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

Max Krasnyansky
2002-12-19T18:21:42Z

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