sched: Remove proliferation of wait_on_bit() action functions

The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Documentation/filesystems/caching/operations.txt b/Documentation/filesystems/caching/operations.txt
index bee2a5f..a1c052c 100644
--- a/Documentation/filesystems/caching/operations.txt
+++ b/Documentation/filesystems/caching/operations.txt
@@ -90,7 +90,7 @@
      to be cleared before proceeding:
 
 		wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
-			    fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 
 
  (2) The operation may be fast asynchronous (FSCACHE_OP_FAST), in which case it
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 4e84095..96c92b7 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -615,16 +615,6 @@
 }
 
 /*
- * This function is called when wait_on_bit is actually waiting.
- */
-static int do_io_schedule(void *word)
-{
-	io_schedule();
-
-	return 0;
-}
-
-/*
  * Initiate a write on a dirty buffer, but don't wait for it.
  *
  * - If the buffer is not dirty, exit.
@@ -640,8 +630,7 @@
 		return;
 
 	clear_bit(B_DIRTY, &b->state);
-	wait_on_bit_lock(&b->state, B_WRITING,
-			 do_io_schedule, TASK_UNINTERRUPTIBLE);
+	wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
 
 	if (!write_list)
 		submit_io(b, WRITE, b->block, write_endio);
@@ -675,9 +664,9 @@
 	if (!b->state)	/* fast case */
 		return;
 
-	wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
 	__write_dirty_buffer(b, NULL);
-	wait_on_bit(&b->state, B_WRITING, do_io_schedule, TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
 }
 
 /*
@@ -1030,7 +1019,7 @@
 	if (need_submit)
 		submit_io(b, READ, b->block, read_endio);
 
-	wait_on_bit(&b->state, B_READING, do_io_schedule, TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
 
 	if (b->read_error) {
 		int error = b->read_error;
@@ -1209,15 +1198,13 @@
 				dropped_lock = 1;
 				b->hold_count++;
 				dm_bufio_unlock(c);
-				wait_on_bit(&b->state, B_WRITING,
-					    do_io_schedule,
-					    TASK_UNINTERRUPTIBLE);
+				wait_on_bit_io(&b->state, B_WRITING,
+					       TASK_UNINTERRUPTIBLE);
 				dm_bufio_lock(c);
 				b->hold_count--;
 			} else
-				wait_on_bit(&b->state, B_WRITING,
-					    do_io_schedule,
-					    TASK_UNINTERRUPTIBLE);
+				wait_on_bit_io(&b->state, B_WRITING,
+					       TASK_UNINTERRUPTIBLE);
 		}
 
 		if (!test_bit(B_DIRTY, &b->state) &&
@@ -1321,15 +1308,15 @@
 
 	__write_dirty_buffer(b, NULL);
 	if (b->hold_count == 1) {
-		wait_on_bit(&b->state, B_WRITING,
-			    do_io_schedule, TASK_UNINTERRUPTIBLE);
+		wait_on_bit_io(&b->state, B_WRITING,
+			       TASK_UNINTERRUPTIBLE);
 		set_bit(B_DIRTY, &b->state);
 		__unlink_buffer(b);
 		__link_buffer(b, new_block, LIST_DIRTY);
 	} else {
 		sector_t old_block;
-		wait_on_bit_lock(&b->state, B_WRITING,
-				 do_io_schedule, TASK_UNINTERRUPTIBLE);
+		wait_on_bit_lock_io(&b->state, B_WRITING,
+				    TASK_UNINTERRUPTIBLE);
 		/*
 		 * Relink buffer to "new_block" so that write_callback
 		 * sees "new_block" as a block number.
@@ -1341,8 +1328,8 @@
 		__unlink_buffer(b);
 		__link_buffer(b, new_block, b->list_mode);
 		submit_io(b, WRITE, new_block, write_endio);
-		wait_on_bit(&b->state, B_WRITING,
-			    do_io_schedule, TASK_UNINTERRUPTIBLE);
+		wait_on_bit_io(&b->state, B_WRITING,
+			       TASK_UNINTERRUPTIBLE);
 		__unlink_buffer(b);
 		__link_buffer(b, old_block, b->list_mode);
 	}
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 5bd2290..864b03f 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1032,21 +1032,13 @@
 		snapshot_merge_next_chunks(s);
 }
 
