From d3a8a9dbb903c73a7ec2deae4c9b7d74b6834f4c Mon Sep 17 00:00:00 2001 From: David Fries Date: Wed, 15 Jan 2014 22:29:26 -0600 Subject: [PATCH] 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 Acked-by: Evgeniy Polyakov Signed-off-by: Greg Kroah-Hartman --- drivers/w1/masters/ds1wm.c | 4 +++- drivers/w1/masters/ds2490.c | 8 ++++++-- drivers/w1/w1_netlink.c | 13 +++++++++++-- 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); -- 2.39.2