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Michal Kubecek says:

====================
tun: debug messages cleanup

While testing ethtool output for "strange" devices, I noticed confusing and
obviously incorrect message level information for a tun device and sent
a quick fix. The result of the upstream discussion was that tun driver
would rather deserve a more complex cleanup of the way it handles debug
messages.

The main problem is that all debugging statements and setting of message
level are controlled by TUN_DEBUG macro which is only defined if one edits
the source and rebuilds the module, otherwise all DBG1() and tun_debug()
statements do nothing.

This series drops the TUN_DEBUG switch and replaces custom tun_debug()
macro with standard netif_info() so that message level (mask) set and
displayed using ethtool works as expected. Some debugging messages are
dropped as they only notify about entering a function which can be done
easily using ftrace or kprobe.

Patch 1 is a trivial fix for compilation warning with W=1.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Mar 6, 2020
2 parents 9dd620a + 5af0907 commit 425c075
Showing 1 changed file with 27 additions and 78 deletions.
105 changes: 27 additions & 78 deletions drivers/net/tun.c
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Original file line number Diff line number Diff line change
Expand Up @@ -75,35 +75,6 @@
static void tun_default_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *cmd);

/* Uncomment to enable debugging */
/* #define TUN_DEBUG 1 */

#ifdef TUN_DEBUG
static int debug;

#define tun_debug(level, tun, fmt, args...) \
do { \
if (tun->debug) \
netdev_printk(level, tun->dev, fmt, ##args); \
} while (0)
#define DBG1(level, fmt, args...) \
do { \
if (debug == 2) \
printk(level fmt, ##args); \
} while (0)
#else
#define tun_debug(level, tun, fmt, args...) \
do { \
if (0) \
netdev_printk(level, tun->dev, fmt, ##args); \
} while (0)
#define DBG1(level, fmt, args...) \
do { \
if (0) \
printk(level fmt, ##args); \
} while (0)
#endif

#define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)

/* TUN device flags */
Expand Down Expand Up @@ -225,9 +196,7 @@ struct tun_struct {
struct sock_fprog fprog;
/* protected by rtnl lock */
bool filter_attached;
#ifdef TUN_DEBUG
int debug;
#endif
u32 msg_enable;
spinlock_t lock;
struct hlist_head flows[TUN_NUM_FLOW_ENTRIES];
struct timer_list flow_gc_timer;
Expand Down Expand Up @@ -423,8 +392,9 @@ static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,
struct tun_flow_entry *e = kmalloc(sizeof(*e), GFP_ATOMIC);

if (e) {
tun_debug(KERN_INFO, tun, "create flow: hash %u index %u\n",
rxhash, queue_index);
netif_info(tun, tx_queued, tun->dev,
"create flow: hash %u index %u\n",
rxhash, queue_index);
e->updated = jiffies;
e->rxhash = rxhash;
e->rps_rxhash = 0;
Expand All @@ -438,8 +408,8 @@ static struct tun_flow_entry *tun_flow_create(struct tun_struct *tun,

static void tun_flow_delete(struct tun_struct *tun, struct tun_flow_entry *e)
{
tun_debug(KERN_INFO, tun, "delete flow: hash %u index %u\n",
e->rxhash, e->queue_index);
netif_info(tun, tx_queued, tun->dev, "delete flow: hash %u index %u\n",
e->rxhash, e->queue_index);
hlist_del_rcu(&e->hash_link);
kfree_rcu(e, rcu);
--tun->flow_count;
Expand Down Expand Up @@ -485,8 +455,6 @@ static void tun_flow_cleanup(struct timer_list *t)
unsigned long count = 0;
int i;

tun_debug(KERN_INFO, tun, "tun_flow_cleanup\n");

spin_lock(&tun->lock);
for (i = 0; i < TUN_NUM_FLOW_ENTRIES; i++) {
struct tun_flow_entry *e;
Expand Down Expand Up @@ -546,8 +514,7 @@ static void tun_flow_update(struct tun_struct *tun, u32 rxhash,
rcu_read_unlock();
}

/**
* Save the hash received in the stack receive path and update the
/* Save the hash received in the stack receive path and update the
* flow_hash table accordingly.
*/
static inline void tun_flow_save_rps_rxhash(struct tun_flow_entry *e, u32 hash)
Expand Down Expand Up @@ -1076,7 +1043,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
if (!rcu_dereference(tun->steering_prog))
tun_automq_xmit(tun, skb);

tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
netif_info(tun, tx_queued, tun->dev, "%s %d\n", __func__, skb->len);

