Re: [PATCH/RFC] New module refcounting for net_proto_family

[Max Krasnyansky <maxk@qualcomm.com>]

Hmm, no replies. Nobody is interested in this or what ?
I want to get this fixed otherwise I can't fix Bluetooth module
refcounting. 

Max 


On Wed, 2002-12-18 at 07:25, Max Krasnyansky wrote:
> Hi Folks,
> 
> It seems that new module code is going to stay with us at least for a
> while :).
> So it's probably time to start fixing old interfaces to use new
> refcounting scheme.
> 
> Here is a patch for sock_create() and stuff that uses net_proto_family
> interface. Tested with modified af_bluetooth.c and seems to work fine.
> Other families are unaffected for now because their owner field == NULL.
> 
> If people are ok with this aproach I will also fix af_unix and other
> families and push all fixes into my BK tree.
> 
> (URL in case if my mailer messed up spaces
> http://bluez.sourceforge.net/patches/npf_refcnt_patch-2.5.52.gz)
> 
> 
> # This is a BitKeeper generated patch for the following project:
> # Project Name: Linux kernel tree
> # This patch format is intended for GNU patch command version 2.5 or
> higher.
> # This patch includes the following deltas:
> #	           ChangeSet	1.888   -> 1.889  
> #	        net/socket.c	1.39    -> 1.40   
> #	 include/linux/net.h	1.7     -> 1.8    
> #
> # The following is the BitKeeper ChangeSet Log
> # --------------------------------------------
> # 02/12/17	maxk@qualcomm.com	1.889
> # Convert generic socket code to new module refcounting.
> # --------------------------------------------
> #
> diff -Nru a/include/linux/net.h b/include/linux/net.h
> --- a/include/linux/net.h	Tue Dec 17 20:02:04 2002
> +++ b/include/linux/net.h	Tue Dec 17 20:02:04 2002
> @@ -76,6 +76,8 @@
>  
>  	short			type;
>  	unsigned char		passcred;
> +
> +	struct module           *owner;
>  };
>  
>  struct scm_cookie;
> @@ -124,6 +126,8 @@
>  	short	authentication;
>  	short	encryption;
>  	short	encrypt_net;
> +
> +	struct  module *owner;
>  };
>  
>  struct net_proto 
> diff -Nru a/net/socket.c b/net/socket.c
> --- a/net/socket.c	Tue Dec 17 20:02:04 2002
> +++ b/net/socket.c	Tue Dec 17 20:02:04 2002
> @@ -470,6 +470,8 @@
>  
>  	sock = SOCKET_I(inode);
>  
> +	sock->owner = NULL;
> +	
>  	inode->i_mode = S_IFSOCK|S_IRWXUGO;
>  	inode->i_sock = 1;
>  	inode->i_uid = current->fsuid;
> @@ -517,6 +519,8 @@
>  		return;
>  	}
>  	sock->file=NULL;
> +
> +	module_put(sock->owner);
>  }
>  
>  static int __sock_sendmsg(struct kiocb *iocb, struct socket *sock,
> struct msghdr *msg, int size)
> @@ -964,8 +968,9 @@
>  
>  int sock_create(int family, int type, int protocol, struct socket
> **res)
>  {
> -	int i;
> +	struct net_proto_family *npf;
>  	struct socket *sock;
> +	int err;
>  
>  	/*
>  	 *	Check protocol is in range
> @@ -990,14 +995,8 @@
>  	}
>  		
>  #if defined(CONFIG_KMOD) && defined(CONFIG_NET)
> -	/* Attempt to load a protocol module if the find failed. 
> -	 * 
> -	 * 12/09/1996 Marcin: But! this makes REALLY only sense, if the user 
> -	 * requested real, full-featured networking support upon
> configuration.
> -	 * Otherwise module support will break!
> -	 */
> -	if (net_families[family]==NULL)
> -	{
> +	/* Attempt to load a protocol module if the find failed. */
> +	if (net_families[family]==NULL) {
>  		char module_name[30];
>  		sprintf(module_name,"net-pf-%d",family);
>  		request_module(module_name);
> @@ -1005,29 +1004,31 @@
>  #endif
>  
>  	net_family_read_lock();
> -	if (net_families[family] == NULL) {
> -		i = -EAFNOSUPPORT;
> +
> +	npf = net_families[family];
> +	if (!npf || !try_module_get(npf->owner)) {
> +		err = -EAFNOSUPPORT;
>  		goto out;
>  	}
> +	
> +	/*
> +	 * Allocate the socket and allow the family to set things up. if
> +	 * the protocol is 0, the family is instructed to select an
> appropriate
> +	 * default.
> + 	 */
>  
> -/*
> - *	Allocate the socket and allow the family to set things up. if
> - *	the protocol is 0, the family is instructed to select an appropriate
> - *	default.
> - */
> -
> -	if (!(sock = sock_alloc())) 
> -	{
> +	sock = sock_alloc();
> +	if (!sock) {
>  		printk(KERN_WARNING "socket: no more sockets\n");
> -		i = -ENFILE;		/* Not exactly a match, but its the
> +		err = -ENFILE;		/* Not exactly a match, but its the
>  					   closest posix thing */
>  		goto out;
>  	}
>  
>  	sock->type  = type;
> +	sock->owner = npf->owner;
>  
> -	if ((i = net_families[family]->create(sock, protocol)) < 0) 
> -	{
> +	if ((err = npf->create(sock, protocol)) < 0) {
>  		sock_release(sock);
>  		goto out;
>  	}
> @@ -1036,7 +1037,7 @@
>  
>  out:
>  	net_family_read_unlock();
> -	return i;
> +	return err;
>  }
>  
>  asmlinkage long sys_socket(int family, int type, int protocol)
> @@ -1201,6 +1202,9 @@
>  	newsock->type = sock->type;
>  	newsock->ops = sock->ops;
>  
> +	try_module_get(sock->owner);
> +	newsock->owner = sock->owner;
> +	
>  	err = sock->ops->accept(sock, newsock, sock->file->f_flags);
>  	if (err < 0)
>  		goto out_release;
-- 
Max Krasnyansky <maxk@qualcomm.com>
Qualcomm