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Commit 4037014e authored by Evgeniy Polyakov's avatar Evgeniy Polyakov Committed by Linus Torvalds
Browse files

w1: send status messages after command processing 



Send completion status of the commands to the userspace.  Message and
protocol are described in the documentation.

Signed-off-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
Cc: Paul Alfille <paul.alfille@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f89735c4

Documentation/w1/w1.netlink

+29 −0
Original line number Diff line number Diff line
@@ -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.

=======================================================

drivers/w1/w1_netlink.c

+46 −7
Original line number Diff line number Diff line
@@ -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 @@ static void w1_cn_callback(void *data) 
			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);

drivers/w1/w1_netlink.h

+1 −1
Original line number Diff line number Diff line
@@ -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];