Groups > comp.os.linux.development.system > #486

sock_create() in kernel

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From	"Mark" <mark_cruzNOTFORSPAM@hotmail.com>
Newsgroups	comp.os.linux.development.system, comp.os.linux.embedded
Subject	sock_create() in kernel
Date	Wed, 19 Dec 2012 10:18:32 -0500
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Cross-posted to 2 groups.

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Hello,

I was looking in to __sock_create() code to get better understanding of the 
kernel's internal machinery and found that the kernel calls try_module_get() 
twice; here is a snippet:

static int __sock_create(struct net *net, int family, int type, int 
protocol, struct socket **res, int kern)
{
   sock = sock_alloc();
   ...
   if (!try_module_get(pf->owner))
      goto out_release;

   err = pf->create(net, sock, protocol);
   ...

   if (!try_module_get(sock->ops->owner))
      goto out_module_busy

   ...
}

Essentially if socket relevant callbacks are in a module, then whenever 
every socket() from the user space will bump the module's reference count 
twice. What's the rationale for such behaviour ?

Thanks.

Mark

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sock_create() in kernel "Mark" <mark_cruzNOTFORSPAM@hotmail.com> - 2012-12-19 10:18 -0500
  Re: sock_create() in kernel Rainer Weikusat <rweikusat@mssgmbh.com> - 2012-12-19 16:06 +0000

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