From 421056987620fecb43c22c558e127085c406b7ba Mon Sep 17 00:00:00 2001 From: David Fries Date: Wed, 15 Jan 2014 22:29:13 -0600 Subject: [PATCH] w1: fixup search to support abort from netlink Before 63706172f33 "rework kthread_stop()" kthread_should_stop() always returned false when called from a non-kthread task, after it would oops as a non-kthread didn't have that structure and netlink was calling search from a thread which wasn't a kthread. 9d1817cab2f030 "w1: fix oops when w1_search is called from netlink connector", modified the code to avoid calling kthread_stop from a netlink thread. Introduce a w1_master flag and bit W1_ABORT_SEARCH to identify abort to cleanly support both kthread and netlink search abort. A search can take seconds to run, so it is important to abort early if the hardware is removed in the middle of a search. Signed-off-by: David Fries Acked-by: Evgeniy Polyakov Cc: Marcin Jurkowski Cc: Josh Boyer Cc: Sven Geggus Signed-off-by: Greg Kroah-Hartman --- drivers/w1/w1.c | 3 +-- drivers/w1/w1.h | 10 ++++++++++ drivers/w1/w1_int.c | 2 ++ 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index 66efa96..67b6d5f 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -960,8 +960,7 @@ void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb tmp64 = (triplet_ret >> 2); rn |= (tmp64 << i); - /* ensure we're called from kthread and not by netlink callback */ - if (!dev->priv && kthread_should_stop()) { + if (test_bit(W1_ABORT_SEARCH, &dev->flags)) { mutex_unlock(&dev->bus_mutex); dev_dbg(&dev->dev, "Abort w1_search\n"); return; diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h index ca8081a..bc329d2 100644 --- a/drivers/w1/w1.h +++ b/drivers/w1/w1.h @@ -155,6 +155,14 @@ struct w1_bus_master u8, w1_slave_found_callback); }; +/** + * enum w1_master_flags - bitfields used in w1_master.flags + * @W1_ABORT_SEARCH: abort searching early on shutdown + */ +enum w1_master_flags { + W1_ABORT_SEARCH = 0, +}; + struct w1_master { struct list_head w1_master_entry; @@ -178,6 +186,8 @@ struct w1_master /** 5V strong pullup duration in milliseconds, zero disabled. */ int pullup_duration; + long flags; + struct task_struct *thread; struct mutex mutex; struct mutex bus_mutex; diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c index 590bd8a..423f3c2 100644 --- a/drivers/w1/w1_int.c +++ b/drivers/w1/w1_int.c @@ -172,6 +172,7 @@ int w1_add_master_device(struct w1_bus_master *master) #if 0 /* Thread cleanup code, not required currently. */ err_out_kill_thread: + set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); #endif err_out_rm_attr: @@ -187,6 +188,7 @@ void __w1_remove_master_device(struct w1_master *dev) struct w1_netlink_msg msg; struct w1_slave *sl, *sln; + set_bit(W1_ABORT_SEARCH, &dev->flags); kthread_stop(dev->thread); mutex_lock(&w1_mlock); -- 2.7.4