Messages in this thread | | | Date | Tue, 13 Apr 2010 16:48:32 +0800 | From | Cong Wang <> | Subject | Re: [Patch 3/3] net: reserve ports for applications using fixed port numbers |
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Cong Wang wrote: > Tetsuo Handa wrote: >> Hello. >> >>> --- 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 (!ret && inet_is_reserved_local_port(port)) >>> + ret = -EAGAIN; >>> } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL)); >>> >>> if (ret) >>> >> I think above part is wrong. Below program > ... >> This result suggests that above loop will continue until idr_pre_get() fails >> due to out of memory if all ports were reserved. >> >> Also, if idr_get_new_above() returned 0, bind_list (which is a kmalloc()ed >> pointer) is already installed into a free slot (see comment on >> idr_get_new_above_int()). Thus, simply calling idr_get_new_above() again will >> install the same pointer into multiple slots. I guess it will malfunction later. > > Thanks for testing! > > How about: > > + if (!ret && inet_is_reserved_local_port(port)) > + ret = -EBUSY; > > ? So that it will break the loop and return error. >
Or use the similar trick:
int tries = 10; ...
if(!ret && inet_is_reserved_local_port(port)) { if (tries--) ret = -EAGAIN; else ret = -EBUSY; }
Any comments?
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