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block: remove per-queue plugging

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Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Jens Axboe
2011-03-10 08:52:07 +01:00
parent 73c1010119
commit 7eaceaccab
119 changed files with 151 additions and 1269 deletions
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67
mm/filemap.c
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@@ -155,45 +155,15 @@ void remove_from_page_cache(struct page *page)
}
EXPORT_SYMBOL(remove_from_page_cache);
static int sync_page(void *word)
static int sleep_on_page(void *word)
{
struct address_space *mapping;
struct page *page;
page = container_of((unsigned long *)word, struct page, flags);
/*
* page_mapping() is being called without PG_locked held.
* Some knowledge of the state and use of the page is used to
* reduce the requirements down to a memory barrier.
* The danger here is of a stale page_mapping() return value
* indicating a struct address_space different from the one it's
* associated with when it is associated with one.
* After smp_mb(), it's either the correct page_mapping() for
* the page, or an old page_mapping() and the page's own
* page_mapping() has gone NULL.
* The ->sync_page() address_space operation must tolerate
* page_mapping() going NULL. By an amazing coincidence,
* this comes about because none of the users of the page
* in the ->sync_page() methods make essential use of the
* page_mapping(), merely passing the page down to the backing
* device's unplug functions when it's non-NULL, which in turn
* ignore it for all cases but swap, where only page_private(page) is
* of interest. When page_mapping() does go NULL, the entire
* call stack gracefully ignores the page and returns.
* -- wli
*/
smp_mb();
mapping = page_mapping(page);
if (mapping && mapping->a_ops && mapping->a_ops->sync_page)
mapping->a_ops->sync_page(page);
io_schedule();
return 0;
}
static int sync_page_killable(void *word)
static int sleep_on_page_killable(void *word)
{
sync_page(word);
sleep_on_page(word);
return fatal_signal_pending(current) ? -EINTR : 0;
}
@@ -479,12 +449,6 @@ struct page *__page_cache_alloc(gfp_t gfp)
EXPORT_SYMBOL(__page_cache_alloc);
#endif
static int __sleep_on_page_lock(void *word)
{
io_schedule();
return 0;
}
/*
* In order to wait for pages to become available there must be
* waitqueues associated with pages. By using a hash table of
@@ -512,7 +476,7 @@ void wait_on_page_bit(struct page *page, int bit_nr)
DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
if (test_bit(bit_nr, &page->flags))
__wait_on_bit(page_waitqueue(page), &wait, sync_page,
__wait_on_bit(page_waitqueue(page), &wait, sleep_on_page,
TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_on_page_bit);
@@ -576,17 +540,12 @@ EXPORT_SYMBOL(end_page_writeback);
/**
* __lock_page - get a lock on the page, assuming we need to sleep to get it
* @page: the page to lock
*
* Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some
* random driver's requestfn sets TASK_RUNNING, we could busywait. However
* chances are that on the second loop, the block layer's plug list is empty,
* so sync_page() will then return in state TASK_UNINTERRUPTIBLE.
*/
void __lock_page(struct page *page)
{
DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
__wait_on_bit_lock(page_waitqueue(page), &wait, sync_page,
__wait_on_bit_lock(page_waitqueue(page), &wait, sleep_on_page,
TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(__lock_page);
@@ -596,24 +555,10 @@ int __lock_page_killable(struct page *page)
DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
return __wait_on_bit_lock(page_waitqueue(page), &wait,
sync_page_killable, TASK_KILLABLE);
sleep_on_page_killable, TASK_KILLABLE);
}
EXPORT_SYMBOL_GPL(__lock_page_killable);
/**
* __lock_page_nosync - get a lock on the page, without calling sync_page()
* @page: the page to lock
*
* Variant of lock_page that does not require the caller to hold a reference
* on the page's mapping.
*/
void __lock_page_nosync(struct page *page)
{
DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
__wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock,
TASK_UNINTERRUPTIBLE);
}
int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
unsigned int flags)
{