[PATCH 06/14] w1: new netlink commands, add/remove/list slaves

David Fries
2013-12-29T06:54:01Z

Introduce new commands to add, remove, and list slave devices through
the netlink interface. This can be useful to skip the search on a
static network. They could previously only be added or removed
through automatic search or sysfs, and this allows a program to only
use netlink.

Only allocate memory when needed, so move kzalloc into w1_get_slaves
where it was used.

Signed-off-by: David Fries <David@Fries.net>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
---
drivers/w1/w1.c | 6 +--
drivers/w1/w1.h | 3 ++
drivers/w1/w1_netlink.c | 125 ++++++++++++++++++++++++++++++++++-------------
drivers/w1/w1_netlink.h | 31 +++++++++++-
4 files changed, 126 insertions(+), 39 deletions(-)

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 4c89f85..97b35cb 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -56,8 +56,6 @@ module_param_named(slave_ttl, w1_max_slave_ttl, int, 0);
DEFINE_MUTEX(w1_mlock);
LIST_HEAD(w1_masters);

-static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn);
-
static int w1_master_match(struct device *dev, struct device_driver *drv)
{
return 1;
@@ -444,7 +442,7 @@ 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
*/
-static struct w1_slave *w1_slave_search_device(struct w1_master *dev,
+struct w1_slave *w1_slave_search_device(struct w1_master *dev,
struct w1_reg_num *rn)
{
struct w1_slave *sl;
@@ -711,7 +709,7 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
return 0;
}

-static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
+int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
{
struct w1_slave *sl;
struct w1_family *f;
diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index 80fbdf9..3376bfb 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -213,6 +213,8 @@ struct w1_slave *w1_search_slave(struct w1_reg_num *id);
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);
+struct w1_slave *w1_slave_search_device(struct w1_master *dev,
+ struct w1_reg_num *rn);
struct w1_master *w1_search_master_id(u32 id);

/* Disconnect and reconnect devices in the given family. Used for finding
@@ -221,6 +223,7 @@ struct w1_master *w1_search_master_id(u32 id);
* has just been registered, to 0 when it has been unregistered.
*/
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);

u8 w1_triplet(struct w1_master *dev, int bdir);
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index 73705af..747174b 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -56,9 +56,6 @@ static void w1_send_slave(struct w1_master *dev, u64 rn)
int avail;
u64 *data;

- /* update kernel slave list */
- w1_slave_found(dev, rn);
-
avail = dev->priv_size - cmd->len;

if (avail < 8) {
@@ -79,17 +76,57 @@ static void w1_send_slave(struct w1_master *dev, u64 rn)
msg->len += 8;
}

-static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
- unsigned int avail)
+static void w1_found_send_slave(struct w1_master *dev, u64 rn)
{
- struct w1_netlink_msg *hdr = (struct w1_netlink_msg *)(msg + 1);
- struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)(hdr + 1);
- int search_type = (cmd->cmd == W1_CMD_ALARM_SEARCH)?W1_ALARM_SEARCH:W1_SEARCH;
+ /* update kernel slave list */
+ w1_slave_found(dev, rn);
+
+ w1_send_slave(dev, rn);
+}
+
+/* Get the current slave list, or search (with or without alarm) */
+static int w1_get_slaves(struct w1_master *dev,
+ struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
+ struct w1_netlink_cmd *req_cmd)
+{
+ struct cn_msg *msg;
+ struct w1_netlink_msg *hdr;
+ struct w1_netlink_cmd *cmd;
+ struct w1_slave *sl;
+
+ msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ msg->id = req_msg->id;
+ msg->seq = req_msg->seq;
+ msg->ack = 0;
+ msg->len = sizeof(struct w1_netlink_msg) +
+ sizeof(struct w1_netlink_cmd);
+
+ hdr = (struct w1_netlink_msg *)(msg + 1);
+ cmd = (struct w1_netlink_cmd *)(hdr + 1);
+
+ hdr->type = W1_MASTER_CMD;
+ hdr->id = req_hdr->id;
+ hdr->len = sizeof(struct w1_netlink_cmd);
+
+ cmd->cmd = req_cmd->cmd;
+ cmd->len = 0;

dev->priv = msg;
- dev->priv_size = avail;
+ dev->priv_size = PAGE_SIZE - msg->len - sizeof(struct cn_msg);

- w1_search_process_cb(dev, search_type, w1_send_slave);
+ if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
+ __u64 rn;
+ list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+ memcpy(&rn, &sl->reg_num, sizeof(rn));
+ w1_send_slave(dev, rn);
+ }
+ } else {
+ w1_search_process_cb(dev, cmd->cmd == W1_CMD_ALARM_SEARCH ?
+ W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
+ }

msg->ack = 0;
cn_netlink_send(msg, 0, GFP_KERNEL);
@@ -97,6 +134,8 @@ static int w1_process_search_command(struct w1_master *dev, struct cn_msg *msg,
dev->priv = NULL;
dev->priv_size = 0;

+ kfree(msg);
+
return 0;
}

@@ -164,38 +203,52 @@ static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
return err;
}

