[Cyrill Gorcunov - Sat, Jan 10, 2009 at 12:22:58PM +0300]
| [Cyrill Gorcunov - Fri, Jan 09, 2009 at 10:51:58PM +0300]
| | - Each namespace contain ppp channels and units separately
| |   with appropriate locks
| | 
| | CC: Paul Mackerras <pau...@samba.org>
| | Signed-off-by: Cyrill Gorcunov <gorcu...@openvz.org>
| ...
| 
| Please ignore this one -- I forgot to update
| ppp_init while was porting the patch. Will
| fix.
| 
|               - Cyrill -

ok, here is an updated version

                - Cyrill -
---
From: Cyrill Gorcunov <gorcu...@gmail.com>
Subecjt: [RFC] net: ppp_generic - introduce net-namespace functionality

- Each namespace contain ppp channels and units separately
  with appropriate locks

CC: Paul Mackerras <pau...@samba.org>
Signed-off-by: Cyrill Gorcunov <gorcu...@openvz.org>
---
 drivers/net/ppp_generic.c |  279 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 199 insertions(+), 80 deletions(-)

Index: linux-2.6.git/drivers/net/ppp_generic.c
===================================================================
--- linux-2.6.git.orig/drivers/net/ppp_generic.c
+++ linux-2.6.git/drivers/net/ppp_generic.c
@@ -49,6 +49,10 @@
 #include <net/slhc_vj.h>
 #include <asm/atomic.h>
 
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+
 #define PPP_VERSION    "2.4.2"
 
 /*
@@ -89,6 +93,8 @@ struct ppp_file {
 #define PF_TO_PPP(pf)          PF_TO_X(pf, struct ppp)
 #define PF_TO_CHANNEL(pf)      PF_TO_X(pf, struct channel)
 
+struct ppp_net;
+
 /*
  * Data structure describing one ppp unit.
  * A ppp unit corresponds to a ppp network interface device
@@ -131,6 +137,7 @@ struct ppp {
        struct sock_filter *active_filter;/* filter for pkts to reset idle */
        unsigned pass_len, active_len;
 #endif /* CONFIG_PPP_FILTER */
+       struct net      *ppp_net;       /* the net we belong to */
 };
 
 /*
@@ -173,25 +180,36 @@ struct channel {
  * channel.downl.
  */
 
-/*
- * all_ppp_mutex protects the all_ppp_units mapping.
- * It also ensures that finding a ppp unit in the all_ppp_units map
- * and updating its file.refcnt field is atomic.
- */
-static DEFINE_MUTEX(all_ppp_mutex);
 static atomic_t ppp_unit_count = ATOMIC_INIT(0);
-static DEFINE_IDR(ppp_units_idr);
+static atomic_t channel_count = ATOMIC_INIT(0);
 
 /*
- * all_channels_lock protects all_channels and last_channel_index,
- * and the atomicity of find a channel and updating its file.refcnt
- * field.
+ * per net-namespace data for this module
  */
-static DEFINE_SPINLOCK(all_channels_lock);
-static LIST_HEAD(all_channels);
-static LIST_HEAD(new_channels);
-static int last_channel_index;
-static atomic_t channel_count = ATOMIC_INIT(0);
+static unsigned int ppp_net_id;
+struct ppp_net {
+       /* units to ppp mapping */
+       struct idr units_idr;
+
+       /* channels */
+       struct list_head all_channels;
+       struct list_head new_channels;
+       int last_channel_index;
+
+       /*
+        * all_ppp_mutex protects the units_idr mapping.
+        * It also ensures that finding a ppp unit in the units_idr
+        * map and updating its file.refcnt field is atomic.
+        */
+       struct mutex all_ppp_mutex;
+
+       /*
+        * all_channels_lock protects all_channels and
+        * last_channel_index, and the atomicity of find
+        * a channel and updating its file.refcnt field.
+        */
+       spinlock_t all_channels_lock;
+};
 
