[PATCH 07/14] w1: process w1 netlink commands in w1_process thread

David Fries
2013-12-29T06:54:04Z

Netlink is a socket interface and is expected to be asynchronous.
Clients can now make w1 requests without blocking by making use of the
w1_master thread to process netlink commands which was previously only
used for doing an automatic bus search.

Signed-off-by: David Fries <David@Fries.net>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
---
drivers/w1/w1.c | 180 +++++++++++++++++++++++++++++++++--------------
drivers/w1/w1.h | 32 ++++++++-
drivers/w1/w1_int.c | 17 +++--
drivers/w1/w1_netlink.c | 166 +++++++++++++++++++++++++++++++++----------
4 files changed, 300 insertions(+), 95 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 97b35cb..53846c7 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -79,19 +79,10 @@ static void w1_slave_release(struct device *dev)
{
struct w1_slave *sl = dev_to_w1_slave(dev);

- dev_dbg(dev, "%s: Releasing %s.\n", __func__, sl->name);
-
- while (atomic_read(&sl->refcnt)) {
- dev_dbg(dev, "Waiting for %s to become free: refcnt=%d.\n",
- sl->name, atomic_read(&sl->refcnt));
- if (msleep_interruptible(1000))
- flush_signals(current);
- }
+ dev_dbg(dev, "%s: Releasing %s [%p]\n", __func__, sl->name, sl);

w1_family_put(sl->family);
sl->master->slave_count--;
-
- complete(&sl->released);
}

static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf)
@@ -277,7 +268,6 @@ static ssize_t w1_master_attribute_store_pullup(struct device *dev,
mutex_lock(&md->mutex);
md->enable_pullup = tmp;
mutex_unlock(&md->mutex);
- wake_up_process(md->thread);

return count;
}
@@ -370,23 +360,20 @@ static ssize_t w1_master_attribute_show_slaves(struct device *dev,
{
struct w1_master *md = dev_to_w1_master(dev);
int c = PAGE_SIZE;
+ struct list_head *ent, *n;
+ struct w1_slave *sl = NULL;

- mutex_lock(&md->mutex);
-
- if (md->slave_count == 0)
- c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");
- else {
- struct list_head *ent, *n;
- struct w1_slave *sl;
+ mutex_lock(&md->list_mutex);

- list_for_each_safe(ent, n, &md->slist) {
- sl = list_entry(ent, struct w1_slave, w1_slave_entry);
+ list_for_each_safe(ent, n, &md->slist) {
+ sl = list_entry(ent, struct w1_slave, w1_slave_entry);

- c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
- }
+ c -= snprintf(buf + PAGE_SIZE - c, c, "%s\n", sl->name);
}
+ if (!sl)
+ c -= snprintf(buf + PAGE_SIZE - c, c, "not found.\n");

- mutex_unlock(&md->mutex);
+ mutex_unlock(&md->list_mutex);

return PAGE_SIZE - c;
}
@@ -440,19 +427,22 @@ static int w1_atoreg_num(struct device *dev, const char *buf, size_t count,
}

/* Searches the slaves in the w1_master and returns a pointer or NULL.
- * Note: must hold the mutex
+ * Note: must not hold list_mutex
*/
struct w1_slave *w1_slave_search_device(struct w1_master *dev,
struct w1_reg_num *rn)
{
struct w1_slave *sl;
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
if (sl->reg_num.family == rn->family &&
sl->reg_num.id == rn->id &&
sl->reg_num.crc == rn->crc) {
+ mutex_unlock(&dev->list_mutex);
return sl;
}
}
+ mutex_unlock(&dev->list_mutex);
return NULL;
}

@@ -509,7 +499,10 @@ static ssize_t w1_master_attribute_store_remove(struct device *dev,
mutex_lock(&md->mutex);
sl = w1_slave_search_device(md, &rn);
if (sl) {
- w1_slave_detach(sl);
+ result = w1_slave_detach(sl);
+ /* refcnt 0 means it was detached in the call */
+ if (result == 0)
+ result = count;
} else {
dev_info(dev, "Device %02x-%012llx doesn't exists\n", rn.family,
(unsigned long long)rn.id);
@@ -704,7 +697,9 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
dev_set_uevent_suppress(&sl->dev, false);
kobject_uevent(&sl->dev.kobj, KOBJ_ADD);

