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

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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
This commit is contained in:
Linus Torvalds
2013-02-19 22:10:26 -08:00
parent 67cb104b4c a0327ff0ed
commit ece8e0b2f9
9 changed files with 132 additions and 111 deletions
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35
block/elevator.c
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@@ -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;