 /* Get the PPP protocol number from a skb */
 #define PPP_PROTO(skb) (((skb)->data[0] << 8) + (skb)->data[1])
@@ -240,21 +258,28 @@ static void ppp_ccp_peek(struct ppp *ppp
 static void ppp_ccp_closed(struct ppp *ppp);
 static struct compressor *find_compressor(int type);
 static void ppp_get_stats(struct ppp *ppp, struct ppp_stats *st);
-static struct ppp *ppp_create_interface(int unit, int *retp);
+static struct ppp *ppp_create_interface(struct net *net, int unit, int *retp);
 static void init_ppp_file(struct ppp_file *pf, int kind);
 static void ppp_shutdown_interface(struct ppp *ppp);
 static void ppp_destroy_interface(struct ppp *ppp);
-static struct ppp *ppp_find_unit(int unit);
-static struct channel *ppp_find_channel(int unit);
+static struct channel *ppp_find_channel(struct net *net, int unit);
 static int ppp_connect_channel(struct channel *pch, int unit);
 static int ppp_disconnect_channel(struct channel *pch);
 static void ppp_destroy_channel(struct channel *pch);
-static int unit_get(struct idr *p, void *ptr);
-static void unit_put(struct idr *p, int n);
-static void *unit_find(struct idr *p, int n);
+static int unit_get(struct net *net, void *ptr);
+static void unit_put(struct net *net, int n);
+static void *unit_find(struct net *net, int n);
 
 static struct class *ppp_class;
 
+/* per net-namespace data */
+static inline struct ppp_net *ppp_pernet(struct net *net)
+{
+       BUG_ON(!net);
+
+       return net_generic(net, ppp_net_id);
+}
+
 /* Translates a PPP protocol number to a NP index (NP == network protocol) */
 static inline int proto_to_npindex(int proto)
 {
@@ -343,6 +368,7 @@ static int ppp_open(struct inode *inode,
         */
        if (!capable(CAP_NET_ADMIN))
                return -EPERM;
+
        return 0;
 }
 
@@ -768,6 +794,7 @@ static int ppp_unattached_ioctl(struct p
        int unit, err = -EFAULT;
        struct ppp *ppp;
        struct channel *chan;
+       struct ppp_net *pn;
        int __user *p = (int __user *)arg;
 
        lock_kernel();
@@ -776,7 +803,7 @@ static int ppp_unattached_ioctl(struct p
                /* Create a new ppp unit */
                if (get_user(unit, p))
                        break;
-               ppp = ppp_create_interface(unit, &err);
+               ppp = ppp_create_interface(current->nsproxy->net_ns, unit, 
&err);
                if (!ppp)
                        break;
                file->private_data = &ppp->file;
@@ -791,29 +818,31 @@ static int ppp_unattached_ioctl(struct p
                /* Attach to an existing ppp unit */
                if (get_user(unit, p))
                        break;
-               mutex_lock(&all_ppp_mutex);
+               pn = ppp_pernet(current->nsproxy->net_ns);
+               mutex_lock(&pn->all_ppp_mutex);
                err = -ENXIO;
-               ppp = ppp_find_unit(unit);
+               ppp = unit_find(current->nsproxy->net_ns, unit);
                if (ppp) {
                        atomic_inc(&ppp->file.refcnt);
                        file->private_data = &ppp->file;
                        err = 0;
                }
-               mutex_unlock(&all_ppp_mutex);
+               mutex_unlock(&pn->all_ppp_mutex);
                break;
 
        case PPPIOCATTCHAN:
                if (get_user(unit, p))
                        break;
-               spin_lock_bh(&all_channels_lock);
+               pn = ppp_pernet(current->nsproxy->net_ns);
+               spin_lock_bh(&pn->all_channels_lock);
                err = -ENXIO;
-               chan = ppp_find_channel(unit);
+               chan = ppp_find_channel(current->nsproxy->net_ns, unit);
                if (chan) {
                        atomic_inc(&chan->file.refcnt);
                        file->private_data = &chan->file;
                        err = 0;
                }
-               spin_unlock_bh(&all_channels_lock);
+               spin_unlock_bh(&pn->all_channels_lock);
                break;
 
        default:
@@ -833,6 +862,54 @@ static const struct file_operations ppp_
        .release        = ppp_release
 };
 
