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Subject[w1] Send status messages after command processing.
Date
Send completion status of the commands to the userspace.
Message and protocol are described in the documentation.

Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
---
Documentation/w1/w1.netlink | 29 +++++++++++++++++++++++
drivers/w1/w1_netlink.c | 53 +++++++++++++++++++++++++++++++++++++-----
drivers/w1/w1_netlink.h | 2 +-
3 files changed, 76 insertions(+), 8 deletions(-)

diff --git a/Documentation/w1/w1.netlink b/Documentation/w1/w1.netlink
index 25721af..089e65e 100644
--- a/Documentation/w1/w1.netlink
+++ b/Documentation/w1/w1.netlink
@@ -118,6 +118,35 @@ W1 reset command.
id is equal to the bus master id to use for searching]
[w1_netlink_cmd cmd = W1_CMD_RESET]

+
+Command status replies.
+======================
+
+Each command (either root, master or slave with or without w1_netlink_cmd
+structure) will be 'acked' by the w1 core. Format of the reply is the same
+as request message except that length parameters do not account for data
+requested by the user, i.e. read/write/touch IO requests will not contain
+data, so w1_netlink_cmd.len will be 0, w1_netlink_msg.len will be size
+of the w1_netlink_cmd structure and cn_msg.len will be equal to the sum
+of the sizeof(struct w1_netlink_msg) and sizeof(struct w1_netlink_cmd).
+If reply is generated for master or root command (which do not have
+w1_netlink_cmd attached), reply will contain only cn_msg and w1_netlink_msg
+structires.
+
+w1_netlink_msg.status field will carry positive error value
+(EINVAL for example) or zero in case of success.
+
+All other fields in every structure will mirror the same parameters in the
+request message (except lengths as described above).
+
+Status reply is generated for every w1_netlink_cmd embedded in the
+w1_netlink_msg, if there are no w1_netlink_cmd structures,
+reply will be generated for the w1_netlink_msg.
+
+All w1_netlink_cmd command structures are handled in every w1_netlink_msg,
+even if there were errors, only length mismatch interrupts message processing.
+
+
Operation steps in w1 core when new command is received.
=======================================================

diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index e807265..7cb83ad 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -152,7 +152,7 @@ static int w1_process_command_io(struct w1_master *dev, struct cn_msg *msg,
w1_write_block(dev, cmd->data, cmd->len);
break;
default:
- err = -1;
+ err = -EINVAL;
break;
}

@@ -195,14 +195,13 @@ static int w1_process_command_master(struct w1_master *dev, struct cn_msg *req_m
case W1_CMD_READ:
case W1_CMD_WRITE:
case W1_CMD_TOUCH:
- err = w1_process_command_io(dev, msg, hdr, cmd);
+ err = w1_process_command_io(dev, req_msg, req_hdr, req_cmd);
break;
case W1_CMD_RESET:
err = w1_reset_bus(dev);
break;
default:
- cmd->res = EINVAL;
- cn_netlink_send(msg, 0, GFP_KERNEL);
+ err = -EINVAL;
break;
}

@@ -246,7 +245,7 @@ static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mc
w = (struct w1_netlink_msg *)(cn + 1);

w->type = W1_LIST_MASTERS;
- w->reserved = 0;
+ w->status = 0;
w->len = 0;
id = (u32 *)(w + 1);

@@ -273,6 +272,40 @@ static int w1_process_command_root(struct cn_msg *msg, struct w1_netlink_msg *mc
return 0;
}

+static int w1_netlink_send_error(struct cn_msg *rcmsg, struct w1_netlink_msg *rmsg,
+ struct w1_netlink_cmd *rcmd, int error)
+{
+ struct cn_msg *cmsg;
+ struct w1_netlink_msg *msg;
+ struct w1_netlink_cmd *cmd;
+
+ cmsg = kzalloc(sizeof(*msg) + sizeof(*cmd) + sizeof(*cmsg), GFP_KERNEL);
+ if (!cmsg)
+ return -ENOMEM;
+
+ msg = (struct w1_netlink_msg *)(cmsg + 1);
+ cmd = (struct w1_netlink_cmd *)(msg + 1);
+
+ memcpy(cmsg, rcmsg, sizeof(*cmsg));
+ cmsg->len = sizeof(*msg);
+
+ memcpy(msg, rmsg, sizeof(*msg));
+ msg->len = 0;
+ msg->status = (short)-error;
+
+ if (rcmd) {
+ memcpy(cmd, rcmd, sizeof(*cmd));
+ cmd->len = 0;
+ msg->len += sizeof(*cmd);
+ cmsg->len += sizeof(*cmd);
+ }
+
+ error = cn_netlink_send(cmsg, 0, GFP_KERNEL);
+ kfree(cmsg);
+
+ return error;
+}
+
static void w1_cn_callback(void *data)
{
struct cn_msg *msg = data;
@@ -289,6 +322,7 @@ static void w1_cn_callback(void *data)

dev = NULL;
sl = NULL;
+ cmd = NULL;

memcpy(&id, m->id.id, sizeof(id));
#if 0
@@ -336,9 +370,12 @@ static void w1_cn_callback(void *data)
}

if (sl)
- w1_process_command_slave(sl, msg, m, cmd);
+ err = w1_process_command_slave(sl, msg, m, cmd);
else
- w1_process_command_master(dev, msg, m, cmd);
+ err = w1_process_command_master(dev, msg, m, cmd);
+
+ 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);
@@ -349,6 +386,8 @@ out_up:
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;
m = (struct w1_netlink_msg *)(((u8 *)m) + sizeof(struct w1_netlink_msg) + m->len);

diff --git a/drivers/w1/w1_netlink.h b/drivers/w1/w1_netlink.h
index 68a4ff4..27e950f 100644
--- a/drivers/w1/w1_netlink.h
+++ b/drivers/w1/w1_netlink.h
@@ -40,7 +40,7 @@ enum w1_netlink_message_types {
struct w1_netlink_msg
{
__u8 type;
- __u8 reserved;
+ __u8 status;
__u16 len;
union {
__u8 id[8];
--
1.5.6.3


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