thu, Sep 23, 2021 at 08:49:06AM +0300, Leon Romanovsky wrote:
> On Wed, Sep 22, 2021 at 11:41:19AM -0300, Jason Gunthorpe wrote:
> > On Wed, Sep 22, 2021 at 11:01:39AM +0300, Leon Romanovsky wrote:
> > 
> > > > +			/* The FSM can return back to RDMA_CM_ADDR_BOUND after
> > > > +			 * rdma_resolve_ip() is called, eg through the error
> > > > +			 * path in addr_handler. If this happens the existing
> > > > +			 * request must be canceled before issuing a new one.
> > > > +			 */
> > > > +			if (id_priv->used_resolve_ip)
> > > > +				rdma_addr_cancel(&id->route.addr.dev_addr);
> > > > +			else
> > > > +				id_priv->used_resolve_ip = 1;
> > > 
> > > Why don't you never clear this field?
> > 
> > The only case where it can be cleared is if we have called
> > rdma_addr_cancel(), and since this is the only place that does it and
> > immediately calls rdma_resolve_ip() again, there is no reason to ever
> > clear it.
> 
> IMHO, it is better to clear instead to rely on "the only place" semantic.

Then the code looks really silly:

	if (id_priv->used_resolve_ip) {
		rdma_addr_cancel(&id->route.addr.dev_addr);
                id_priv->used_resolve_ip = 0;
        }
        id_priv->used_resolve_ip = 1;

Jason

  reply	other threads:[~2021-09-23 11:46 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-16 18:34 [PATCH rc] RDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests Jason Gunthorpe
2021-09-22  8:01 ` Leon Romanovsky
2021-09-22  9:38   ` Haakon Bugge
2021-09-22 14:44     ` Jason Gunthorpe
2021-09-22 14:41   ` Jason Gunthorpe
2021-09-23  5:49     ` Leon Romanovsky
2021-09-23 11:45       ` Jason Gunthorpe [this message]
2021-09-23 18:15         ` Leon Romanovsky
2021-09-23 20:03           ` Jason Gunthorpe
2021-09-23 23:17             ` Leon Romanovsky

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