+ mutex_lock(&sl->master->list_mutex);
list_add_tail(&sl->w1_slave_entry, &sl->master->slist);
+ mutex_unlock(&sl->master->list_mutex);

return 0;
}
@@ -731,8 +726,8 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)

memset(&msg, 0, sizeof(msg));
memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
- atomic_set(&sl->refcnt, 0);
- init_completion(&sl->released);
+ atomic_set(&sl->refcnt, 1);
+ atomic_inc(&sl->master->refcnt);

/* slave modules need to be loaded in a context with unlocked mutex */
mutex_unlock(&dev->mutex);
@@ -772,23 +767,48 @@ int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
return 0;
}

-void w1_slave_detach(struct w1_slave *sl)
+int w1_unref_slave(struct w1_slave *sl)
{
- struct w1_netlink_msg msg;
-
- dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__, sl->name, sl);
-
- list_del(&sl->w1_slave_entry);
-
- memset(&msg, 0, sizeof(msg));
- memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
- msg.type = W1_SLAVE_REMOVE;
- w1_netlink_send(sl->master, &msg);
-
- device_unregister(&sl->dev);
+ struct w1_master *dev = sl->master;
+ int refcnt;
+ mutex_lock(&dev->list_mutex);
+ refcnt = atomic_sub_return(1, &sl->refcnt);
+ if (refcnt == 0) {
+ struct w1_netlink_msg msg;
+
+ dev_dbg(&sl->dev, "%s: detaching %s [%p].\n", __func__,
+ sl->name, sl);
+
+ list_del(&sl->w1_slave_entry);
+
+ memset(&msg, 0, sizeof(msg));
+ memcpy(msg.id.id, &sl->reg_num, sizeof(msg.id));
+ msg.type = W1_SLAVE_REMOVE;
+ w1_netlink_send(sl->master, &msg);
+
+ device_unregister(&sl->dev);
+ #ifdef DEBUG
+ memset(sl, 0, sizeof(*sl));
+ #endif
+ kfree(sl);
+ }
+ atomic_dec(&dev->refcnt);
+ mutex_unlock(&dev->list_mutex);
+ return refcnt;
+}

- wait_for_completion(&sl->released);
- kfree(sl);
+int w1_slave_detach(struct w1_slave *sl)
+{
+ /* Only detach a slave once as it decreases the refcnt each time. */
+ int destroy_now;
+ mutex_lock(&sl->master->list_mutex);
+ destroy_now = !test_bit(W1_SLAVE_DETACH, &sl->flags);
+ set_bit(W1_SLAVE_DETACH, &sl->flags);
+ mutex_unlock(&sl->master->list_mutex);
+
+ if (destroy_now)
+ destroy_now = !w1_unref_slave(sl);
+ return destroy_now ? 0 : -EBUSY;
}

struct w1_master *w1_search_master_id(u32 id)
@@ -817,7 +837,7 @@ struct w1_slave *w1_search_slave(struct w1_reg_num *id)

mutex_lock(&w1_mlock);
list_for_each_entry(dev, &w1_masters, w1_master_entry) {
- mutex_lock(&dev->mutex);
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
if (sl->reg_num.family == id->family &&
sl->reg_num.id == id->id &&
@@ -828,7 +848,7 @@ struct w1_slave *w1_search_slave(struct w1_reg_num *id)
break;
}
}
- mutex_unlock(&dev->mutex);
+ mutex_unlock(&dev->list_mutex);

if (found)
break;
@@ -848,6 +868,7 @@ void w1_reconnect_slaves(struct w1_family *f, int attach)
dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
"for family %02x.\n", dev->name, f->fid);
mutex_lock(&dev->mutex);
+ mutex_lock(&dev->list_mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
/* If it is a new family, slaves with the default
* family driver and are that family will be
@@ -859,14 +880,19 @@ void w1_reconnect_slaves(struct w1_family *f, int attach)
(!attach && sl->family->fid == f->fid)) {
struct w1_reg_num rn;

