Commit 42105698 authored by David Fries's avatar David Fries Committed by Greg Kroah-Hartman
Browse files

w1: fixup search to support abort from netlink 



Before 63706172 "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.  9d1817ca
"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: default avatarDavid Fries <David@Fries.net>
Acked-by: default avatarEvgeniy Polyakov <zbr@ioremap.net>
Cc: Marcin Jurkowski <marcin1j@gmail.com>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: Sven Geggus <lists@fuchsschwanzdomain.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6b355b33

drivers/w1/w1.c

+1 −2
Original line number Diff line number Diff line
@@ -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;

drivers/w1/w1.h

+10 −0
Original line number Diff line number Diff line
@@ -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;

drivers/w1/w1_int.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

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