w1: new netlink commands, add/remove/list slaves

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>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 126 insertions, 39 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 4c89f85edfe6..97b35cb8b6da 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 80fbdf908919..3376bfbb10f4 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 73705aff53cb..747174be7b50 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 b0922dc29658..ea9f3e453621 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