-static int wait_schedule(void *ptr)
-{
-	schedule();
-
-	return 0;
-}
-
 /*
  * Stop the merging process and wait until it finishes.
  */
 static void stop_merge(struct dm_snapshot *s)
 {
 	set_bit(SHUTDOWN_MERGE, &s->state_bits);
-	wait_on_bit(&s->state_bits, RUNNING_MERGE, wait_schedule,
-		    TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&s->state_bits, RUNNING_MERGE, TASK_UNINTERRUPTIBLE);
 	clear_bit(SHUTDOWN_MERGE, &s->state_bits);
 }
 
diff --git a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c
index e355806..f296394 100644
--- a/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c
+++ b/drivers/media/usb/dvb-usb-v2/dvb_usb_core.c
@@ -253,13 +253,6 @@
 	return usb_urb_exitv2(&adap->stream);
 }
 
-static int wait_schedule(void *ptr)
-{
-	schedule();
-
-	return 0;
-}
-
 static int dvb_usb_start_feed(struct dvb_demux_feed *dvbdmxfeed)
 {
 	struct dvb_usb_adapter *adap = dvbdmxfeed->demux->priv;
@@ -273,8 +266,7 @@
 			dvbdmxfeed->pid, dvbdmxfeed->index);
 
 	/* wait init is done */
-	wait_on_bit(&adap->state_bits, ADAP_INIT, wait_schedule,
-			TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&adap->state_bits, ADAP_INIT, TASK_UNINTERRUPTIBLE);
 
 	if (adap->active_fe == -1)
 		return -EINVAL;
@@ -568,7 +560,7 @@
 
 	if (!adap->suspend_resume_active) {
 		set_bit(ADAP_SLEEP, &adap->state_bits);
-		wait_on_bit(&adap->state_bits, ADAP_STREAMING, wait_schedule,
+		wait_on_bit(&adap->state_bits, ADAP_STREAMING,
 				TASK_UNINTERRUPTIBLE);
 	}
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index a389820..3e11aab 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3437,16 +3437,10 @@
 	return 0;
 }
 
-static int eb_wait(void *word)
-{
-	io_schedule();
-	return 0;
-}
-
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
 {
-	wait_on_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK, eb_wait,
-		    TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
+		       TASK_UNINTERRUPTIBLE);
 }
 
 static noinline_for_stack int
diff --git a/fs/buffer.c b/fs/buffer.c
index eba6e4f..8f05111 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -61,16 +61,9 @@
 }
 EXPORT_SYMBOL(touch_buffer);
 
-static int sleep_on_buffer(void *word)
-{
-	io_schedule();
-	return 0;
-}
-
 void __lock_buffer(struct buffer_head *bh)
 {
-	wait_on_bit_lock(&bh->b_state, BH_Lock, sleep_on_buffer,
-							TASK_UNINTERRUPTIBLE);
+	wait_on_bit_lock_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__lock_buffer);
 
@@ -123,7 +116,7 @@
  */
 void __wait_on_buffer(struct buffer_head * bh)
 {
-	wait_on_bit(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE);
+	wait_on_bit_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__wait_on_buffer);
 
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 20d75b8..b98366f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3934,13 +3934,6 @@
 	return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
 }
 
-static int
-cifs_sb_tcon_pending_wait(void *unused)
-{
-	schedule();
-	return signal_pending(current) ? -ERESTARTSYS : 0;
-}
-
 /* find and return a tlink with given uid */
 static struct tcon_link *
 tlink_rb_search(struct rb_root *root, kuid_t uid)
@@ -4039,11 +4032,10 @@
 	} else {
 wait_for_construction:
 		ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
-				  cifs_sb_tcon_pending_wait,
 				  TASK_INTERRUPTIBLE);
 		if (ret) {
 			cifs_put_tlink(tlink);
-			return ERR_PTR(ret);
+			return ERR_PTR(-ERESTARTSYS);
 		}
 
 		/* if it's good, return it */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e90a1e9..b88b1ad 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3618,13 +3618,6 @@
 	return rc;
 }
 
-static int
-cifs_pending_writers_wait(void *unused)
-{
-	schedule();
-	return 0;
-}
-
 void cifs_oplock_break(struct work_struct *work)
 {
 	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
@@ -3636,7 +3629,7 @@
 	int rc = 0;
 
 	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
-			cifs_pending_writers_wait, TASK_UNINTERRUPTIBLE);
+			TASK_UNINTERRUPTIBLE);
 
 	server->ops->downgrade_oplock(server, cinode,
 		test_bit(CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2, &cinode->flags));
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index a174605..213c458 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1794,8 +1794,8 @@
 	int rc;
 	unsigned long *flags = &CIFS_I(inode)->flags;
 
-	rc = wait_on_bit_lock(flags, CIFS_INO_LOCK, cifs_wait_bit_killable,
-				TASK_KILLABLE);
+	rc = wait_on_bit_lock_action(flags, CIFS_INO_LOCK, cifs_wait_bit_killable,
+				     TASK_KILLABLE);
 	if (rc)
 		return rc;
 
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 3b0c62e..6bf55d0 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -582,7 +582,7 @@
 
 start:
 	rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
-				   cifs_oplock_break_wait, TASK_KILLABLE);
+			 TASK_KILLABLE);
 	if (rc)
 		return rc;
 
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index be568b7..ef9bef1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -342,7 +342,8 @@
 	wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
 	while (inode->i_state & I_SYNC) {
 		spin_unlock(&inode->i_lock);
-		__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
+		__wait_on_bit(wqh, &wq, bit_wait,
+			      TASK_UNINTERRUPTIBLE);
 		spin_lock(&inode->i_lock);
 	}
 }
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index aec01be..89acec7 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -160,7 +160,7 @@
 	_enter("%p", cookie);
 
 	wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK,
-			 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+			 TASK_UNINTERRUPTIBLE);
 
 	if (test_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags))
 		goto out_unlock;
@@ -255,7 +255,7 @@
 	if (!fscache_defer_lookup) {
 		_debug("non-deferred lookup %p", &cookie->flags);
 		wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
-			    fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 		_debug("complete");
 		if (test_bit(FSCACHE_COOKIE_UNAVAILABLE, &cookie->flags))
 			goto unavailable;
@@ -463,7 +463,6 @@
 	_enter("%p", cookie);
 
 	wait_on_bit(&cookie->flags, FSCACHE_COOKIE_INVALIDATING,
-		    fscache_wait_bit_interruptible,
 		    TASK_UNINTERRUPTIBLE);
 
 	_leave("");
@@ -525,7 +524,7 @@
 	}
 
 	wait_on_bit_lock(&cookie->flags, FSCACHE_COOKIE_ENABLEMENT_LOCK,
-			 fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+			 TASK_UNINTERRUPTIBLE);
 	if (!test_and_clear_bit(FSCACHE_COOKIE_ENABLED, &cookie->flags))
 		goto out_unlock_enable;
 
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index bc6c08f..7872a62 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -97,8 +97,6 @@
 	return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
 }
 
-extern int fscache_wait_bit(void *);
-extern int fscache_wait_bit_interruptible(void *);
 extern int fscache_wait_atomic_t(atomic_t *);
 
 /*
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
index 63f868e..a31b83c 100644
--- a/fs/fscache/main.c
+++ b/fs/fscache/main.c
@@ -197,24 +197,6 @@
 module_exit(fscache_exit);
 
 /*
- * wait_on_bit() sleep function for uninterruptible waiting
- */
-int fscache_wait_bit(void *flags)
-{
-	schedule();
-	return 0;
-}
-
-/*
- * wait_on_bit() sleep function for interruptible waiting
- */
-int fscache_wait_bit_interruptible(void *flags)
-{
-	schedule();
-	return signal_pending(current);
-}
-
-/*
  * wait_on_atomic_t() sleep function for uninterruptible waiting
  */
 int fscache_wait_atomic_t(atomic_t *p)
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index ed70714..85332b9 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -298,7 +298,6 @@
 
 	jif = jiffies;
 	if (wait_on_bit(&cookie->flags, FSCACHE_COOKIE_LOOKING_UP,
-			fscache_wait_bit_interruptible,
 			TASK_INTERRUPTIBLE) != 0) {
 		fscache_stat(&fscache_n_retrievals_intr);
 		_leave(" = -ERESTARTSYS");
@@ -342,7 +341,6 @@
 	if (stat_op_waits)
 		fscache_stat(stat_op_waits);
 	if (wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
-			fscache_wait_bit_interruptible,
 			TASK_INTERRUPTIBLE) != 0) {
 		ret = fscache_cancel_op(op, do_cancel);
 		if (ret == 0)
@@ -351,7 +349,7 @@
 		/* it's been removed from the pending queue by another party,
 		 * so we should get to run shortly */
 		wait_on_bit(&op->flags, FSCACHE_OP_WAITING,
-			    fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 	}
 	_debug("<<< GO");
 
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index c355f73..770e167 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -856,27 +856,6 @@
 }
 
 /**
- * gfs2_glock_holder_wait
- * @word: unused
- *
- * This function and gfs2_glock_demote_wait both show up in the WCHAN
- * field. Thus I've separated these otherwise identical functions in
- * order to be more informative to the user.
- */
-
-static int gfs2_glock_holder_wait(void *word)
-{
-        schedule();
-        return 0;
-}
-
-static int gfs2_glock_demote_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
-/**
  * gfs2_glock_wait - wait on a glock acquisition
  * @gh: the glock holder
  *
@@ -888,7 +867,7 @@
 	unsigned long time1 = jiffies;
 
 	might_sleep();
-	wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
 	if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
 		/* Lengthen the minimum hold time. */
 		gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
@@ -1128,7 +1107,7 @@
 	struct gfs2_glock *gl = gh->gh_gl;
 	gfs2_glock_dq(gh);
 	might_sleep();
-	wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
 }
 
 /**
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
index 91f274d..992ca5b 100644
--- a/fs/gfs2/lock_dlm.c
+++ b/fs/gfs2/lock_dlm.c
@@ -936,12 +936,6 @@
 	return error;
 }
 
-static int dlm_recovery_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
 static int control_first_done(struct gfs2_sbd *sdp)
 {
 	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
@@ -976,7 +970,7 @@
 		fs_info(sdp, "control_first_done wait gen %u\n", start_gen);
 
 		wait_on_bit(&ls->ls_recover_flags, DFL_DLM_RECOVERY,
-			    dlm_recovery_wait, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 		goto restart;
 	}
 
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index bc564c0..d3eae24 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1024,20 +1024,13 @@
 		lm->lm_unmount(sdp);
 }
 
-static int gfs2_journalid_wait(void *word)
-{
-	if (signal_pending(current))
-		return -EINTR;
-	schedule();
-	return 0;
-}
-
 static int wait_on_journal(struct gfs2_sbd *sdp)
 {
 	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
 		return 0;
 
-	return wait_on_bit(&sdp->sd_flags, SDF_NOJOURNALID, gfs2_journalid_wait, TASK_INTERRUPTIBLE);
+	return wait_on_bit(&sdp->sd_flags, SDF_NOJOURNALID, TASK_INTERRUPTIBLE)
+		? -EINTR : 0;
 }
 
 void gfs2_online_uevent(struct gfs2_sbd *sdp)
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 94555d4..573bd3b 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -591,12 +591,6 @@
 	wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
 }
 
-static int gfs2_recovery_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
 int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
 {
 	int rv;
@@ -609,7 +603,7 @@
 	BUG_ON(!rv);
 
 	if (wait)
-		wait_on_bit(&jd->jd_flags, JDF_RECOVERY, gfs2_recovery_wait,
+		wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
 			    TASK_UNINTERRUPTIBLE);
 
 	return wait ? jd->jd_recover_error : 0;
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 1319b5c..2607ff1 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -864,12 +864,6 @@
 	return error;
 }
 
-static int gfs2_umount_recovery_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
 /**
  * gfs2_put_super - Unmount the filesystem
  * @sb: The VFS superblock
@@ -894,7 +888,7 @@
 			continue;
 		spin_unlock(&sdp->sd_jindex_spin);
 		wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
-			    gfs2_umount_recovery_wait, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 		goto restart;
 	}
 	spin_unlock(&sdp->sd_jindex_spin);
diff --git a/fs/inode.c b/fs/inode.c
index 6eecb7f..5938f39 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1695,13 +1695,6 @@
 }
 EXPORT_SYMBOL(inode_needs_sync);
 
-int inode_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-EXPORT_SYMBOL(inode_wait);
-
 /*
  * If we try to find an inode in the inode hash while it is being
  * deleted, we have to wait until the filesystem completes its
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 6f0f590..5f09370 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -763,12 +763,6 @@
 	       bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
 }
 
-static int sleep_on_shadow_bh(void *word)
-{
-	io_schedule();
-	return 0;
-}
-
 /*
  * If the buffer is already part of the current transaction, then there
  * is nothing we need to do.  If it is already part of a prior
@@ -906,8 +900,8 @@
 		if (buffer_shadow(bh)) {
 			JBUFFER_TRACE(jh, "on shadow: sleep");
 			jbd_unlock_bh_state(bh);
-			wait_on_bit(&bh->b_state, BH_Shadow,
-				    sleep_on_shadow_bh, TASK_UNINTERRUPTIBLE);
+			wait_on_bit_io(&bh->b_state, BH_Shadow,
+				       TASK_UNINTERRUPTIBLE);
 			goto repeat;
 		}
 
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 4042ff5..524dd80 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -361,8 +361,8 @@
 	 * Prevent starvation issues if someone is doing a consistency
 	 * sync-to-disk
 	 */
-	ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
-			nfs_wait_bit_killable, TASK_KILLABLE);
+	ret = wait_on_bit_action(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
+				 nfs_wait_bit_killable, TASK_KILLABLE);
 	if (ret)
 		return ret;
 
diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c
index 44bf014..e2a0361 100644
--- a/fs/nfs/filelayout/filelayoutdev.c
+++ b/fs/nfs/filelayout/filelayoutdev.c
@@ -783,8 +783,8 @@
 static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
 {
 	might_sleep();
-	wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING,
-			nfs_wait_bit_killable, TASK_KILLABLE);
+	wait_on_bit_action(&ds->ds_state, NFS4DS_CONNECTING,
+			   nfs_wait_bit_killable, TASK_KILLABLE);
 }
 
 static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 9927913..b7b710e 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1074,8 +1074,8 @@
 	 * the bit lock here if it looks like we're going to be doing that.
 	 */
 	for (;;) {
-		ret = wait_on_bit(bitlock, NFS_INO_INVALIDATING,
-				  nfs_wait_bit_killable, TASK_KILLABLE);
+		ret = wait_on_bit_action(bitlock, NFS_INO_INVALIDATING,
+					 nfs_wait_bit_killable, TASK_KILLABLE);
 		if (ret)
 			goto out;
 		spin_lock(&inode->i_lock);
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 848f685..42f1211 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1251,8 +1251,8 @@
 	might_sleep();
 
 	atomic_inc(&clp->cl_count);
-	res = wait_on_bit(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING,
-			nfs_wait_bit_killable, TASK_KILLABLE);
+	res = wait_on_bit_action(&clp->cl_state, NFS4CLNT_MANAGER_RUNNING,
+				 nfs_wait_bit_killable, TASK_KILLABLE);
 	if (res)
 		goto out;
 	if (clp->cl_cons_state < 0)
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index b6ee3a6..6104d35 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -138,12 +138,6 @@
 	return __nfs_iocounter_wait(c);
 }
 
-static int nfs_wait_bit_uninterruptible(void *word)
-{
-	io_schedule();
-	return 0;
-}
-
 /*
  * nfs_page_group_lock - lock the head of the page group
  * @req - request in group that is to be locked
@@ -158,7 +152,6 @@
 	WARN_ON_ONCE(head != head->wb_head);
 
 	wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK,
-			nfs_wait_bit_uninterruptible,
 			TASK_UNINTERRUPTIBLE);
 }
 
@@ -425,9 +418,8 @@
 int
 nfs_wait_on_request(struct nfs_page *req)
 {
-	return wait_on_bit(&req->wb_flags, PG_BUSY,
-			nfs_wait_bit_uninterruptible,
-			TASK_UNINTERRUPTIBLE);
+	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
+			      TASK_UNINTERRUPTIBLE);
 }
 
 /*
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 6fdcd23..a8914b3 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1885,7 +1885,7 @@
 	if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
 		if (!sync)
 			goto out;
-		status = wait_on_bit_lock(&nfsi->flags,
+		status = wait_on_bit_lock_action(&nfsi->flags,
 				NFS_INO_LAYOUTCOMMITTING,
 				nfs_wait_bit_killable,
 				TASK_KILLABLE);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 98ff061..f05f321 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -397,7 +397,7 @@
 	int err;
 
