Messages in this thread Patch in this message | | | Subject | Re: [Patch 3/3] net: reserve ports for applications using fixed port numbers | From | Tetsuo Handa <> | Date | Fri, 9 Apr 2010 22:21:50 +0900 |
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Hello.
Amerigo Wang wrote: > Index: linux-2.6/drivers/infiniband/core/cma.c > =================================================================== > --- linux-2.6.orig/drivers/infiniband/core/cma.c > +++ linux-2.6/drivers/infiniband/core/cma.c > @@ -1980,6 +1980,8 @@ retry: > /* FIXME: add proper port randomization per like inet_csk_get_port */ > do { > ret = idr_get_new_above(ps, bind_list, next_port, &port); > + if (inet_is_reserved_local_port(port)) > + ret = -EAGAIN;
You should not overwrite ret with -EAGAIN when idr_get_new_above() returned -ENOSPC. I don't know about idr, thus I don't know whether
if (!ret && inet_is_reserved_local_port(port)) ret = -EAGAIN;
is correct or not.
> } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL)); > > if (ret) > @@ -2996,10 +2998,13 @@ static int __init cma_init(void) > { > int ret, low, high, remaining; > > - get_random_bytes(&next_port, sizeof next_port); > inet_get_local_port_range(&low, &high); > +again: > + get_random_bytes(&next_port, sizeof next_port); > remaining = (high - low) + 1; > next_port = ((unsigned int) next_port % remaining) + low; > + if (inet_is_reserved_local_port(next_port)) > + goto again; >
You should not unconditionally "goto again;". If all ports were reserved, it will loop forever (CPU stalls).
> cma_wq = create_singlethread_workqueue("rdma_cm"); > if (!cma_wq)
> Index: linux-2.6/net/sctp/socket.c > =================================================================== > --- linux-2.6.orig/net/sctp/socket.c > +++ linux-2.6/net/sctp/socket.c > @@ -5436,6 +5436,8 @@ static long sctp_get_port_local(struct s > rover++; > if ((rover < low) || (rover > high)) > rover = low; > + if (inet_is_reserved_local_port(rover)) > + continue;
This one needs to be
if (inet_is_reserved_local_port(rover)) goto next_nolock;
> index = sctp_phashfn(rover); > head = &sctp_port_hashtable[index]; > sctp_spin_lock(&head->lock);
next: sctp_spin_unlock(&head->lock); +next_nolock: } while (--remaining > 0);
otherwise, it will loop forever if all ports were reserved.
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