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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-24 10:16:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-24 10:16:26 -0700
commit6c5103890057b1bb781b26b7aae38d33e4c517d8 (patch)
treee6e57961dcddcb5841acb34956e70b9dc696a880 /mm/filemap.c
parent3dab04e6978e358ad2307bca563fabd6c5d2c58b (diff)
parent9d2e157d970a73b3f270b631828e03eb452d525e (diff)
Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c74
1 files changed, 13 insertions, 61 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index f807afda86f2..04d1992fd86b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -164,45 +164,15 @@ void delete_from_page_cache(struct page *page)
}
EXPORT_SYMBOL(delete_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;
}
@@ -558,12 +528,6 @@ 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
@@ -591,7 +555,7 @@ 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);
@@ -655,17 +619,12 @@ 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);
@@ -675,24 +634,10 @@ 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)
{
@@ -1407,12 +1352,15 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long seg = 0;
size_t count;
loff_t *ppos = &iocb->ki_pos;
+ struct blk_plug plug;
count = 0;
retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
if (retval)
return retval;
+ blk_start_plug(&plug);
+
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
if (filp->f_flags & O_DIRECT) {
loff_t size;
@@ -1485,6 +1433,7 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
break;
}
out:
+ blk_finish_plug(&plug);
return retval;
}
EXPORT_SYMBOL(generic_file_aio_read);
@@ -2596,11 +2545,13 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
+ struct blk_plug plug;
ssize_t ret;
BUG_ON(iocb->ki_pos != pos);
mutex_lock(&inode->i_mutex);
+ blk_start_plug(&plug);
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
@@ -2611,6 +2562,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (err < 0 && ret > 0)
ret = err;
}
+ blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(generic_file_aio_write);