w1: optional bundling of netlink kernel replies

Applications can submit a set of commands in one packet to the kernel,
and in some cases it is required such as reading the temperature
sensor results.  This adds an option W1_CN_BUNDLE to the flags of
cn_msg to request the kernel to reply in one packet for efficiency.

The cn_msg flags now check for unknown flag values and return an error
if one is seen.  See "Proper handling of unknown flags in system
calls" http://lwn.net/Articles/588444/

This corrects the ack values returned as per the protocol standard,
namely the original ack for status messages and seq + 1 for all others
such as the data returned from a read.

Some of the common variable names have been standardized as follows.
struct cn_msg *cn
struct w1_netlink_msg *msg
struct w1_netlink_cmd *cmd
struct w1_master *dev

When an argument and a function scope variable would collide, add req_
to the argument.

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

2 files changed, 9 insertions, 6 deletions

diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic
index a31c5a242973..b2033c64c7da 100644
--- a/Documentation/w1/w1.generic
+++ b/Documentation/w1/w1.generic
@@ -82,7 +82,7 @@ driver             - (standard) symlink to the w1 driver
 w1_master_add      - Manually register a slave device
 w1_master_attempts - the number of times a search was attempted
 w1_master_max_slave_count
-                   - the maximum slaves that may be attached to a master
+                   - maximum number of slaves to search for at a time
 w1_master_name     - the name of the device (w1_bus_masterX)
 w1_master_pullup   - 5V strong pullup 0 enabled, 1 disabled
 w1_master_remove   - Manually remove a slave device
diff --git a/Documentation/w1/w1.netlink b/Documentation/w1/w1.netlink
index 927a52cc0519..ef2727192d69 100644
--- a/Documentation/w1/w1.netlink
+++ b/Documentation/w1/w1.netlink
@@ -30,7 +30,7 @@ Protocol.
                         W1_SLAVE_CMD
                                 userspace command for slave device
                                 (read/write/touch)
-        __u8 res        - reserved
+        __u8 status     - error indication from kernel
         __u16 len       - size of data attached to this header data
         union {
                 __u8 id[8];                      - slave unique device id
@@ -44,10 +44,14 @@ Protocol.
         __u8 cmd        - command opcode.
                         W1_CMD_READ     - read command
                         W1_CMD_WRITE    - write command
-                        W1_CMD_TOUCH    - touch command
-                                (write and sample data back to userspace)
                         W1_CMD_SEARCH   - search command
                         W1_CMD_ALARM_SEARCH - alarm search command
+                        W1_CMD_TOUCH    - touch command
+                                (write and sample data back to userspace)
+                        W1_CMD_RESET    - send bus reset
+                        W1_CMD_SLAVE_ADD        - add slave to kernel list
+                        W1_CMD_SLAVE_REMOVE     - remove slave from kernel list
+                        W1_CMD_LIST_SLAVES      - get slaves list from kernel
         __u8 res        - reserved
         __u16 len       - length of data for this command
                 For read command data must be allocated like for write command
@@ -87,8 +91,7 @@ format:
         id0 ... idN
 
         Each message is at most 4k in size, so if number of master devices
-        exceeds this, it will be split into several messages,
-        cn.seq will be increased for each one.
+        exceeds this, it will be split into several messages.
 
 W1 search and alarm search commands.
 request: