[PATCH 2/3] netconsole: make loglevel configurable per target
From: Bruno PrÃmont
Date: Tue Dec 23 2014 - 16:27:50 EST
Switch to registering a new console for each target so that loglevel
based message filtering can be set individually for each target.
This adds a new loglevel= option to netconsole module parameter and also
add a configfs file to configure the loglevel.
The loglevel conf be adjusted at any time for synamic netconsole
consoles.
Signed-off-by: Bruno PrÃmont <bonbons@xxxxxxxxxxxxxxxxx>
---
Note: only configuration via configfs has been runtime-tested.
Documentation/networking/netconsole.txt | 11 ++-
drivers/net/netconsole.c | 114 +++++++++++++++++++++++---------
2 files changed, 94 insertions(+), 31 deletions(-)
diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt
index a5d574a..c1df516 100644
--- a/Documentation/networking/netconsole.txt
+++ b/Documentation/networking/netconsole.txt
@@ -24,7 +24,7 @@ Sender and receiver configuration:
It takes a string configuration parameter "netconsole" in the
following format:
- netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
+ netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr][,loglevel=level]
where
src-port source for UDP packets (defaults to 6665)
@@ -33,6 +33,9 @@ following format:
tgt-port port for logging agent (6666)
tgt-ip IP address for logging agent
tgt-macaddr ethernet MAC address for logging agent (broadcast)
+ level limit messages printed to those whose loglevel is
+ smaller that value, range is 1 to 8
+ If missing, loglevel limit as set via syslog(1) applies
Examples:
@@ -114,11 +117,16 @@ The interface exposes these parameters of a netconsole target to userspace:
remote_ip Remote agent's IP address (read-write)
local_mac Local interface's MAC address (read-only)
remote_mac Remote agent's MAC address (read-write)
+ loglevel Console loglevel filter (read-write)
The "enabled" attribute is also used to control whether the parameters of
a target can be updated or not -- you can modify the parameters of only
disabled targets (i.e. if "enabled" is 0).
+The "loglevel" parameter can be set at any time. When set to "0" it will
+read back as empty string and global loglevel filter applies. Otherwise
+specified loglevel filter applies.
+
To update a target's parameters:
cat enabled # check if enabled is 1
@@ -164,6 +172,7 @@ priority messages to the console. You can change this at runtime using:
dmesg -n 8
+or by specifying netconsole loglevel parameter
or by specifying "debug" on the kernel command line at boot, to send
all kernel messages to the console. A specific value for this parameter
can also be set using the "loglevel" kernel boot option. See the
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index ba2f5e7..a96cd8e 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -103,10 +103,12 @@ struct netconsole_target {
#ifdef CONFIG_NETCONSOLE_DYNAMIC
struct config_item item;
#endif
+ struct console console;
int enabled;
struct mutex mutex;
struct netpoll np;
};
+static void write_msg(struct console *con, const char *msg, unsigned int len);
#ifdef CONFIG_NETCONSOLE_DYNAMIC
@@ -171,6 +173,7 @@ static struct netconsole_target *alloc_param_target(char *target_config)
{
int err = -ENOMEM;
struct netconsole_target *nt;
+ char *loglevel;
/*
* Allocate and initialize with defaults.
@@ -186,8 +189,26 @@ static struct netconsole_target *alloc_param_target(char *target_config)
nt->np.remote_port = 6666;
mutex_init(&nt->mutex);
memset(nt->np.remote_mac, 0xff, ETH_ALEN);
+ snprintf(nt->console.name, sizeof(nt->console.name), "netcon");
+ /* Dump existing printks when we register */
+ nt->console.flags = CON_ENABLED | CON_PRINTBUFFER;
+ nt->console.write = write_msg;
/* Parse parameters and setup netpoll */
+ loglevel = strstr(target_config, ",loglevel=");
+ if (loglevel) {
+ int level;
+ err = kstrtoint(loglevel+10, 10, &level);
+ if (err < 0)
+ goto fail;
+ if (level < 1 || level > 8) {
+ err = -EINVAL;
+ goto fail;
+ }
+ nt->console.loglevel = level;
+ nt->console.flags |= CON_LOGLEVEL;
+ *loglevel = '\0';
+ }
err = netpoll_parse_options(&nt->np, target_config);
if (err)
goto fail;
@@ -228,6 +249,7 @@ static void free_param_target(struct netconsole_target *nt)
* | remote_ip
* | local_mac
* | remote_mac
+ * | loglevel
* |
* <target>/...
*/
@@ -301,6 +323,14 @@ static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
}
+static ssize_t show_loglevel(struct netconsole_target *nt, char *buf)
+{
+ if (nt->console.flags & CON_LOGLEVEL)
+ return snprintf(buf, PAGE_SIZE, "%u\n", nt->console.loglevel);
+ else
+ return snprintf(buf, PAGE_SIZE, "\n");
+}
+
/*
* This one is special -- targets created through the configfs interface
* are not enabled (and the corresponding netpoll activated) by default.