+static __net_init int ppp_init_net(struct net *net)
+{
+       struct ppp_net *pn;
+       int err;
+
+       pn = kzalloc(sizeof(*pn), GFP_KERNEL);
+       if (!pn)
+               return -ENOMEM;
+
+       idr_init(&pn->units_idr);
+
+       INIT_LIST_HEAD(&pn->all_channels);
+       INIT_LIST_HEAD(&pn->new_channels);
+
+       mutex_init(&pn->all_ppp_mutex);
+       spin_lock_init(&pn->all_channels_lock);
+
+       err = net_assign_generic(net, ppp_net_id, pn);
+       if (err) {
+               kfree(pn);
+               return err;
+       }
+
+       try_module_get(THIS_MODULE);
+       return 0;
+}
+
+static __net_exit void ppp_exit_net(struct net *net)
+{
+       struct ppp_net *pn;
+
+       pn = net_generic(net, ppp_net_id);
+       idr_destroy(&pn->units_idr);
+       /*
+        * if someone has cached our net then
+        * further net_generic call will return NULL
+        */
+       net_assign_generic(net, ppp_net_id, NULL);
+       kfree(pn);
+
+       module_put(THIS_MODULE);
+}
+
+static __net_initdata struct pernet_operations ppp_net_ops = {
+       .init = ppp_init_net,
+       .exit = ppp_exit_net,
+};
+
 #define PPP_MAJOR      108
 
 /* Called at boot time if ppp is compiled into the kernel,
@@ -842,25 +919,36 @@ static int __init ppp_init(void)
        int err;
 
        printk(KERN_INFO "PPP generic driver version " PPP_VERSION "\n");
-       err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
-       if (!err) {
-               ppp_class = class_create(THIS_MODULE, "ppp");
-               if (IS_ERR(ppp_class)) {
-                       err = PTR_ERR(ppp_class);
-                       goto out_chrdev;
-               }
-               device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL,
-                             "ppp");
+
+       err = register_pernet_gen_device(&ppp_net_id, &ppp_net_ops);
+       if (err) {
+               printk(KERN_ERR "failed to register PPP pernet device (%d)\n", 
err);
+               goto out;
        }
 
-out:
-       if (err)
+       err = register_chrdev(PPP_MAJOR, "ppp", &ppp_device_fops);
+       if (err) {
                printk(KERN_ERR "failed to register PPP device (%d)\n", err);
-       return err;
+               goto out_net;
+       }
+
+       ppp_class = class_create(THIS_MODULE, "ppp");
+       if (IS_ERR(ppp_class)) {
+               err = PTR_ERR(ppp_class);
+               goto out_chrdev;
+       }
+
+       /* not a big deal if we fail here :-) */
+       device_create(ppp_class, NULL, MKDEV(PPP_MAJOR, 0), NULL, "ppp");
+
+       return 0;
 
 out_chrdev:
        unregister_chrdev(PPP_MAJOR, "ppp");
-       goto out;
+out_net:
+       unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
+out:
+       return err;
 }
 
 /*
@@ -1992,10 +2080,14 @@ int
 ppp_register_channel(struct ppp_channel *chan)
 {
        struct channel *pch;
+       struct ppp_net *pn;
 
        pch = kzalloc(sizeof(struct channel), GFP_KERNEL);
        if (!pch)
                return -ENOMEM;
+
+       pn = ppp_pernet(current->nsproxy->net_ns);
+
        pch->ppp = NULL;
        pch->chan = chan;
        chan->ppp = pch;
@@ -2007,11 +2099,11 @@ ppp_register_channel(struct ppp_channel 
        init_rwsem(&pch->chan_sem);
        spin_lock_init(&pch->downl);
        rwlock_init(&pch->upl);
-       spin_lock_bh(&all_channels_lock);
-       pch->file.index = ++last_channel_index;
-       list_add(&pch->list, &new_channels);
+       spin_lock_bh(&pn->all_channels_lock);
+       pch->file.index = ++pn->last_channel_index;
+       list_add(&pch->list, &pn->new_channels);
        atomic_inc(&channel_count);
-       spin_unlock_bh(&all_channels_lock);
+       spin_unlock_bh(&pn->all_channels_lock);
        return 0;
 }
 
@@ -2052,11 +2144,17 @@ void
 ppp_unregister_channel(struct ppp_channel *chan)
 {
        struct channel *pch = chan->ppp;
+       struct ppp_net *pn;
 
        if (!pch)
                return;         /* should never happen */
        chan->ppp = NULL;
 
