diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/genhd.c | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/block/genhd.c b/block/genhd.c index 9a289d7c84b..3993ebf4135 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) |