-static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_msg,
- struct w1_netlink_msg *req_hdr, struct w1_netlink_cmd *req_cmd)
+static int w1_process_command_addremove(struct w1_master *dev,
+ struct cn_msg *msg, struct w1_netlink_msg *hdr,
+ struct w1_netlink_cmd *cmd)
{
- int err = -EINVAL;
- struct cn_msg *msg;
- struct w1_netlink_msg *hdr;
- struct w1_netlink_cmd *cmd;
+ struct w1_slave *sl;
+ int err = 0;
+ struct w1_reg_num *id;

- msg = kzalloc(PAGE_SIZE, GFP_KERNEL);
- if (!msg)
- return -ENOMEM;
+ if (cmd->len != 8)
+ return -EINVAL;

- msg->id = req_msg->id;
- msg->seq = req_msg->seq;
- msg->ack = 0;
- msg->len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd);
+ id = (struct w1_reg_num *)cmd->data;

- hdr = (struct w1_netlink_msg *)(msg + 1);
- cmd = (struct w1_netlink_cmd *)(hdr + 1);
+ sl = w1_slave_search_device(dev, id);
+ switch (cmd->cmd) {
+ case W1_CMD_SLAVE_ADD:
+ if (sl)
+ err = -EINVAL;
+ else
+ err = w1_attach_slave_device(dev, id);
+ break;
+ case W1_CMD_SLAVE_REMOVE:
+ if (sl)
+ w1_slave_detach(sl);
+ else
+ err = -EINVAL;
+ break;
+ default:
+ err = -EINVAL;
+ break;
+ }

- hdr->type = W1_MASTER_CMD;
- hdr->id = req_hdr->id;
- hdr->len = sizeof(struct w1_netlink_cmd);
+ return err;
+}

- cmd->cmd = req_cmd->cmd;
- cmd->len = 0;
+static int w1_process_command_master(struct w1_master *dev,
+ struct cn_msg *req_msg, struct w1_netlink_msg *req_hdr,
+ struct w1_netlink_cmd *req_cmd)
+{
+ int err = -EINVAL;

- switch (cmd->cmd) {
+ switch (req_cmd->cmd) {
case W1_CMD_SEARCH:
case W1_CMD_ALARM_SEARCH:
- err = w1_process_search_command(dev, msg,
- PAGE_SIZE - msg->len - sizeof(struct cn_msg));
+ case W1_CMD_LIST_SLAVES:
+ err = w1_get_slaves(dev, req_msg, req_hdr, req_cmd);
break;
case W1_CMD_READ:
case W1_CMD_WRITE:
@@ -205,12 +258,16 @@ static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_m
case W1_CMD_RESET:
err = w1_reset_bus(dev);
break;
+ case W1_CMD_SLAVE_ADD:
+ case W1_CMD_SLAVE_REMOVE:
+ err = w1_process_command_addremove(dev, req_msg, req_hdr,
+ req_cmd);
+ break;
default:
err = -EINVAL;
break;
}

- kfree(msg);
return err;
}

diff --git a/drivers/w1/w1_netlink.h b/drivers/w1/w1_netlink.h
index b0922dc..ea9f3e4 100644
--- a/drivers/w1/w1_netlink.h
+++ b/drivers/w1/w1_netlink.h
@@ -27,6 +27,17 @@

#include "w1.h"

+/** enum w1_netlink_message_types - message type
+ *
+ * @W1_SLAVE_ADD: notification that a slave device was added
+ * @W1_SLAVE_REMOVE: notification that a slave device was removed
+ * @W1_MASTER_ADD: notification that a new bus master was added
+ * @W1_MASTER_REMOVE: notification that a bus masterwas removed
+ * @W1_MASTER_CMD: initiate operations on a specific master
+ * @W1_SLAVE_CMD: sends reset, selects the slave, then does a read/write/touch
+ * operation
+ * @W1_LIST_MASTERS: used to determine the bus master identifiers
+ */
enum w1_netlink_message_types {
W1_SLAVE_ADD = 0,
W1_SLAVE_REMOVE,
@@ -52,6 +63,21 @@ struct w1_netlink_msg
__u8 data[0];
};

+/** enum w1_commands - commands available for master or slave operations
+ * @W1_CMD_READ: read len bytes
+ * @W1_CMD_WRITE: write len bytes
+ * @W1_CMD_SEARCH: initiate a standard search, returns only the slave
+ * devices found during that search
+ * @W1_CMD_ALARM_SEARCH: search for devices that are currently alarming
+ * @W1_CMD_TOUCH: Touches a series of bytes.
+ * @W1_CMD_RESET: sends a bus reset on the given master
+ * @W1_CMD_SLAVE_ADD: adds a slave to the given master,
+ * 8 byte slave id at data[0]
+ * @W1_CMD_SLAVE_REMOVE: removes a slave to the given master,
+ * 8 byte slave id at data[0]
+ * @W1_CMD_LIST_SLAVES: list of slaves registered on this master
+ * @W1_CMD_MAX: number of available commands
+ */
enum w1_commands {
W1_CMD_READ = 0,
W1_CMD_WRITE,
@@ -59,7 +85,10 @@ enum w1_commands {
W1_CMD_ALARM_SEARCH,
W1_CMD_TOUCH,
W1_CMD_RESET,
- W1_CMD_MAX,
+ W1_CMD_SLAVE_ADD,
+ W1_CMD_SLAVE_REMOVE,
+ W1_CMD_LIST_SLAVES,
+ W1_CMD_MAX
};

struct w1_netlink_cmd
--
1.7.10.4