+ mutex_unlock(&dev->list_mutex);
memcpy(&rn, &sl->reg_num, sizeof(rn));
- w1_slave_detach(sl);
-
- w1_attach_slave_device(dev, &rn);
+ /* If it was already in use let the automatic
+ * scan pick it up again later.
+ */
+ if (!w1_slave_detach(sl))
+ w1_attach_slave_device(dev, &rn);
+ mutex_lock(&dev->list_mutex);
}
}
dev_dbg(&dev->dev, "Reconnecting slaves in device %s "
"has been finished.\n", dev->name);
+ mutex_unlock(&dev->list_mutex);
mutex_unlock(&dev->mutex);
}
mutex_unlock(&w1_mlock);
@@ -1020,17 +1046,24 @@ void w1_search_process_cb(struct w1_master *dev, u8 search_type,
{
struct w1_slave *sl, *sln;

+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry)
clear_bit(W1_SLAVE_ACTIVE, &sl->flags);
+ mutex_unlock(&dev->list_mutex);

w1_search_devices(dev, search_type, cb);

+ mutex_lock(&dev->list_mutex);
list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
- if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl)
+ if (!test_bit(W1_SLAVE_ACTIVE, &sl->flags) && !--sl->ttl) {
+ mutex_unlock(&dev->list_mutex);
w1_slave_detach(sl);
+ mutex_lock(&dev->list_mutex);
+ }
else if (test_bit(W1_SLAVE_ACTIVE, &sl->flags))
sl->ttl = dev->slave_ttl;
}
+ mutex_unlock(&dev->list_mutex);

if (dev->search_count > 0)
dev->search_count--;
@@ -1041,6 +1074,26 @@ static void w1_search_process(struct w1_master *dev, u8 search_type)
w1_search_process_cb(dev, search_type, w1_slave_found);
}

+int w1_process_callbacks(struct w1_master *dev)
+{
+ int ret = 0;
+ struct w1_async_cmd *async_cmd, *async_n;
+
+ /* The list can be added to in another thread, loop until it is empty */
+ while (!list_empty(&dev->async_list)) {
+ list_for_each_entry_safe(async_cmd, async_n, &dev->async_list,
+ async_entry) {
+ /* drop the lock, if it is a search it can take a long
+ * time */
+ mutex_unlock(&dev->list_mutex);
+ async_cmd->cb(dev, async_cmd);
+ ret = 1;
+ mutex_lock(&dev->list_mutex);
+ }
+ }
+ return ret;
+}
+
int w1_process(void *data)
{
struct w1_master *dev = (struct w1_master *) data;
@@ -1048,23 +1101,46 @@ int w1_process(void *data)
* time can be calculated in jiffies once.
*/
const unsigned long jtime = msecs_to_jiffies(w1_timeout * 1000);
+ /* remainder if it woke up early */
+ unsigned long jremain = 0;

- while (!kthread_should_stop()) {
- if (dev->search_count) {
+ for (;;) {
+
+ if (!jremain && dev->search_count) {
mutex_lock(&dev->mutex);
w1_search_process(dev, W1_SEARCH);
mutex_unlock(&dev->mutex);
}

+ mutex_lock(&dev->list_mutex);
+ /* Note, w1_process_callback drops the lock while processing,
+ * but locks it again before returning.
+ */
+ if (!w1_process_callbacks(dev) && jremain) {
+ /* a wake up is either to stop the thread, process
+ * callbacks, or search, it isn't process callbacks, so
+ * schedule a search.
+ */
+ jremain = 1;
+ }
+
try_to_freeze();
__set_current_state(TASK_INTERRUPTIBLE);

+ /* hold list_mutex until after interruptible to prevent loosing
+ * the wakeup signal when async_cmd is added.
+ */
+ mutex_unlock(&dev->list_mutex);
+
if (kthread_should_stop())
break;

