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Subject[PATCH v2 09/23] netconsole: Add pointer to netpoll_targets
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For each netconsole_target, we'd like to get back at the parenting
netpoll_targets structure so that we can access the locking and list
fields. Add a pointer that points to the netpoll_targets structure. We
don't have to maintain reference counting because a netpoll_targets will
always out-live their children netconsole_target structures.

Signed-off-by: Mike Waychison <mikew@google.com>
---
drivers/net/netconsole.c | 71 +++++++++++++++++++++++++++++-----------------
1 files changed, 45 insertions(+), 26 deletions(-)
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 54d124c..ec8bda2 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -107,6 +107,7 @@ static DEFINE_NETPOLL_TARGETS(targets);
* remote_mac (read-write)
*/
struct netconsole_target {
+ struct netpoll_targets *nts;
struct list_head list;
#ifdef CONFIG_NETCONSOLE_DYNAMIC
struct config_item item;
@@ -122,21 +123,25 @@ static void netconsole_target_put(struct netconsole_target *nt);
static void deferred_netpoll_cleanup(struct work_struct *work)
{
struct netconsole_target *nt;
+ struct netpoll_targets *nts;
unsigned long flags;

nt = container_of(work, struct netconsole_target, cleanup_work);
+ nts = nt->nts;
+
netpoll_cleanup(&nt->np);

- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
BUG_ON(nt->np_state != NETPOLL_CLEANING);
nt->np_state = NETPOLL_DISABLED;
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);

netconsole_target_put(nt);
}

/* Allocate new target (from boot/module param) and setup netpoll for it */
-static struct netconsole_target *alloc_param_target(char *target_config)
+static struct netconsole_target *alloc_param_target(struct netpoll_targets *nts,
+ char *target_config)
{
int err = -ENOMEM;
struct netconsole_target *nt;
@@ -151,6 +156,7 @@ static struct netconsole_target *alloc_param_target(char *target_config)
goto fail;
}

+ nt->nts = nts;
nt->np.name = "netconsole";
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
@@ -308,6 +314,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
const char *buf,
size_t count)
{
+ struct netpoll_targets *nts = nt->nts;
unsigned long flags;
int err;
long enabled;
@@ -317,7 +324,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
return enabled;

if (enabled) { /* 1 */
- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
if (nt->np_state != NETPOLL_DISABLED)
goto busy;
else {
@@ -329,7 +336,7 @@ static ssize_t store_enabled(struct netconsole_target *nt,
* because there is a reference implicitly held by the
* caller of the store operation.
*/
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);
}

/*
@@ -339,34 +346,34 @@ static ssize_t store_enabled(struct netconsole_target *nt,
netpoll_print_options(&nt->np);

err = netpoll_setup(&nt->np);
- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
if (err)
nt->np_state = NETPOLL_DISABLED;
else
nt->np_state = NETPOLL_ENABLED;
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);
if (err)
return err;

printk(KERN_INFO "netconsole: network logging started\n");
} else { /* 0 */
- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
if (nt->np_state == NETPOLL_ENABLED)
nt->np_state = NETPOLL_CLEANING;
else if (nt->np_state != NETPOLL_DISABLED)
goto busy;
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);

netpoll_cleanup(&nt->np);

- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
nt->np_state = NETPOLL_DISABLED;
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);
}

return strnlen(buf, count);
busy:
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);
return -EBUSY;
}

@@ -481,29 +488,31 @@ static ssize_t store_locked_##_name(struct netconsole_target *nt, \
const char *buf, \
size_t count) \
{ \
+ struct netpoll_targets *nts = nt->nts; \
unsigned long flags; \
ssize_t ret; \
- spin_lock_irqsave(&targets.lock, flags); \
+ spin_lock_irqsave(&nts->lock, flags); \
if (nt->np_state != NETPOLL_DISABLED) { \
printk(KERN_ERR "netconsole: target (%s) is enabled, " \
"disable to update parameters\n", \
config_item_name(&nt->item)); \
- spin_unlock_irqrestore(&targets.lock, flags); \
+ spin_unlock_irqrestore(&nts->lock, flags); \
return -EBUSY; \
} \
ret = store_##_name(nt, buf, count); \
- spin_unlock_irqrestore(&targets.lock, flags); \
+ spin_unlock_irqrestore(&nts->lock, flags); \
return ret; \
}