@@ -338,6 +368,8 @@ static ssize_t store_enabled(struct netconsole_target *nt,
if (err)
return err;
+ nt->enabled = 1;
+ register_console(&nt->console);
pr_info("netconsole: network logging started\n");
} else { /* 0 */
/* We need to disable the netconsole before cleaning it up
@@ -347,11 +379,11 @@ static ssize_t store_enabled(struct netconsole_target *nt,
spin_lock_irqsave(&target_list_lock, flags);
nt->enabled = 0;
spin_unlock_irqrestore(&target_list_lock, flags);
+ unregister_console(&nt->console);
netpoll_cleanup(&nt->np);
+ nt->console.flags = nt->console.flags & ~CON_PRINTBUFFER;
}
- nt->enabled = enabled;
-
return strnlen(buf, count);
}
@@ -494,6 +526,27 @@ static ssize_t store_remote_mac(struct netconsole_target *nt,
return strnlen(buf, count);
}
+static ssize_t store_loglevel(struct netconsole_target *nt,
+ const char *buf,
+ size_t count)
+{
+ int rv, level;
+
+ rv = kstrtoint(buf, 10, &level);
+ if (rv < 0)
+ return rv;
+ if (level < 0 || level > 8)
+ return -EINVAL;
+
+ if (level > 0) {
+ nt->console.loglevel = level;
+ nt->console.flags |= CON_LOGLEVEL;
+ } else
+ nt->console.flags &= ~CON_LOGLEVEL;
+
+ return strnlen(buf, count);
+}
+
/*
* Attribute definitions for netconsole_target.
*/
@@ -514,6 +567,7 @@ NETCONSOLE_TARGET_ATTR_RW(local_ip);
NETCONSOLE_TARGET_ATTR_RW(remote_ip);
NETCONSOLE_TARGET_ATTR_RO(local_mac);
NETCONSOLE_TARGET_ATTR_RW(remote_mac);
+NETCONSOLE_TARGET_ATTR_RW(loglevel);
static struct configfs_attribute *netconsole_target_attrs[] = {
&netconsole_target_enabled.attr,
@@ -524,6 +578,7 @@ static struct configfs_attribute *netconsole_target_attrs[] = {
&netconsole_target_remote_ip.attr,
&netconsole_target_local_mac.attr,
&netconsole_target_remote_mac.attr,
+ &netconsole_target_loglevel.attr,
NULL,
};
@@ -605,6 +660,10 @@ static struct config_item *make_netconsole_target(struct config_group *group,
nt->np.remote_port = 6666;
mutex_init(&nt->mutex);
memset(nt->np.remote_mac, 0xff, ETH_ALEN);
+ snprintf(nt->console.name, sizeof(nt->console.name), "netcon-%s", name);
+ nt->console.flags = CON_ENABLED;
+ nt->console.write = write_msg;
+ nt->console.loglevel = 0;
/* Initialize the config_item member */
config_item_init_type_name(&nt->item, name, &netconsole_target_type);
@@ -626,6 +685,7 @@ static void drop_netconsole_target(struct config_group *group,
spin_lock_irqsave(&target_list_lock, flags);
list_del(&nt->list);
spin_unlock_irqrestore(&target_list_lock, flags);
+ unregister_console(&nt->console);
/*
* The target may have never been enabled, or was manually disabled
@@ -732,7 +792,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
{
int frag, left;
unsigned long flags;
- struct netconsole_target *nt;
+ struct netconsole_target *nt = container_of(con, struct netconsole_target, console);
const char *tmp;
if (oops_only && !oops_in_progress)
@@ -742,34 +802,26 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
return;
spin_lock_irqsave(&target_list_lock, flags);
- list_for_each_entry(nt, &target_list, list) {
- netconsole_target_get(nt);
- if (nt->enabled && netif_running(nt->np.dev)) {
- /*
- * We nest this inside the for-each-target loop above
- * so that we're able to get as much logging out to
- * at least one target if we die inside here, instead
- * of unnecessarily keeping all targets in lock-step.
- */
- tmp = msg;
- for (left = len; left;) {
- frag = min(left, MAX_PRINT_CHUNK);
- netpoll_send_udp(&nt->np, tmp, frag);
- tmp += frag;
- left -= frag;
- }
+ netconsole_target_get(nt);
+ if (nt->enabled && netif_running(nt->np.dev)) {
+ /*
+ * We nest this inside the for-each-target loop above
+ * so that we're able to get as much logging out to
+ * at least one target if we die inside here, instead
+ * of unnecessarily keeping all targets in lock-step.
+ */
+ tmp = msg;
+ for (left = len; left;) {
+ frag = min(left, MAX_PRINT_CHUNK);
+ netpoll_send_udp(&nt->np, tmp, frag);
+ tmp += frag;
+ left -= frag;
}
- netconsole_target_put(nt);
}
+ netconsole_target_put(nt);
spin_unlock_irqrestore(&target_list_lock, flags);
}
-static struct console netconsole = {
- .name = "netcon",
- .flags = CON_ENABLED,
- .write = write_msg,
-};
-
static int __init init_netconsole(void)
{
int err;
@@ -785,8 +837,6 @@ static int __init init_netconsole(void)
err = PTR_ERR(nt);
goto fail;
}
- /* Dump existing printks when we register */
- netconsole.flags |= CON_PRINTBUFFER;
spin_lock_irqsave(&target_list_lock, flags);
list_add(&nt->list, &target_list);
@@ -802,7 +852,9 @@ static int __init init_netconsole(void)
if (err)
goto undonotifier;
- register_console(&netconsole);
+ list_for_each_entry_safe(nt, tmp, &target_list, list) {
+ register_console(&nt->console);
+ }
pr_info("network logging started\n");
return err;
@@ -830,7 +882,9 @@ static void __exit cleanup_netconsole(void)
{
struct netconsole_target *nt, *tmp;
- unregister_console(&netconsole);
+ list_for_each_entry_safe(nt, tmp, &target_list, list) {
+ unregister_console(&nt->console);
+ }
dynamic_netconsole_exit();
unregister_netdevice_notifier(&netconsole_netdev_notifier);
--
2.0.4
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