Merge tag 'omap-for-v3.9/usb-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into next/soc

These changes contain the OMAP USB related platform data changes
that were dropped from linux next because of the merge conflicts
as requested by me and Olof. The reason was that at this point
we really should be able to do the arch/arm related changes
separately from driver changes to avoid dependencies between
branches.

These patches were initially part of the USB related MFD patches.
Based on our comments, Roger Quadros quickly reworked these
patches into a shared branch between ARM SoC tree and the MFD
tree, then separate patches for the OMAP platform data and
MFD driver.

Note that this branch will conflict with c1d1cd597fc7
("ARM: OMAP2+: omap_device: remove obsolete pm_lats and
early_device code"). Please see http://lkml.org/lkml/2013/2/11/16
for the merge resolution.

[arnd - resolved the merge conflict]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 32 insertions, 10 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 9a289d7..3993ebf 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -35,6 +35,8 @@ static DEFINE_IDR(ext_devt_idr);
 
 static struct device_type disk_type;
 
+static void disk_check_events(struct disk_events *ev,
+			      unsigned int *clearing_ptr);
 static void disk_alloc_events(struct gendisk *disk);
 static void disk_add_events(struct gendisk *disk);
 static void disk_del_events(struct gendisk *disk);
@@ -1549,6 +1551,7 @@ unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
 	const struct block_device_operations *bdops = disk->fops;
 	struct disk_events *ev = disk->ev;
 	unsigned int pending;
+	unsigned int clearing = mask;
 
 	if (!ev) {
 		/* for drivers still using the old ->media_changed method */
@@ -1558,34 +1561,53 @@ unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
 		return 0;
 	}
 
-	/* tell the workfn about the events being cleared */
+	disk_block_events(disk);
+
+	/*
+	 * store the union of mask and ev->clearing on the stack so that the
+	 * race with disk_flush_events does not cause ambiguity (ev->clearing
+	 * can still be modified even if events are blocked).
+	 */
 	spin_lock_irq(&ev->lock);
-	ev->clearing |= mask;
+	clearing |= ev->clearing;
+	ev->clearing = 0;
 	spin_unlock_irq(&ev->lock);
 
-	/* uncondtionally schedule event check and wait for it to finish */
-	disk_block_events(disk);
-	queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
-	flush_delayed_work(&ev->dwork);
-	__disk_unblock_events(disk, false);
+	disk_check_events(ev, &clearing);
+	/*
+	 * if ev->clearing is not 0, the disk_flush_events got called in the
+	 * middle of this function, so we want to run the workfn without delay.
+	 */
+	__disk_unblock_events(disk, ev->clearing ? true : false);
 
 	/* then, fetch and clear pending events */
 	spin_lock_irq(&ev->lock);
-	WARN_ON_ONCE(ev->clearing & mask);	/* cleared by workfn */
 	pending = ev->pending & mask;
 	ev->pending &= ~mask;
 	spin_unlock_irq(&ev->lock);
+	WARN_ON_ONCE(clearing & mask);
 
 	return pending;
 }
 
+/*
+ * Separate this part out so that a different pointer for clearing_ptr can be
+ * passed in for disk_clear_events.
+ */
 static void disk_events_workfn(struct work_struct *work)
 {
 	struct delayed_work *dwork = to_delayed_work(work);
 	struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
+
+	disk_check_events(ev, &ev->clearing);
+}
+
+static void disk_check_events(struct disk_events *ev,
+			      unsigned int *clearing_ptr)
+{
 	struct gendisk *disk = ev->disk;
 	char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
-	unsigned int clearing = ev->clearing;
+	unsigned int clearing = *clearing_ptr;
 	unsigned int events;
 	unsigned long intv;
 	int nr_events = 0, i;
@@ -1598,7 +1620,7 @@ static void disk_events_workfn(struct work_struct *work)
 
 	events &= ~ev->pending;
 	ev->pending |= events;
-	ev->clearing &= ~clearing;
+	*clearing_ptr &= ~clearing;
 
 	intv = disk_events_poll_jiffies(disk);
 	if (!ev->block && intv)