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

3 files changed, 20 insertions, 5 deletions

diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
index 02df3b1381d2..b077b8b42758 100644
--- a/drivers/w1/masters/ds1wm.c
+++ b/drivers/w1/masters/ds1wm.c
@@ -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);
 }
 
 /* --------------------------------------------------------------------- */
diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c
index db0bf3229bb6..7404ad3062b7 100644
--- a/drivers/w1/masters/ds2490.c
+++ b/drivers/w1/masters/ds2490.c
@@ -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
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index a5dc21934cf2..5234964fe001 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -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);