Revision d58b0d980f0b1c27204da0e05537b606da45a07f authored by Linus Torvalds on 04 August 2016, 23:56:16 UTC, committed by Linus Torvalds on 04 August 2016, 23:56:16 UTC
Pull more btrfs updates from Chris Mason:
 "This is part two of my btrfs pull, which is some cleanups and a batch
  of fixes.

  Most of the code here is from Jeff Mahoney, making the pointers we
  pass around internally more consistent and less confusing overall.  I
  noticed a small problem right before I sent this out yesterday, so I
  fixed it up and re-tested overnight"

* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (40 commits)
  Btrfs: fix __MAX_CSUM_ITEMS
  btrfs: btrfs_abort_transaction, drop root parameter
  btrfs: add btrfs_trans_handle->fs_info pointer
  btrfs: btrfs_relocate_chunk pass extent_root to btrfs_end_transaction
  btrfs: convert nodesize macros to static inlines
  btrfs: introduce BTRFS_MAX_ITEM_SIZE
  btrfs: cleanup, remove prototype for btrfs_find_root_ref
  btrfs: copy_to_sk drop unused root parameter
  btrfs: simpilify btrfs_subvol_inherit_props
  btrfs: tests, use BTRFS_FS_STATE_DUMMY_FS_INFO instead of dummy root
  btrfs: tests, require fs_info for root
  btrfs: tests, move initialization into tests/
  btrfs: btrfs_test_opt and friends should take a btrfs_fs_info
  btrfs: prefix fsid to all trace events
  btrfs: plumb fs_info into btrfs_work
  btrfs: remove obsolete part of comment in statfs
  btrfs: hide test-only member under ifdef
  btrfs: Ratelimit "no csum found" info message
  btrfs: Add ratelimit to btrfs printing
  Btrfs: fix unexpected balance crash due to BUG_ON
  ...
2 parent s 3a30325 + 42049bf
Raw File
once.c
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/once.h>
#include <linux/random.h>

struct once_work {
	struct work_struct work;
	struct static_key *key;
};

static void once_deferred(struct work_struct *w)
{
	struct once_work *work;

	work = container_of(w, struct once_work, work);
	BUG_ON(!static_key_enabled(work->key));
	static_key_slow_dec(work->key);
	kfree(work);
}

static void once_disable_jump(struct static_key *key)
{
	struct once_work *w;

	w = kmalloc(sizeof(*w), GFP_ATOMIC);
	if (!w)
		return;

	INIT_WORK(&w->work, once_deferred);
	w->key = key;
	schedule_work(&w->work);
}

static DEFINE_SPINLOCK(once_lock);

bool __do_once_start(bool *done, unsigned long *flags)
	__acquires(once_lock)
{
	spin_lock_irqsave(&once_lock, *flags);
	if (*done) {
		spin_unlock_irqrestore(&once_lock, *flags);
		/* Keep sparse happy by restoring an even lock count on
		 * this lock. In case we return here, we don't call into
		 * __do_once_done but return early in the DO_ONCE() macro.
		 */
		__acquire(once_lock);
		return false;
	}

	return true;
}
EXPORT_SYMBOL(__do_once_start);

void __do_once_done(bool *done, struct static_key *once_key,
		    unsigned long *flags)
	__releases(once_lock)
{
	*done = true;
	spin_unlock_irqrestore(&once_lock, *flags);
	once_disable_jump(once_key);
}
EXPORT_SYMBOL(__do_once_done);
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