/* Only sleep when the search is active. */
- if (dev->search_count)
- schedule_timeout(jtime);
+ if (dev->search_count) {
+ if (!jremain)
+ jremain = jtime;
+ jremain = schedule_timeout(jremain);
+ }
else
schedule();
}
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 3376bfb..a096ef4 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -58,6 +58,7 @@ struct w1_reg_num
#define W1_RESUME_CMD 0xA5

#define W1_SLAVE_ACTIVE 0
+#define W1_SLAVE_DETACH 1

struct w1_slave
{
@@ -74,7 +75,6 @@ struct w1_slave
struct w1_family *family;
void *family_data;
struct device dev;
- struct completion released;
};

typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
@@ -171,7 +171,14 @@ struct w1_master
struct list_head w1_master_entry;
struct module *owner;
unsigned char name[W1_MAXNAMELEN];
+ /* list_mutex protects just slist and async_list so slaves can be
+ * searched for and async commands added while the master has
+ * w1_master.mutex locked and is operating on the bus.
+ * lock order w1_mlock, w1_master.mutex, w1_master_list_mutex
+ */
+ struct mutex list_mutex;
struct list_head slist;
+ struct list_head async_list;
int max_slave_count, slave_count;
unsigned long attempts;
int slave_ttl;
@@ -205,11 +212,29 @@ struct w1_master
u32 seq;
};

+/**
+ * struct w1_async_cmd - execute callback from the w1_process kthread
+ * @async_entry: link entry
+ * @cb: callback function, must list_del and destroy this list before
+ * returning
+ *
+ * When inserted into the w1_master async_list, w1_process will execute
+ * the callback. Embed this into the structure with the command details.
+ */
+struct w1_async_cmd {
+ struct list_head async_entry;
+ void (*cb)(struct w1_master *dev, struct w1_async_cmd *async_cmd);
+};
+
int w1_create_master_attributes(struct w1_master *);
void w1_destroy_master_attributes(struct w1_master *master);
void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
+/* call w1_unref_slave to release the reference counts w1_search_slave added */
struct w1_slave *w1_search_slave(struct w1_reg_num *id);
+/* decrements the reference on sl->master and sl, and cleans up if zero
+ * returns the reference count after it has been decremented */
+int w1_unref_slave(struct w1_slave *sl);
void w1_slave_found(struct w1_master *dev, u64 rn);
void w1_search_process_cb(struct w1_master *dev, u8 search_type,
w1_slave_found_callback cb);
@@ -224,7 +249,8 @@ struct w1_master *w1_search_master_id(u32 id);
*/
void w1_reconnect_slaves(struct w1_family *f, int attach);
int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
-void w1_slave_detach(struct w1_slave *sl);
+/* 0 success, otherwise EBUSY */
+int w1_slave_detach(struct w1_slave *sl);

u8 w1_triplet(struct w1_master *dev, int bdir);
void w1_write_8(struct w1_master *, u8);
@@ -260,6 +286,8 @@ extern int w1_max_slave_ttl;
extern struct list_head w1_masters;
extern struct mutex w1_mlock;

+/* returns 1 if there were commands to executed 0 otherwise */
+extern int w1_process_callbacks(struct w1_master *dev);
extern int w1_process(void *);

#endif /* __KERNEL__ */
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 423f3c2..66b2caa 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -75,8 +75,10 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
atomic_set(&dev->refcnt, 2);

INIT_LIST_HEAD(&dev->slist);
+ INIT_LIST_HEAD(&dev->async_list);
mutex_init(&dev->mutex);
mutex_init(&dev->bus_mutex);
+ mutex_init(&dev->list_mutex);

memcpy(&dev->dev, device, sizeof(struct device));
dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
@@ -188,17 +190,22 @@ void __w1_remove_master_device(struct w1_master *dev)
struct w1_netlink_msg msg;
struct w1_slave *sl, *sln;

- set_bit(W1_ABORT_SEARCH, &dev->flags);
- kthread_stop(dev->thread);
-
mutex_lock(&w1_mlock);
list_del(&dev->w1_master_entry);
mutex_unlock(&w1_mlock);