/* Drop if the filter does not like it.
* This is a noop if the filter is disabled.
Expand Down Expand Up @@ -1433,8 +1400,6 @@ static __poll_t tun_chr_poll(struct file *file, poll_table *wait)

sk = tfile->socket.sk;

tun_debug(KERN_INFO, tun, "tun_chr_poll\n");

poll_wait(file, sk_sleep(sk), wait);

if (!ptr_ring_empty(&tfile->tx_ring))
Expand Down Expand Up @@ -2205,8 +2170,6 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
ssize_t ret;
int err;

tun_debug(KERN_INFO, tun, "tun_do_read\n");

if (!iov_iter_count(to)) {
tun_ptr_free(ptr);
return 0;
Expand Down Expand Up @@ -2851,8 +2814,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)

netif_carrier_on(tun->dev);

tun_debug(KERN_INFO, tun, "tun_set_iff\n");

/* Make sure persistent devices do not get stuck in
* xoff state.
*/
Expand Down Expand Up @@ -2883,8 +2844,6 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)

static void tun_get_iff(struct tun_struct *tun, struct ifreq *ifr)
{
tun_debug(KERN_INFO, tun, "tun_get_iff\n");

strcpy(ifr->ifr_name, tun->dev->name);

ifr->ifr_flags = tun_flags(tun);
Expand Down Expand Up @@ -3108,7 +3067,7 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
if (!tun)
goto unlock;

tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %u\n", cmd);
netif_info(tun, drv, tun->dev, "tun_chr_ioctl cmd %u\n", cmd);

net = dev_net(tun->dev);
ret = 0;
Expand All @@ -3129,8 +3088,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
/* Disable/Enable checksum */

/* [unimplemented] */
tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
arg ? "disabled" : "enabled");
netif_info(tun, drv, tun->dev, "ignored: set checksum %s\n",
arg ? "disabled" : "enabled");
break;

case TUNSETPERSIST:
Expand All @@ -3148,8 +3107,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
do_notify = true;
}

tun_debug(KERN_INFO, tun, "persist %s\n",
arg ? "enabled" : "disabled");
netif_info(tun, drv, tun->dev, "persist %s\n",
arg ? "enabled" : "disabled");
break;

case TUNSETOWNER:
Expand All @@ -3161,8 +3120,8 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
}
tun->owner = owner;
do_notify = true;
tun_debug(KERN_INFO, tun, "owner set to %u\n",
from_kuid(&init_user_ns, tun->owner));
netif_info(tun, drv, tun->dev, "owner set to %u\n",
from_kuid(&init_user_ns, tun->owner));
break;

case TUNSETGROUP:
Expand All @@ -3174,29 +3133,28 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
}
tun->group = group;
do_notify = true;
tun_debug(KERN_INFO, tun, "group set to %u\n",
from_kgid(&init_user_ns, tun->group));
netif_info(tun, drv, tun->dev, "group set to %u\n",
from_kgid(&init_user_ns, tun->group));
break;

case TUNSETLINK:
/* Only allow setting the type when the interface is down */
if (tun->dev->flags & IFF_UP) {
tun_debug(KERN_INFO, tun,
"Linktype set failed because interface is up\n");
netif_info(tun, drv, tun->dev,
"Linktype set failed because interface is up\n");
ret = -EBUSY;
} else {
tun->dev->type = (int) arg;
tun_debug(KERN_INFO, tun, "linktype set to %d\n",
tun->dev->type);
netif_info(tun, drv, tun->dev, "linktype set to %d\n",
tun->dev->type);
ret = 0;
}
break;

#ifdef TUN_DEBUG
case TUNSETDEBUG:
tun->debug = arg;
tun->msg_enable = (u32)arg;
break;
#endif

case TUNSETOFFLOAD:
ret = set_offload(tun, arg);
break;
Expand All @@ -3219,9 +3177,6 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,

case SIOCSIFHWADDR:
/* Set hw address */
tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
ifr.ifr_hwaddr.sa_data);

ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr, NULL);
break;

Expand Down Expand Up @@ -3416,8 +3371,6 @@ static int tun_chr_open(struct inode *inode, struct file * file)
struct net *net = current->nsproxy->net_ns;
struct tun_file *tfile;

DBG1(KERN_INFO, "tunX: tun_chr_open\n");

tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
&tun_proto, 0);
if (!tfile)
Expand Down Expand Up @@ -3557,20 +3510,16 @@ static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info

static u32 tun_get_msglevel(struct net_device *dev)
{
#ifdef TUN_DEBUG
struct tun_struct *tun = netdev_priv(dev);
return tun->debug;
#else
return -EOPNOTSUPP;
#endif

return tun->msg_enable;
}

static void tun_set_msglevel(struct net_device *dev, u32 value)
{
#ifdef TUN_DEBUG
struct tun_struct *tun = netdev_priv(dev);
tun->debug = value;
#endif

tun->msg_enable = value;
}

static int tun_get_coalesce(struct net_device *dev,
Expand Down

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