+       if (pch->ppp->ppp_net)
+               pn = ppp_pernet(pch->ppp->ppp_net);
+       else
+               pn = ppp_pernet(current->nsproxy->net_ns);
+
        /*
         * This ensures that we have returned from any calls into the
         * the channel's start_xmit or ioctl routine before we proceed.
@@ -2067,9 +2165,9 @@ ppp_unregister_channel(struct ppp_channe
        spin_unlock_bh(&pch->downl);
        up_write(&pch->chan_sem);
        ppp_disconnect_channel(pch);
-       spin_lock_bh(&all_channels_lock);
+       spin_lock_bh(&pn->all_channels_lock);
        list_del(&pch->list);
-       spin_unlock_bh(&all_channels_lock);
+       spin_unlock_bh(&pn->all_channels_lock);
        pch->file.dead = 1;
        wake_up_interruptible(&pch->file.rwait);
        if (atomic_dec_and_test(&pch->file.refcnt))
@@ -2394,10 +2492,11 @@ ppp_get_stats(struct ppp *ppp, struct pp
  * unit == -1 means allocate a new number.
  */
 static struct ppp *
-ppp_create_interface(int unit, int *retp)
+ppp_create_interface(struct net *net, int unit, int *retp)
 {
        struct ppp *ppp;
-       struct net_device *dev = NULL;
+       struct net_device *dev;
+       struct ppp_net *pn;
        int ret = -ENOMEM;
        int i;
 
@@ -2408,6 +2507,7 @@ ppp_create_interface(int unit, int *retp
        ppp = netdev_priv(dev);
        ppp->dev = dev;
        ppp->mru = PPP_MRU;
+       ppp->ppp_net = net;
        init_ppp_file(&ppp->file, INTERFACE);
        ppp->file.hdrlen = PPP_HDRLEN - 2;      /* don't count proto bytes */
        for (i = 0; i < NUM_NP; ++i)
@@ -2421,19 +2521,21 @@ ppp_create_interface(int unit, int *retp
 #endif /* CONFIG_PPP_MULTILINK */
 
        ret = -EEXIST;
-       mutex_lock(&all_ppp_mutex);
+
+       pn = ppp_pernet(net);
+       mutex_lock(&pn->all_ppp_mutex);
 
        if (unit < 0) {
-               unit = unit_get(&ppp_units_idr, ppp);
+               unit = unit_get(net, ppp);
                if (unit < 0) {
                        *retp = unit;
                        goto out2;
                }
        } else {
-               if (unit_find(&ppp_units_idr, unit))
+               if (unit_find(net, unit))
                        goto out2; /* unit already exists */
                else {
-                       /* darn, someone is cheating us? */
+                       /* darn, someone is cheatting us? */
                        *retp = -EINVAL;
                        goto out2;
                }
@@ -2445,20 +2547,20 @@ ppp_create_interface(int unit, int *retp
 
        ret = register_netdev(dev);
        if (ret != 0) {
-               unit_put(&ppp_units_idr, unit);
+               unit_put(net, unit);
                printk(KERN_ERR "PPP: couldn't register device %s (%d)\n",
                       dev->name, ret);
                goto out2;
        }
 
        atomic_inc(&ppp_unit_count);
-       mutex_unlock(&all_ppp_mutex);
+       mutex_unlock(&pn->all_ppp_mutex);
 
        *retp = 0;
        return ppp;
 
 out2:
-       mutex_unlock(&all_ppp_mutex);
+       mutex_unlock(&pn->all_ppp_mutex);
        free_netdev(dev);
 out1:
        *retp = ret;
@@ -2484,7 +2586,9 @@ init_ppp_file(struct ppp_file *pf, int k
  */
 static void ppp_shutdown_interface(struct ppp *ppp)
 {
-       mutex_lock(&all_ppp_mutex);
+       struct ppp_net *pn = ppp_pernet(ppp->ppp_net);
+
+       mutex_lock(&pn->all_ppp_mutex);
        /* This will call dev_close() for us. */
        ppp_lock(ppp);
        if (!ppp->closing) {
@@ -2494,11 +2598,11 @@ static void ppp_shutdown_interface(struc
        } else
                ppp_unlock(ppp);
 