#define NETCONSOLE_WRAP_ATTR_SHOW(_name) \
static ssize_t show_locked_##_name(struct netconsole_target *nt, char *buf) \
{ \
+ struct netpoll_targets *nts = nt->nts; \
unsigned long flags; \
ssize_t ret; \
- spin_lock_irqsave(&targets.lock, flags); \
+ spin_lock_irqsave(&nts->lock, flags); \
ret = show_##_name(nt, buf); \
- spin_unlock_irqrestore(&targets.lock, flags); \
+ spin_unlock_irqrestore(&nts->lock, flags); \
return ret; \
}

@@ -589,6 +598,13 @@ static struct config_item_type netconsole_target_type = {
.ct_owner = THIS_MODULE,
};

+static struct netpoll_targets *group_to_targets(struct config_group *group)
+{
+ struct configfs_subsystem *subsys;
+ subsys = container_of(group, struct configfs_subsystem, su_group);
+ return container_of(subsys, struct netpoll_targets, configfs_subsys);
+}
+
/*
* Group operations and type for netconsole_subsys.
*/
@@ -596,8 +612,9 @@ static struct config_item_type netconsole_target_type = {
static struct config_item *make_netconsole_target(struct config_group *group,
const char *name)
{
- unsigned long flags;
+ struct netpoll_targets *nts = group_to_targets(group);
struct netconsole_target *nt;
+ unsigned long flags;

/*
* Allocate and initialize with defaults.
@@ -609,6 +626,7 @@ static struct config_item *make_netconsole_target(struct config_group *group,
return ERR_PTR(-ENOMEM);
}

+ nt->nts = nts;
nt->np.name = "netconsole";
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
@@ -620,9 +638,9 @@ static struct config_item *make_netconsole_target(struct config_group *group,
config_item_init_type_name(&nt->item, name, &netconsole_target_type);

/* Adding, but it is disabled */
- spin_lock_irqsave(&targets.lock, flags);
- list_add(&nt->list, &targets.list);
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
+ list_add(&nt->list, &nts->list);
+ spin_unlock_irqrestore(&nts->lock, flags);

return &nt->item;
}
@@ -630,12 +648,13 @@ static struct config_item *make_netconsole_target(struct config_group *group,
static void drop_netconsole_target(struct config_group *group,
struct config_item *item)
{
- unsigned long flags;
+ struct netpoll_targets *nts = group_to_targets(group);
struct netconsole_target *nt = to_target(item);
+ unsigned long flags;

- spin_lock_irqsave(&targets.lock, flags);
+ spin_lock_irqsave(&nts->lock, flags);
list_del(&nt->list);
- spin_unlock_irqrestore(&targets.lock, flags);
+ spin_unlock_irqrestore(&nts->lock, flags);

/*
* The target may have never been enabled, or was manually disabled
@@ -723,7 +742,7 @@ static void netconsole_target_put(struct netconsole_target *nt)

/*
* Call netpoll_cleanup on this target asynchronously.
- * targets.lock is required.
+ * nts->lock is required.
*/
static void defer_netpoll_cleanup(struct netconsole_target *nt)
{
@@ -827,7 +846,7 @@ static int __init register_netpoll_targets(const char *subsys_name,

if (strnlen(input, MAX_PARAM_LENGTH)) {
while ((target_config = strsep(&input, ";"))) {
- nt = alloc_param_target(target_config);
+ nt = alloc_param_target(nts, target_config);
if (IS_ERR(nt)) {
err = PTR_ERR(nt);
goto fail;


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