dm: split DMF_BLOCK_IO flag into two
Split the DMF_BLOCK_IO flag into two.
DMF_BLOCK_IO_FOR_SUSPEND is set when I/O must be blocked while suspending a
device. DMF_QUEUE_IO_TO_THREAD is set when I/O must be queued to a
worker thread for later processing.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 020a9e1..7cac722 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -89,12 +89,13 @@
/*
* Bits for the md->flags field.
*/
-#define DMF_BLOCK_IO 0
+#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_QUEUE_IO_TO_THREAD 6
/*
* Work processed by per-device workqueue.
@@ -439,7 +440,7 @@
{
down_write(&md->io_lock);
- if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
+ if (!test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) {
up_write(&md->io_lock);
return 1;
}
@@ -950,10 +951,10 @@
part_stat_unlock();
/*
- * If we're suspended we have to queue
- * this io for later.
+ * If we're suspended or the thread is processing barriers
+ * we have to queue this io for later.
*/
- while (test_bit(DMF_BLOCK_IO, &md->flags)) {
+ while (test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) {
up_read(&md->io_lock);
if (bio_rw(bio) != READA)
@@ -997,7 +998,7 @@
struct mapped_device *md = congested_data;
struct dm_table *map;
- if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
+ if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
map = dm_get_table(md);
if (map) {
r = dm_table_any_congested(map, bdi_bits);
@@ -1443,7 +1444,8 @@
spin_unlock_irq(&md->deferred_lock);
if (!c) {
- clear_bit(DMF_BLOCK_IO, &md->flags);
+ clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
break;
}
@@ -1574,10 +1576,12 @@
}
/*
- * First we set the BLOCK_IO flag so no more ios will be mapped.
+ * First we set the DMF_QUEUE_IO_TO_THREAD flag so no more ios
+ * will be mapped.
*/
down_write(&md->io_lock);
- set_bit(DMF_BLOCK_IO, &md->flags);
+ set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
+ set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
up_write(&md->io_lock);