 	/* Stop dirtying of new pages while we sync */
-	err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
+	err = wait_on_bit_lock_action(bitlock, NFS_INO_FLUSHING,
 			nfs_wait_bit_killable, TASK_KILLABLE);
 	if (err)
 		goto out_err;
@@ -1475,7 +1475,7 @@
 			return error;
 		if (!may_wait)
 			goto out_mark_dirty;
-		error = wait_on_bit(&NFS_I(inode)->flags,
+		error = wait_on_bit_action(&NFS_I(inode)->flags,
 				NFS_INO_COMMIT,
 				nfs_wait_bit_killable,
 				TASK_KILLABLE);
diff --git a/include/linux/wait.h b/include/linux/wait.h
index bd68819..73960ff 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -854,11 +854,14 @@
 		(wait)->flags = 0;					\
 	} while (0)
 
+
+extern int bit_wait(void *);
+extern int bit_wait_io(void *);
+
 /**
  * wait_on_bit - wait for a bit to be cleared
  * @word: the word being waited on, a kernel virtual address
  * @bit: the bit of the word being waited on
- * @action: the function used to sleep, which may take special actions
  * @mode: the task state to sleep in
  *
  * There is a standard hashed waitqueue table for generic use. This
@@ -867,9 +870,62 @@
  * call wait_on_bit() in threads waiting for the bit to clear.
  * One uses wait_on_bit() where one is waiting for the bit to clear,
  * but has no intention of setting it.
+ * Returned value will be zero if the bit was cleared, or non-zero
+ * if the process received a signal and the mode permitted wakeup
+ * on that signal.
  */
 static inline int
-wait_on_bit(void *word, int bit, int (*action)(void *), unsigned mode)
+wait_on_bit(void *word, int bit, unsigned mode)
+{
+	if (!test_bit(bit, word))
+		return 0;
+	return out_of_line_wait_on_bit(word, bit,
+				       bit_wait,
+				       mode);
+}
+
+/**
+ * wait_on_bit_io - wait for a bit to be cleared
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ * @mode: the task state to sleep in
+ *
+ * Use the standard hashed waitqueue table to wait for a bit
+ * to be cleared.  This is similar to wait_on_bit(), but calls
+ * io_schedule() instead of schedule() for the actual waiting.
+ *
+ * Returned value will be zero if the bit was cleared, or non-zero
+ * if the process received a signal and the mode permitted wakeup
+ * on that signal.
+ */
+static inline int
+wait_on_bit_io(void *word, int bit, unsigned mode)
+{
+	if (!test_bit(bit, word))
+		return 0;
+	return out_of_line_wait_on_bit(word, bit,
+				       bit_wait_io,
+				       mode);
+}
+
+/**
+ * wait_on_bit_action - wait for a bit to be cleared
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ * @action: the function used to sleep, which may take special actions
+ * @mode: the task state to sleep in
+ *
+ * Use the standard hashed waitqueue table to wait for a bit
+ * to be cleared, and allow the waiting action to be specified.
+ * This is like wait_on_bit() but allows fine control of how the waiting
+ * is done.
+ *
+ * Returned value will be zero if the bit was cleared, or non-zero
+ * if the process received a signal and the mode permitted wakeup
+ * on that signal.
+ */
+static inline int
+wait_on_bit_action(void *word, int bit, int (*action)(void *), unsigned mode)
 {
 	if (!test_bit(bit, word))
 		return 0;
@@ -880,7 +936,6 @@
  * wait_on_bit_lock - wait for a bit to be cleared, when wanting to set it
  * @word: the word being waited on, a kernel virtual address
  * @bit: the bit of the word being waited on
- * @action: the function used to sleep, which may take special actions
  * @mode: the task state to sleep in
  *
  * There is a standard hashed waitqueue table for generic use. This
@@ -891,9 +946,61 @@
  * wait_on_bit() in threads waiting to be able to set the bit.
  * One uses wait_on_bit_lock() where one is waiting for the bit to
  * clear with the intention of setting it, and when done, clearing it.
+ *
+ * Returns zero if the bit was (eventually) found to be clear and was
+ * set.  Returns non-zero if a signal was delivered to the process and
+ * the @mode allows that signal to wake the process.
  */
 static inline int
-wait_on_bit_lock(void *word, int bit, int (*action)(void *), unsigned mode)
+wait_on_bit_lock(void *word, int bit, unsigned mode)
+{
+	if (!test_and_set_bit(bit, word))
+		return 0;
+	return out_of_line_wait_on_bit_lock(word, bit, bit_wait, mode);
+}
+
+/**
+ * wait_on_bit_lock_io - wait for a bit to be cleared, when wanting to set it
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ * @mode: the task state to sleep in
+ *
+ * Use the standard hashed waitqueue table to wait for a bit
+ * to be cleared and then to atomically set it.  This is similar
+ * to wait_on_bit(), but calls io_schedule() instead of schedule()
+ * for the actual waiting.
+ *
+ * Returns zero if the bit was (eventually) found to be clear and was
+ * set.  Returns non-zero if a signal was delivered to the process and
+ * the @mode allows that signal to wake the process.
+ */
+static inline int
+wait_on_bit_lock_io(void *word, int bit, unsigned mode)
+{
+	if (!test_and_set_bit(bit, word))
+		return 0;
+	return out_of_line_wait_on_bit_lock(word, bit, bit_wait_io, mode);
+}
+
+/**
+ * wait_on_bit_lock_action - wait for a bit to be cleared, when wanting to set it
+ * @word: the word being waited on, a kernel virtual address
+ * @bit: the bit of the word being waited on
+ * @action: the function used to sleep, which may take special actions
+ * @mode: the task state to sleep in
+ *
+ * Use the standard hashed waitqueue table to wait for a bit
+ * to be cleared and then to set it, and allow the waiting action
+ * to be specified.
+ * This is like wait_on_bit() but allows fine control of how the waiting
+ * is done.
+ *
+ * Returns zero if the bit was (eventually) found to be clear and was
+ * set.  Returns non-zero if a signal was delivered to the process and
+ * the @mode allows that signal to wake the process.
+ */
+static inline int
+wait_on_bit_lock_action(void *word, int bit, int (*action)(void *), unsigned mode)
 {
 	if (!test_and_set_bit(bit, word))
 		return 0;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 5777c13..a219be9 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -90,7 +90,6 @@
  * fs/fs-writeback.c
  */	
 struct bdi_writeback;
-int inode_wait(void *);
 void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
 void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
 							enum wb_reason reason);
@@ -105,7 +104,7 @@
 static inline void wait_on_inode(struct inode *inode)
 {
 	might_sleep();
-	wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
+	wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE);
 }
 
