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Commit d3a8a9db authored by David Fries's avatar David Fries Committed by Greg Kroah-Hartman
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w1: hold bus_mutex in netlink and search 



The bus_mutex needs to be taken to serialize access to a specific bus.
netlink wasn't updated when bus_mutex was added and was calling
without that lock held, and not all of the masters were holding the
bus_mutex in a search.  This was causing the ds2490 hardware to stop
responding when both netlink and /sys slaves were executing bus
commands at the same time.

Signed-off-by: default avatarDavid Fries <David@Fries.net>
Acked-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b3be177a

drivers/w1/masters/ds1wm.c

+3 −1
Original line number Diff line number Diff line
@@ -326,13 +326,14 @@ static void ds1wm_search(void *data, struct w1_master *master_dev, 
	unsigned slaves_found = 0;

	unsigned int pass = 0;



	mutex_lock(&master_dev->bus_mutex);

	dev_dbg(&ds1wm_data->pdev->dev, "search begin\n");

	while (true) {

		++pass;

		if (pass > 100) {

			dev_dbg(&ds1wm_data->pdev->dev,

				"too many attempts (100), search aborted\n");

			return;

			break;

		}



		mutex_lock(&master_dev->bus_mutex);
@@ -439,6 +440,7 @@ static void ds1wm_search(void *data, struct w1_master *master_dev, 
	dev_dbg(&ds1wm_data->pdev->dev,

		"pass: %d total: %d search done ms d bit pos: %d\n", pass,

		slaves_found, ms_discrep_bit);

	mutex_unlock(&master_dev->bus_mutex);

}



/* --------------------------------------------------------------------- */

drivers/w1/masters/ds2490.c

+6 −2
Original line number Diff line number Diff line
@@ -727,9 +727,11 @@ static void ds9490r_search(void *data, struct w1_master *master, 
	 */

	u64 buf[2*64/8];



	mutex_lock(&master->bus_mutex);



	/* address to start searching at */

	if (ds_send_data(dev, (u8 *)&master->search_id, 8) < 0)

		return;

		goto search_out;

	master->search_id = 0;



	value = COMM_SEARCH_ACCESS | COMM_IM | COMM_RST | COMM_SM | COMM_F |
@@ -739,7 +741,7 @@ static void ds9490r_search(void *data, struct w1_master *master, 
		search_limit = 0;

	index = search_type | (search_limit << 8);

	if (ds_send_control(dev, value, index) < 0)

		return;

		goto search_out;



	do {

		schedule_timeout(jtime);
@@ -791,6 +793,8 @@ static void ds9490r_search(void *data, struct w1_master *master, 
			master->max_slave_count);

		set_bit(W1_WARN_MAX_COUNT, &master->flags);

	}

search_out:

	mutex_unlock(&master->bus_mutex);

}



#if 0

drivers/w1/w1_netlink.c

+11 −2
Original line number Diff line number Diff line
@@ -246,11 +246,16 @@ static int w1_process_command_master(struct w1_master *dev, 
{

	int err = -EINVAL;



	/* drop bus_mutex for search (does it's own locking), and add/remove

	 * which doesn't use the bus

	 */

	switch (req_cmd->cmd) {

	case W1_CMD_SEARCH:

	case W1_CMD_ALARM_SEARCH:

	case W1_CMD_LIST_SLAVES:

		mutex_unlock(&dev->bus_mutex);

		err = w1_get_slaves(dev, req_msg, req_hdr, req_cmd);

		mutex_lock(&dev->bus_mutex);

		break;

	case W1_CMD_READ:

	case W1_CMD_WRITE:
@@ -262,8 +267,12 @@ static int w1_process_command_master(struct w1_master *dev, 
		break;

	case W1_CMD_SLAVE_ADD:

	case W1_CMD_SLAVE_REMOVE:

		mutex_unlock(&dev->bus_mutex);

		mutex_lock(&dev->mutex);

		err = w1_process_command_addremove(dev, req_msg, req_hdr,

			req_cmd);

		mutex_unlock(&dev->mutex);

		mutex_lock(&dev->bus_mutex);

		break;

	default:

		err = -EINVAL;
@@ -400,7 +409,7 @@ static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd) 
	struct w1_slave *sl = node->sl;

	struct w1_netlink_cmd *cmd = NULL;



	mutex_lock(&dev->mutex);

	mutex_lock(&dev->bus_mutex);

	dev->portid = node->block->portid;

	if (sl && w1_reset_select_slave(sl))

		err = -ENODEV;
@@ -437,7 +446,7 @@ static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd) 
	else

		atomic_dec(&dev->refcnt);

	dev->portid = 0;

	mutex_unlock(&dev->mutex);

	mutex_unlock(&dev->bus_mutex);



	mutex_lock(&dev->list_mutex);

	list_del(&async_cmd->async_entry);