-       unit_put(&ppp_units_idr, ppp->file.index);
+       unit_put(ppp->ppp_net, ppp->file.index);
        ppp->file.dead = 1;
        ppp->owner = NULL;
        wake_up_interruptible(&ppp->file.rwait);
-       mutex_unlock(&all_ppp_mutex);
+       mutex_unlock(&pn->all_ppp_mutex);
 }
 
 /*
@@ -2542,16 +2646,6 @@ static void ppp_destroy_interface(struct
 }
 
 /*
- * Locate an existing ppp unit.
- * The caller should have locked the all_ppp_mutex.
- */
-static struct ppp *
-ppp_find_unit(int unit)
-{
-       return unit_find(&ppp_units_idr, unit);
-}
-
-/*
  * Locate an existing ppp channel.
  * The caller should have locked the all_channels_lock.
  * First we look in the new_channels list, then in the
@@ -2560,20 +2654,25 @@ ppp_find_unit(int unit)
  * when we have a lot of channels in use.
  */
 static struct channel *
-ppp_find_channel(int unit)
+ppp_find_channel(struct net *net, int unit)
 {
        struct channel *pch;
+       struct ppp_net *pn;
+
+       pn = ppp_pernet(net);
 
-       list_for_each_entry(pch, &new_channels, list) {
+       list_for_each_entry(pch, &pn->new_channels, list) {
                if (pch->file.index == unit) {
-                       list_move(&pch->list, &all_channels);
+                       list_move(&pch->list, &pn->all_channels);
                        return pch;
                }
        }
-       list_for_each_entry(pch, &all_channels, list) {
+
+       list_for_each_entry(pch, &pn->all_channels, list) {
                if (pch->file.index == unit)
                        return pch;
        }
+
        return NULL;
 }
 
@@ -2584,11 +2683,14 @@ static int
 ppp_connect_channel(struct channel *pch, int unit)
 {
        struct ppp *ppp;
+       struct ppp_net *pn;
        int ret = -ENXIO;
        int hdrlen;
 
-       mutex_lock(&all_ppp_mutex);
-       ppp = ppp_find_unit(unit);
+       pn = ppp_pernet(current->nsproxy->net_ns);
+
+       mutex_lock(&pn->all_ppp_mutex);
+       ppp = unit_find(current->nsproxy->net_ns, unit);
        if (!ppp)
                goto out;
        write_lock_bh(&pch->upl);
@@ -2612,7 +2714,7 @@ ppp_connect_channel(struct channel *pch,
  outl:
        write_unlock_bh(&pch->upl);
  out:
-       mutex_unlock(&all_ppp_mutex);
+       mutex_unlock(&pn->all_ppp_mutex);
        return ret;
 }
 
@@ -2669,7 +2771,7 @@ static void __exit ppp_cleanup(void)
        unregister_chrdev(PPP_MAJOR, "ppp");
        device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
        class_destroy(ppp_class);
-       idr_destroy(&ppp_units_idr);
+       unregister_pernet_gen_device(ppp_net_id, &ppp_net_ops);
 }
 
 /*
@@ -2678,9 +2780,14 @@ static void __exit ppp_cleanup(void)
  */
 
 /* get new free unit number and associate pointer with it */
-static int unit_get(struct idr *p, void *ptr)
+static int unit_get(struct net *net, void *ptr)
 {
        int unit, err;
+       struct ppp_net *pn;
+       struct idr *p;
+
+       pn = ppp_pernet(net);
+       p = &pn->units_idr;
 
 again:
        if (idr_pre_get(p, GFP_KERNEL) == 0) {
@@ -2696,14 +2803,26 @@ again:
 }
 
 /* put unit number back to a pool */
-static void unit_put(struct idr *p, int n)
+static void unit_put(struct net *net, int n)
 {
+       struct ppp_net *pn;
+       struct idr *p;
+
+       pn = ppp_pernet(net);
+       p = &pn->units_idr;
+
        idr_remove(p, n);
 }
 
 /* get pointer associated with the number */
-static void *unit_find(struct idr *p, int n)
+static void *unit_find(struct net *net, int n)
 {
+       struct ppp_net *pn;
+       struct idr *p;
+
+       pn = ppp_pernet(net);
+       p = &pn->units_idr;
+
        return idr_find(p, n);
 }
 

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