+ set_bit(W1_ABORT_SEARCH, &dev->flags);
+ kthread_stop(dev->thread);
+
mutex_lock(&dev->mutex);
- list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry)
+ mutex_lock(&dev->list_mutex);
+ list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
+ mutex_unlock(&dev->list_mutex);
w1_slave_detach(sl);
+ mutex_lock(&dev->list_mutex);
+ }
w1_destroy_master_attributes(dev);
+ mutex_unlock(&dev->list_mutex);
mutex_unlock(&dev->mutex);
atomic_dec(&dev->refcnt);

@@ -208,7 +215,9 @@ void __w1_remove_master_device(struct w1_master *dev)

if (msleep_interruptible(1000))
flush_signals(current);
+ w1_process_callbacks(dev);
}
+ w1_process_callbacks(dev);

memset(&msg, 0, sizeof(msg));
msg.id.mst.id = dev->id;
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index 747174b..06d614a 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -119,10 +119,12 @@ static int w1_get_slaves(struct w1_master *dev,

if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
__u64 rn;
+ mutex_lock(&dev->list_mutex);
list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
memcpy(&rn, &sl->reg_num, sizeof(rn));
w1_send_slave(dev, rn);
}
+ mutex_unlock(&dev->list_mutex);
} else {
w1_search_process_cb(dev, cmd->cmd == W1_CMD_ALARM_SEARCH ?
W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
@@ -368,29 +370,134 @@ static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rm
return error;
}

+/* Bundle together a reference count, the full message, and broken out
+ * commands to be executed on each w1 master kthread in one memory allocation.
+ */
+struct w1_cb_block {
+ atomic_t refcnt;
+ struct cn_msg msg;
+ /* cn_msg data */
+ /* one or more variable length struct w1_cb_node */
+};
+struct w1_cb_node {
+ struct w1_async_cmd async;
+ /* pointers within w1_cb_block and msg data */
+ struct w1_cb_block *block;
+ struct w1_netlink_msg *m;
+ struct w1_slave *sl;
+ struct w1_master *dev;
+};
+
+static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
+{
+ struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
+ async);
+ u16 mlen = node->m->len;
+ u8 *cmd_data = node->m->data;
+ int err = 0;
+ struct w1_slave *sl = node->sl;
+ struct w1_netlink_cmd *cmd = NULL;
+
+ mutex_lock(&dev->mutex);
+ if (sl && w1_reset_select_slave(sl))
+ err = -ENODEV;
+
+ while (mlen && !err) {
+ cmd = (struct w1_netlink_cmd *)cmd_data;
+
+ if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
+ err = -E2BIG;
+ break;
+ }
+
+ if (sl)
+ err = w1_process_command_slave(sl, &node->block->msg,
+ node->m, cmd);
+ else
+ err = w1_process_command_master(dev, &node->block->msg,
+ node->m, cmd);
+
+ w1_netlink_send_error(&node->block->msg, node->m, cmd, err);
+ err = 0;
+
+ cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
+ mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
+ }
+
+ if (!cmd || err)
+ w1_netlink_send_error(&node->block->msg, node->m, cmd, err);
+
+ if (sl)
+ w1_unref_slave(sl);
+ else
+ atomic_dec(&dev->refcnt);
+ mutex_unlock(&dev->mutex);
+
+ mutex_lock(&dev->list_mutex);
+ list_del(&async_cmd->async_entry);
+ mutex_unlock(&dev->list_mutex);
+
+ if (atomic_sub_return(1, &node->block->refcnt) == 0)
+ kfree(node->block);
+}
+
static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
{
struct w1_netlink_msg *m = (struct w1_netlink_msg *)(msg + 1);
- struct w1_netlink_cmd *cmd;
struct w1_slave *sl;
struct w1_master *dev;
+ u16 msg_len;
int err = 0;
+ struct w1_cb_block *block = NULL;
+ struct w1_cb_node *node = NULL;
+ int node_count = 0;
+
+ /* Count the number of master or slave commands there are to allocate
+ * space for one cb_node each.
+ */
+ msg_len = msg->len;
+ while (msg_len && !err) {
+ if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
+ err = -E2BIG;
+ break;
+ }
+
+ if (m->type == W1_MASTER_CMD || m->type == W1_SLAVE_CMD)
+ ++node_count;
+
+ msg_len -= sizeof(struct w1_netlink_msg) + m->len;
+ m = (struct w1_netlink_msg *)(((u8 *)m) +
+ sizeof(struct w1_netlink_msg) + m->len);
+ }
+ m = (struct w1_netlink_msg *)(msg + 1);
+ if (node_count) {
+ /* msg->len doesn't include itself */
+ long size = sizeof(struct w1_cb_block) + msg->len +
+ node_count*sizeof(struct w1_cb_node);
+ block = kmalloc(size, GFP_KERNEL);
+ if (!block) {
+ w1_netlink_send_error(msg, m, NULL, -ENOMEM);
+ return;
+ }
+ atomic_set(&block->refcnt, 1);
+ memcpy(&block->msg, msg, sizeof(*msg) + msg->len);
+ node = (struct w1_cb_node *)((u8 *)block->msg.data + msg->len);
+ }