 /*
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index adf9862..54e7522 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -28,12 +28,6 @@
 #include <linux/compat.h>
 
 
-static int ptrace_trapping_sleep_fn(void *flags)
-{
-	schedule();
-	return 0;
-}
-
 /*
  * ptrace a task: make the debugger its new parent and
  * move it to the ptrace list.
@@ -371,7 +365,7 @@
 out:
 	if (!retval) {
 		wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
-			    ptrace_trapping_sleep_fn, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 		proc_ptrace_connector(task, PTRACE_ATTACH);
 	}
 
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 0ffa20a..a104879 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -502,3 +502,21 @@
 	__wake_up_bit(atomic_t_waitqueue(p), p, WAIT_ATOMIC_T_BIT_NR);
 }
 EXPORT_SYMBOL(wake_up_atomic_t);
+
+__sched int bit_wait(void *word)
+{
+	if (signal_pending_state(current->state, current))
+		return 1;
+	schedule();
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait);
+
+__sched int bit_wait_io(void *word)
+{
+	if (signal_pending_state(current->state, current))
+		return 1;
+	io_schedule();
+	return 0;
+}
+EXPORT_SYMBOL(bit_wait_io);
diff --git a/mm/filemap.c b/mm/filemap.c
index dafb06f..d175917 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -241,18 +241,6 @@
 }
 EXPORT_SYMBOL(delete_from_page_cache);
 
-static int sleep_on_page(void *word)
-{
-	io_schedule();
-	return 0;
-}
-
-static int sleep_on_page_killable(void *word)
-{
-	sleep_on_page(word);
-	return fatal_signal_pending(current) ? -EINTR : 0;
-}
-
 static int filemap_check_errors(struct address_space *mapping)
 {
 	int ret = 0;
@@ -692,7 +680,7 @@
 	DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
 
 	if (test_bit(bit_nr, &page->flags))
-		__wait_on_bit(page_waitqueue(page), &wait, sleep_on_page,
+		__wait_on_bit(page_waitqueue(page), &wait, bit_wait_io,
 							TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(wait_on_page_bit);
@@ -705,7 +693,7 @@
 		return 0;
 
 	return __wait_on_bit(page_waitqueue(page), &wait,
-			     sleep_on_page_killable, TASK_KILLABLE);
+			     bit_wait_io, TASK_KILLABLE);
 }
 
