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Commit ece8e0b2 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-3.9-async' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 

Pull async changes from Tejun Heo:
 "These are followups for the earlier deadlock issue involving async
  ending up waiting for itself through block requesting module[1].  The
  following changes are made by these commits.

   - Instead of requesting default elevator on each request_queue init,
     block now requests it once early during boot.

   - Kmod triggers warning if invoked from an async worker.

   - Async synchronization implementation has been reimplemented.  It's
     a lot simpler now."

* 'for-3.9-async' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  async: initialise list heads to fix crash
  async: replace list of active domains with global list of pending items
  async: keep pending tasks on async_domain and remove async_pending
  async: use ULLONG_MAX for infinity cookie value
  async: bring sanity to the use of words domain and running
  async, kmod: warn on synchronous request_module() from async workers
  block: don't request module during elevator init
  init, block: try to load default elevator module early during boot
parents 67cb104b a0327ff0

block/elevator.c

+28 −7
Original line number Diff line number Diff line
@@ -100,14 +100,14 @@ static void elevator_put(struct elevator_type *e) 
	module_put(e->elevator_owner);

}



static struct elevator_type *elevator_get(const char *name)

static struct elevator_type *elevator_get(const char *name, bool try_loading)

{

	struct elevator_type *e;



	spin_lock(&elv_list_lock);



	e = elevator_find(name);

	if (!e) {

	if (!e && try_loading) {

		spin_unlock(&elv_list_lock);

		request_module("%s-iosched", name);

		spin_lock(&elv_list_lock);
@@ -136,6 +136,22 @@ static int __init elevator_setup(char *str) 


__setup("elevator=", elevator_setup);



/* called during boot to load the elevator chosen by the elevator param */

void __init load_default_elevator_module(void)

{

	struct elevator_type *e;



	if (!chosen_elevator[0])

		return;



	spin_lock(&elv_list_lock);

	e = elevator_find(chosen_elevator);

	spin_unlock(&elv_list_lock);



	if (!e)

		request_module("%s-iosched", chosen_elevator);

}



static struct kobj_type elv_ktype;



static struct elevator_queue *elevator_alloc(struct request_queue *q,
@@ -191,25 +207,30 @@ int elevator_init(struct request_queue *q, char *name) 
	q->boundary_rq = NULL;



	if (name) {

		e = elevator_get(name);

		e = elevator_get(name, true);

		if (!e)

			return -EINVAL;

	}



	/*

	 * Use the default elevator specified by config boot param or

	 * config option.  Don't try to load modules as we could be running

	 * off async and request_module() isn't allowed from async.

	 */

	if (!e && *chosen_elevator) {

		e = elevator_get(chosen_elevator);

		e = elevator_get(chosen_elevator, false);

		if (!e)

			printk(KERN_ERR "I/O scheduler %s not found\n",

							chosen_elevator);

	}



	if (!e) {

		e = elevator_get(CONFIG_DEFAULT_IOSCHED);

		e = elevator_get(CONFIG_DEFAULT_IOSCHED, false);

		if (!e) {

			printk(KERN_ERR

				"Default I/O scheduler not found. " \

				"Using noop.\n");

			e = elevator_get("noop");

			e = elevator_get("noop", false);

		}

	}
@@ -951,7 +972,7 @@ int elevator_change(struct request_queue *q, const char *name) 
		return -ENXIO;



	strlcpy(elevator_name, name, sizeof(elevator_name));

	e = elevator_get(strstrip(elevator_name));

	e = elevator_get(strstrip(elevator_name), true);

	if (!e) {

		printk(KERN_ERR "elevator: type %s not found\n", elevator_name);

		return -EINVAL;

include/linux/async.h

+3 −6
Original line number Diff line number Diff line
@@ -19,8 +19,7 @@ typedef u64 async_cookie_t; 
typedef void (async_func_ptr) (void *data, async_cookie_t cookie);

struct async_domain {

	struct list_head node;

	struct list_head domain;

	int count;

	struct list_head pending;

	unsigned registered:1;

};
@@ -29,8 +28,7 @@ struct async_domain { 
 */

#define ASYNC_DOMAIN(_name) \

	struct async_domain _name = { .node = LIST_HEAD_INIT(_name.node), \

				      .domain = LIST_HEAD_INIT(_name.domain), \

				      .count = 0, \

				      .pending = LIST_HEAD_INIT(_name.pending), \

				      .registered = 1 }



/*
@@ -39,8 +37,7 @@ struct async_domain { 
 */

#define ASYNC_DOMAIN_EXCLUSIVE(_name) \

	struct async_domain _name = { .node = LIST_HEAD_INIT(_name.node), \

				      .domain = LIST_HEAD_INIT(_name.domain), \

				      .count = 0, \

				      .pending = LIST_HEAD_INIT(_name.pending), \

				      .registered = 0 }



extern async_cookie_t async_schedule(async_func_ptr *ptr, void *data);

include/linux/elevator.h

+5 −0
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ extern void elv_drain_elevator(struct request_queue *); 
/*

 * io scheduler registration

 */

extern void __init load_default_elevator_module(void);

extern int elv_register(struct elevator_type *);

extern void elv_unregister(struct elevator_type *);
@@ -206,5 +207,9 @@ enum { 
	INIT_LIST_HEAD(&(rq)->csd.list);	\

	} while (0)



#else /* CONFIG_BLOCK */



static inline void load_default_elevator_module(void) { }



#endif /* CONFIG_BLOCK */

#endif

include/linux/init.h

+1 −0
Original line number Diff line number Diff line
@@ -153,6 +153,7 @@ extern unsigned int reset_devices; 
/* used by init/main.c */

void setup_arch(char **);

void prepare_namespace(void);

void __init load_default_modules(void);



extern void (*late_time_init)(void);

init/do_mounts_initrd.c

+3 −0
Original line number Diff line number Diff line
@@ -61,6 +61,9 @@ static void __init handle_initrd(void) 
	sys_mkdir("/old", 0700);

	sys_chdir("/old");



	/* try loading default modules from initrd */

	load_default_modules();



	/*

	 * In case that a resume from disk is carried out by linuxrc or one of

	 * its children, we need to tell the freezer not to wait for us.