- while (msg->len && !err) {
+ msg_len = msg->len;
+ while (msg_len && !err) {
struct w1_reg_num id;
u16 mlen = m->len;
- u8 *cmd_data = m->data;

dev = NULL;
sl = NULL;
- cmd = NULL;

memcpy(&id, m->id.id, sizeof(id));
#if 0
printk("%s: %02x.%012llx.%02x: type=%02x, len=%u.\n",
__func__, id.family, (unsigned long long)id.id, id.crc, m->type, m->len);
#endif
- if (m->len + sizeof(struct w1_netlink_msg) > msg->len) {
+ if (m->len + sizeof(struct w1_netlink_msg) > msg_len) {
err = -E2BIG;
break;
}
@@ -415,41 +522,24 @@ static void w1_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
if (!mlen)
goto out_cont;

- mutex_lock(&dev->mutex);
+ atomic_inc(&block->refcnt);
+ node->async.cb = w1_process_cb;
+ node->block = block;
+ node->m = (struct w1_netlink_msg *)((u8 *)&block->msg +
+ (size_t)((u8 *)m - (u8 *)msg));
+ node->sl = sl;
+ node->dev = dev;

- if (sl && w1_reset_select_slave(sl)) {
- err = -ENODEV;
- goto out_up;
- }
-
- while (mlen) {
- cmd = (struct w1_netlink_cmd *)cmd_data;
-
- if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
- err = -E2BIG;
- break;
- }
-
- if (sl)
- err = w1_process_command_slave(sl, msg, m, cmd);
- else
- err = w1_process_command_master(dev, msg, m, cmd);
+ mutex_lock(&dev->list_mutex);
+ list_add_tail(&node->async.async_entry, &dev->async_list);
+ wake_up_process(dev->thread);
+ mutex_unlock(&dev->list_mutex);
+ ++node;

- w1_netlink_send_error(msg, m, cmd, err);
- err = 0;
-
- cmd_data += cmd->len + sizeof(struct w1_netlink_cmd);
- mlen -= cmd->len + sizeof(struct w1_netlink_cmd);
- }
-out_up:
- atomic_dec(&dev->refcnt);
- if (sl)
- atomic_dec(&sl->refcnt);
- mutex_unlock(&dev->mutex);
out_cont:
- if (!cmd || err)
- w1_netlink_send_error(msg, m, cmd, err);
- msg->len -= sizeof(struct w1_netlink_msg) + m->len;
+ if (err)
+ w1_netlink_send_error(msg, m, NULL, err);
+ msg_len -= sizeof(struct w1_netlink_msg) + m->len;
m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);

/*
@@ -458,6 +548,8 @@ out_cont:
if (err == -ENODEV)
err = 0;
}
+ if (block && atomic_sub_return(1, &block->refcnt) == 0)
+ kfree(block);
}

int w1_init_netlink(void)
--
1.7.10.4