 /**
@@ -806,7 +794,7 @@
 {
 	DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
 
-	__wait_on_bit_lock(page_waitqueue(page), &wait, sleep_on_page,
+	__wait_on_bit_lock(page_waitqueue(page), &wait, bit_wait_io,
 							TASK_UNINTERRUPTIBLE);
 }
 EXPORT_SYMBOL(__lock_page);
@@ -816,7 +804,7 @@
 	DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
 
 	return __wait_on_bit_lock(page_waitqueue(page), &wait,
-					sleep_on_page_killable, TASK_KILLABLE);
+					bit_wait_io, TASK_KILLABLE);
 }
 EXPORT_SYMBOL_GPL(__lock_page_killable);
 
diff --git a/mm/ksm.c b/mm/ksm.c
index 346ddc9..fb75902 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1978,18 +1978,12 @@
 #endif /* CONFIG_MIGRATION */
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-static int just_wait(void *word)
-{
-	schedule();
-	return 0;
-}
-
 static void wait_while_offlining(void)
 {
 	while (ksm_run & KSM_RUN_OFFLINE) {
 		mutex_unlock(&ksm_thread_mutex);
 		wait_on_bit(&ksm_run, ilog2(KSM_RUN_OFFLINE),
-				just_wait, TASK_UNINTERRUPTIBLE);
+			    TASK_UNINTERRUPTIBLE);
 		mutex_lock(&ksm_thread_mutex);
 	}
 }
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 0a43cce..e090bff 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2186,12 +2186,6 @@
 	hci_req_add(req, HCI_OP_INQUIRY, sizeof(cp), &cp);
 }
 
-static int wait_inquiry(void *word)
-{
-	schedule();
-	return signal_pending(current);
-}
-
 int hci_inquiry(void __user *arg)
 {
 	__u8 __user *ptr = arg;
@@ -2242,7 +2236,7 @@
 		/* Wait until Inquiry procedure finishes (HCI_INQUIRY flag is
 		 * cleared). If it is interrupted by a signal, return -EINTR.
 		 */
-		if (wait_on_bit(&hdev->flags, HCI_INQUIRY, wait_inquiry,
+		if (wait_on_bit(&hdev->flags, HCI_INQUIRY,
 				TASK_INTERRUPTIBLE))
 			return -EINTR;
 	}
diff --git a/security/keys/gc.c b/security/keys/gc.c
index d3222b6..9609a7f 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -92,15 +92,6 @@
 }
 
 /*
- * wait_on_bit() sleep function for uninterruptible waiting
- */
-static int key_gc_wait_bit(void *flags)
-{
-	schedule();
-	return 0;
-}
-
-/*
  * Reap keys of dead type.
  *
  * We use three flags to make sure we see three complete cycles of the garbage
@@ -123,7 +114,7 @@
 	schedule_work(&key_gc_work);
 
 	kdebug("sleep");
-	wait_on_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE, key_gc_wait_bit,
+	wait_on_bit(&key_gc_flags, KEY_GC_REAPING_KEYTYPE,
 		    TASK_UNINTERRUPTIBLE);
 
 	key_gc_dead_keytype = NULL;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 3814119..26a94f1 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -21,24 +21,6 @@
 
 #define key_negative_timeout	60	/* default timeout on a negative key's existence */
 
-/*
- * wait_on_bit() sleep function for uninterruptible waiting
- */
-static int key_wait_bit(void *flags)
-{
-	schedule();
-	return 0;
-}
-
-/*
- * wait_on_bit() sleep function for interruptible waiting
- */
-static int key_wait_bit_intr(void *flags)
-{
-	schedule();
-	return signal_pending(current) ? -ERESTARTSYS : 0;
-}
-
 /**
  * complete_request_key - Complete the construction of a key.
  * @cons: The key construction record.
@@ -592,10 +574,9 @@
 	int ret;
 
 	ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
-			  intr ? key_wait_bit_intr : key_wait_bit,
 			  intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
-	if (ret < 0)
-		return ret;
+	if (ret)
+		return -ERESTARTSYS;
 	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
 		smp_rmb();
 		return key->type_data.reject_error;